diff mbox

[v5] drm/i915/bxt: Broxton decoupled MMIO

Message ID 1479230360-22395-1-git-send-email-praveen.paneri@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Praveen Paneri Nov. 15, 2016, 5:19 p.m. UTC
Decoupled MMIO is an alternative way to access forcewake domain
registers, which requires less cycles for a single read/write and
avoids frequent software forcewake.
This certainly gives advantage over the forcewake as this new
mechanism “decouples” CPU cycles and allow them to complete even
when GT is in a CPD (frequency change) or C6 state.

This can co-exist with forcewake and we will continue to use forcewake
as appropriate. E.g. 64-bit register writes to avoid writing 2 dwords
separately and land into funny situations.

v2:
- Moved platform check out of the function and got rid of duplicate
 functions to find out decoupled power domain (Chris)
- Added a check for forcewake already held and skipped decoupled
 access (Chris)
- Skipped writing 64 bit registers through decoupled MMIO (Chris)

v3:
- Improved commit message with more info on decoupled mmio (Tvrtko)
- Changed decoupled operation to enum and used u32 instead of
 uint_32 data type for register offset (Tvrtko)
- Moved HAS_DECOUPLED_MMIO to device info (Tvrtko)
- Added lookup table for converting fw_engine to pd_engine (Tvrtko)
- Improved __gen9_decoupled_read and __gen9_decoupled_write
 routines (Tvrtko)

v4:
- Fixed alignment and variable names (Chris)
- Write GEN9_DECOUPLED_REG0_DW1 register in just one go (Zhe Wang)

v5:
- Changed HAS_DECOUPLED_MMIO() argument name to dev_priv (Tvrtko)
- Sanitize info->had_decoupled_mmio at init (Chris)

Signed-off-by: Zhe Wang <zhe1.wang@intel.com>
Signed-off-by: Praveen Paneri <praveen.paneri@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h     |  17 +++++-
 drivers/gpu/drm/i915/i915_pci.c     |   1 +
 drivers/gpu/drm/i915/i915_reg.h     |   7 +++
 drivers/gpu/drm/i915/intel_uncore.c | 115 ++++++++++++++++++++++++++++++++++++
 4 files changed, 139 insertions(+), 1 deletion(-)

Comments

Tvrtko Ursulin Nov. 16, 2016, 8:25 a.m. UTC | #1
On 15/11/2016 17:19, Praveen Paneri wrote:
> Decoupled MMIO is an alternative way to access forcewake domain
> registers, which requires less cycles for a single read/write and
> avoids frequent software forcewake.
> This certainly gives advantage over the forcewake as this new
> mechanism “decouples” CPU cycles and allow them to complete even
> when GT is in a CPD (frequency change) or C6 state.
>
> This can co-exist with forcewake and we will continue to use forcewake
> as appropriate. E.g. 64-bit register writes to avoid writing 2 dwords
> separately and land into funny situations.
>
> v2:
> - Moved platform check out of the function and got rid of duplicate
>  functions to find out decoupled power domain (Chris)
> - Added a check for forcewake already held and skipped decoupled
>  access (Chris)
> - Skipped writing 64 bit registers through decoupled MMIO (Chris)
>
> v3:
> - Improved commit message with more info on decoupled mmio (Tvrtko)
> - Changed decoupled operation to enum and used u32 instead of
>  uint_32 data type for register offset (Tvrtko)
> - Moved HAS_DECOUPLED_MMIO to device info (Tvrtko)
> - Added lookup table for converting fw_engine to pd_engine (Tvrtko)
> - Improved __gen9_decoupled_read and __gen9_decoupled_write
>  routines (Tvrtko)
>
> v4:
> - Fixed alignment and variable names (Chris)
> - Write GEN9_DECOUPLED_REG0_DW1 register in just one go (Zhe Wang)
>
> v5:
> - Changed HAS_DECOUPLED_MMIO() argument name to dev_priv (Tvrtko)
> - Sanitize info->had_decoupled_mmio at init (Chris)
>
> Signed-off-by: Zhe Wang <zhe1.wang@intel.com>
> Signed-off-by: Praveen Paneri <praveen.paneri@intel.com>
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Please put "(v4)" when you carry over the r-b and it wasn't explicitly 
said you are OK to just keep it.

> ---
>  drivers/gpu/drm/i915/i915_drv.h     |  17 +++++-
>  drivers/gpu/drm/i915/i915_pci.c     |   1 +
>  drivers/gpu/drm/i915/i915_reg.h     |   7 +++
>  drivers/gpu/drm/i915/intel_uncore.c | 115 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 139 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 4e7148a..c1eec04 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -549,6 +549,18 @@ enum forcewake_domains {
>  #define FW_REG_READ  (1)
>  #define FW_REG_WRITE (2)
>
> +enum decoupled_power_domain {
> +	GEN9_DECOUPLED_PD_BLITTER = 0,
> +	GEN9_DECOUPLED_PD_RENDER,
> +	GEN9_DECOUPLED_PD_MEDIA,
> +	GEN9_DECOUPLED_PD_ALL
> +};
> +
> +enum decoupled_ops {
> +	GEN9_DECOUPLED_OP_WRITE = 0,
> +	GEN9_DECOUPLED_OP_READ
> +};
> +
>  enum forcewake_domains
>  intel_uncore_forcewake_for_reg(struct drm_i915_private *dev_priv,
>  			       i915_reg_t reg, unsigned int op);
> @@ -683,7 +695,8 @@ struct intel_csr {
>  	func(cursor_needs_physical); \
>  	func(hws_needs_physical); \
>  	func(overlay_needs_physical); \
> -	func(supports_tv)
> +	func(supports_tv); \
> +	func(has_decoupled_mmio)
>
>  struct sseu_dev_info {
>  	u8 slice_mask;
> @@ -2652,6 +2665,8 @@ struct drm_i915_cmd_table {
>  #define GT_FREQUENCY_MULTIPLIER 50
>  #define GEN9_FREQ_SCALER 3
>
> +#define HAS_DECOUPLED_MMIO(dev_priv) (INTEL_INFO(dev_priv)->has_decoupled_mmio)
> +
>  #include "i915_trace.h"
>
>  static inline bool intel_scanout_needs_vtd_wa(struct drm_i915_private *dev_priv)
> diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
> index 70a99ce..fce8e19 100644
> --- a/drivers/gpu/drm/i915/i915_pci.c
> +++ b/drivers/gpu/drm/i915/i915_pci.c
> @@ -363,6 +363,7 @@
>  	.has_hw_contexts = 1,
>  	.has_logical_ring_contexts = 1,
>  	.has_guc = 1,
> +	.has_decoupled_mmio = 1,
>  	.ddb_size = 512,
>  	GEN_DEFAULT_PIPEOFFSETS,
>  	IVB_CURSOR_OFFSETS,
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 3361d7f..c70c07a 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -7342,6 +7342,13 @@ enum {
>  #define  SKL_FUSE_PG1_DIST_STATUS              (1<<26)
>  #define  SKL_FUSE_PG2_DIST_STATUS              (1<<25)
>
> +/* Decoupled MMIO register pair for kernel driver */
> +#define GEN9_DECOUPLED_REG0_DW0			_MMIO(0xF00)
> +#define GEN9_DECOUPLED_REG0_DW1			_MMIO(0xF04)
> +#define GEN9_DECOUPLED_DW1_GO			(1<<31)
> +#define GEN9_DECOUPLED_PD_SHIFT			28
> +#define GEN9_DECOUPLED_OP_SHIFT			24
> +
>  /* Per-pipe DDI Function Control */
>  #define _TRANS_DDI_FUNC_CTL_A		0x60400
>  #define _TRANS_DDI_FUNC_CTL_B		0x61400
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index e2b188d..e953303 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -402,6 +402,8 @@ static void intel_uncore_edram_detect(struct drm_i915_private *dev_priv)
>  static void __intel_uncore_early_sanitize(struct drm_i915_private *dev_priv,
>  					  bool restore_forcewake)
>  {
> +	struct intel_device_info *info = mkwrite_device_info(dev_priv);
> +
>  	/* clear out unclaimed reg detection bit */
>  	if (check_for_unclaimed_mmio(dev_priv))
>  		DRM_DEBUG("unclaimed mmio detected on uncore init, clearing\n");
> @@ -419,6 +421,10 @@ static void __intel_uncore_early_sanitize(struct drm_i915_private *dev_priv,
>  				   GT_FIFO_CTL_RC6_POLICY_STALL);
>  	}
>
> +	/* Enable Decoupled MMIO only on BXT C stepping onwards */
> +	if (!IS_BXT_REVID(dev_priv, BXT_REVID_C0, REVID_FOREVER))
> +		info->has_decoupled_mmio = false;

Why have you decided to put it in here? It doesn't make much difference 
except conceptually. This runs every time on resume while I thought 
intel_device_info_runtime_init would have been more appropriate.

Regards,

Tvrtko

> +
>  	intel_uncore_forcewake_reset(dev_priv, restore_forcewake);
>  }
>
> @@ -831,6 +837,66 @@ static bool is_gen8_shadowed(u32 offset)
>  	__unclaimed_reg_debug(dev_priv, reg, read, before);
>  }
>
> +static const enum decoupled_power_domain fw2dpd_domain[] = {
> +	GEN9_DECOUPLED_PD_RENDER,
> +	GEN9_DECOUPLED_PD_BLITTER,
> +	GEN9_DECOUPLED_PD_ALL,
> +	GEN9_DECOUPLED_PD_MEDIA,
> +	GEN9_DECOUPLED_PD_ALL,
> +	GEN9_DECOUPLED_PD_ALL,
> +	GEN9_DECOUPLED_PD_ALL
> +};
> +
> +/*
> + * Decoupled MMIO access for only 1 DWORD
> + */
> +static void __gen9_decoupled_mmio_access(struct drm_i915_private *dev_priv,
> +					 u32 reg,
> +					 enum forcewake_domains fw_domain,
> +					 enum decoupled_ops operation)
> +{
> +	enum decoupled_power_domain dp_domain;
> +	u32 ctrl_reg_data = 0;
> +
> +	dp_domain = fw2dpd_domain[fw_domain - 1];
> +
> +	ctrl_reg_data |= reg;
> +	ctrl_reg_data |= (operation << GEN9_DECOUPLED_OP_SHIFT);
> +	ctrl_reg_data |= (dp_domain << GEN9_DECOUPLED_PD_SHIFT);
> +	ctrl_reg_data |= GEN9_DECOUPLED_DW1_GO;
> +	__raw_i915_write32(dev_priv, GEN9_DECOUPLED_REG0_DW1, ctrl_reg_data);
> +
> +	if (wait_for_atomic((__raw_i915_read32(dev_priv,
> +			    GEN9_DECOUPLED_REG0_DW1) &
> +			    GEN9_DECOUPLED_DW1_GO) == 0,
> +			    FORCEWAKE_ACK_TIMEOUT_MS))
> +		DRM_ERROR("Decoupled MMIO wait timed out\n");
> +}
> +
> +static inline u32
> +__gen9_decoupled_mmio_read32(struct drm_i915_private *dev_priv,
> +			     u32 reg,
> +			     enum forcewake_domains fw_domain)
> +{
> +	__gen9_decoupled_mmio_access(dev_priv, reg, fw_domain,
> +				     GEN9_DECOUPLED_OP_READ);
> +
> +	return __raw_i915_read32(dev_priv, GEN9_DECOUPLED_REG0_DW0);
> +}
> +
> +static inline void
> +__gen9_decoupled_mmio_write(struct drm_i915_private *dev_priv,
> +			    u32 reg, u32 data,
> +			    enum forcewake_domains fw_domain)
> +{
> +
> +	__raw_i915_write32(dev_priv, GEN9_DECOUPLED_REG0_DW0, data);
> +
> +	__gen9_decoupled_mmio_access(dev_priv, reg, fw_domain,
> +				     GEN9_DECOUPLED_OP_WRITE);
> +}
> +
> +
>  #define GEN2_READ_HEADER(x) \
>  	u##x val = 0; \
>  	assert_rpm_wakelock_held(dev_priv);
> @@ -935,6 +1001,28 @@ static inline void __force_wake_auto(struct drm_i915_private *dev_priv,
>  	GEN6_READ_FOOTER; \
>  }
>
> +#define __gen9_decoupled_read(x) \
> +static u##x \
> +gen9_decoupled_read##x(struct drm_i915_private *dev_priv, \
> +		       i915_reg_t reg, bool trace) { \
> +	enum forcewake_domains fw_engine; \
> +	GEN6_READ_HEADER(x); \
> +	fw_engine = __fwtable_reg_read_fw_domains(offset); \
> +	if (fw_engine & ~dev_priv->uncore.fw_domains_active) { \
> +		unsigned i; \
> +		u32 *ptr_data = (u32 *) &val; \
> +		for (i = 0; i < x/32; i++, offset += sizeof(u32), ptr_data++) \
> +			*ptr_data = __gen9_decoupled_mmio_read32(dev_priv, \
> +								 offset, \
> +								 fw_engine); \
> +	} else { \
> +		val = __raw_i915_read##x(dev_priv, reg); \
> +	} \
> +	GEN6_READ_FOOTER; \
> +}
> +
> +__gen9_decoupled_read(32)
> +__gen9_decoupled_read(64)
>  __fwtable_read(8)
>  __fwtable_read(16)
>  __fwtable_read(32)
> @@ -1064,6 +1152,25 @@ static inline void __force_wake_auto(struct drm_i915_private *dev_priv,
>  	GEN6_WRITE_FOOTER; \
>  }
>
> +#define __gen9_decoupled_write(x) \
> +static void \
> +gen9_decoupled_write##x(struct drm_i915_private *dev_priv, \
> +			i915_reg_t reg, u##x val, \
> +		bool trace) { \
> +	enum forcewake_domains fw_engine; \
> +	GEN6_WRITE_HEADER; \
> +	fw_engine = __fwtable_reg_write_fw_domains(offset); \
> +	if (fw_engine & ~dev_priv->uncore.fw_domains_active) \
> +		__gen9_decoupled_mmio_write(dev_priv, \
> +					    offset, \
> +					    val, \
> +					    fw_engine); \
> +	else \
> +		__raw_i915_write##x(dev_priv, reg, val); \
> +	GEN6_WRITE_FOOTER; \
> +}
> +
> +__gen9_decoupled_write(32)
>  __fwtable_write(8)
>  __fwtable_write(16)
>  __fwtable_write(32)
> @@ -1287,6 +1394,14 @@ void intel_uncore_init(struct drm_i915_private *dev_priv)
>  		ASSIGN_FW_DOMAINS_TABLE(__gen9_fw_ranges);
>  		ASSIGN_WRITE_MMIO_VFUNCS(fwtable);
>  		ASSIGN_READ_MMIO_VFUNCS(fwtable);
> +		if (HAS_DECOUPLED_MMIO(dev_priv)) {
> +			dev_priv->uncore.funcs.mmio_readl =
> +						gen9_decoupled_read32;
> +			dev_priv->uncore.funcs.mmio_readq =
> +						gen9_decoupled_read64;
> +			dev_priv->uncore.funcs.mmio_writel =
> +						gen9_decoupled_write32;
> +		}
>  		break;
>  	case 8:
>  		if (IS_CHERRYVIEW(dev_priv)) {
>
Praveen Paneri Nov. 16, 2016, 9:03 a.m. UTC | #2
Hi Tvrtko,

On Wednesday 16 November 2016 01:55 PM, Tvrtko Ursulin wrote:
>
> On 15/11/2016 17:19, Praveen Paneri wrote:
>> Decoupled MMIO is an alternative way to access forcewake domain
>> registers, which requires less cycles for a single read/write and
>> avoids frequent software forcewake.
>> This certainly gives advantage over the forcewake as this new
>> mechanism “decouples” CPU cycles and allow them to complete even
>> when GT is in a CPD (frequency change) or C6 state.
>>
>> This can co-exist with forcewake and we will continue to use forcewake
>> as appropriate. E.g. 64-bit register writes to avoid writing 2 dwords
>> separately and land into funny situations.
>>
>> v2:
>> - Moved platform check out of the function and got rid of duplicate
>>  functions to find out decoupled power domain (Chris)
>> - Added a check for forcewake already held and skipped decoupled
>>  access (Chris)
>> - Skipped writing 64 bit registers through decoupled MMIO (Chris)
>>
>> v3:
>> - Improved commit message with more info on decoupled mmio (Tvrtko)
>> - Changed decoupled operation to enum and used u32 instead of
>>  uint_32 data type for register offset (Tvrtko)
>> - Moved HAS_DECOUPLED_MMIO to device info (Tvrtko)
>> - Added lookup table for converting fw_engine to pd_engine (Tvrtko)
>> - Improved __gen9_decoupled_read and __gen9_decoupled_write
>>  routines (Tvrtko)
>>
>> v4:
>> - Fixed alignment and variable names (Chris)
>> - Write GEN9_DECOUPLED_REG0_DW1 register in just one go (Zhe Wang)
>>
>> v5:
>> - Changed HAS_DECOUPLED_MMIO() argument name to dev_priv (Tvrtko)
>> - Sanitize info->had_decoupled_mmio at init (Chris)
>>
>> Signed-off-by: Zhe Wang <zhe1.wang@intel.com>
>> Signed-off-by: Praveen Paneri <praveen.paneri@intel.com>
>> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>
> Please put "(v4)" when you carry over the r-b and it wasn't explicitly
> said you are OK to just keep it.
Sure will take care going fwd.
>
>> ---
>>  drivers/gpu/drm/i915/i915_drv.h     |  17 +++++-
>>  drivers/gpu/drm/i915/i915_pci.c     |   1 +
>>  drivers/gpu/drm/i915/i915_reg.h     |   7 +++
>>  drivers/gpu/drm/i915/intel_uncore.c | 115
>> ++++++++++++++++++++++++++++++++++++
>>  4 files changed, 139 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h
>> b/drivers/gpu/drm/i915/i915_drv.h
>> index 4e7148a..c1eec04 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -549,6 +549,18 @@ enum forcewake_domains {
>>  #define FW_REG_READ  (1)
>>  #define FW_REG_WRITE (2)
>>
>> +enum decoupled_power_domain {
>> +    GEN9_DECOUPLED_PD_BLITTER = 0,
>> +    GEN9_DECOUPLED_PD_RENDER,
>> +    GEN9_DECOUPLED_PD_MEDIA,
>> +    GEN9_DECOUPLED_PD_ALL
>> +};
>> +
>> +enum decoupled_ops {
>> +    GEN9_DECOUPLED_OP_WRITE = 0,
>> +    GEN9_DECOUPLED_OP_READ
>> +};
>> +
>>  enum forcewake_domains
>>  intel_uncore_forcewake_for_reg(struct drm_i915_private *dev_priv,
>>                     i915_reg_t reg, unsigned int op);
>> @@ -683,7 +695,8 @@ struct intel_csr {
>>      func(cursor_needs_physical); \
>>      func(hws_needs_physical); \
>>      func(overlay_needs_physical); \
>> -    func(supports_tv)
>> +    func(supports_tv); \
>> +    func(has_decoupled_mmio)
>>
>>  struct sseu_dev_info {
>>      u8 slice_mask;
>> @@ -2652,6 +2665,8 @@ struct drm_i915_cmd_table {
>>  #define GT_FREQUENCY_MULTIPLIER 50
>>  #define GEN9_FREQ_SCALER 3
>>
>> +#define HAS_DECOUPLED_MMIO(dev_priv)
>> (INTEL_INFO(dev_priv)->has_decoupled_mmio)
>> +
>>  #include "i915_trace.h"
>>
>>  static inline bool intel_scanout_needs_vtd_wa(struct drm_i915_private
>> *dev_priv)
>> diff --git a/drivers/gpu/drm/i915/i915_pci.c
>> b/drivers/gpu/drm/i915/i915_pci.c
>> index 70a99ce..fce8e19 100644
>> --- a/drivers/gpu/drm/i915/i915_pci.c
>> +++ b/drivers/gpu/drm/i915/i915_pci.c
>> @@ -363,6 +363,7 @@
>>      .has_hw_contexts = 1,
>>      .has_logical_ring_contexts = 1,
>>      .has_guc = 1,
>> +    .has_decoupled_mmio = 1,
>>      .ddb_size = 512,
>>      GEN_DEFAULT_PIPEOFFSETS,
>>      IVB_CURSOR_OFFSETS,
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h
>> b/drivers/gpu/drm/i915/i915_reg.h
>> index 3361d7f..c70c07a 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -7342,6 +7342,13 @@ enum {
>>  #define  SKL_FUSE_PG1_DIST_STATUS              (1<<26)
>>  #define  SKL_FUSE_PG2_DIST_STATUS              (1<<25)
>>
>> +/* Decoupled MMIO register pair for kernel driver */
>> +#define GEN9_DECOUPLED_REG0_DW0            _MMIO(0xF00)
>> +#define GEN9_DECOUPLED_REG0_DW1            _MMIO(0xF04)
>> +#define GEN9_DECOUPLED_DW1_GO            (1<<31)
>> +#define GEN9_DECOUPLED_PD_SHIFT            28
>> +#define GEN9_DECOUPLED_OP_SHIFT            24
>> +
>>  /* Per-pipe DDI Function Control */
>>  #define _TRANS_DDI_FUNC_CTL_A        0x60400
>>  #define _TRANS_DDI_FUNC_CTL_B        0x61400
>> diff --git a/drivers/gpu/drm/i915/intel_uncore.c
>> b/drivers/gpu/drm/i915/intel_uncore.c
>> index e2b188d..e953303 100644
>> --- a/drivers/gpu/drm/i915/intel_uncore.c
>> +++ b/drivers/gpu/drm/i915/intel_uncore.c
>> @@ -402,6 +402,8 @@ static void intel_uncore_edram_detect(struct
>> drm_i915_private *dev_priv)
>>  static void __intel_uncore_early_sanitize(struct drm_i915_private
>> *dev_priv,
>>                        bool restore_forcewake)
>>  {
>> +    struct intel_device_info *info = mkwrite_device_info(dev_priv);
>> +
>>      /* clear out unclaimed reg detection bit */
>>      if (check_for_unclaimed_mmio(dev_priv))
>>          DRM_DEBUG("unclaimed mmio detected on uncore init, clearing\n");
>> @@ -419,6 +421,10 @@ static void __intel_uncore_early_sanitize(struct
>> drm_i915_private *dev_priv,
>>                     GT_FIFO_CTL_RC6_POLICY_STALL);
>>      }
>>
>> +    /* Enable Decoupled MMIO only on BXT C stepping onwards */
>> +    if (!IS_BXT_REVID(dev_priv, BXT_REVID_C0, REVID_FOREVER))
>> +        info->has_decoupled_mmio = false;
>
> Why have you decided to put it in here? It doesn't make much difference
> except conceptually. This runs every time on resume while I thought
> intel_device_info_runtime_init would have been more appropriate.
Sorry about picking the bad place for this but intel_uncore_init() which 
uses this info gets executed before intel_device_info_runtime_init() in 
driver_load sequence. If I am not wrong, we need to find an appropriate 
place for this.

Thanks,
Praveen
>
> Regards,
>
> Tvrtko
>
>> +
>>      intel_uncore_forcewake_reset(dev_priv, restore_forcewake);
>>  }
>>
>> @@ -831,6 +837,66 @@ static bool is_gen8_shadowed(u32 offset)
>>      __unclaimed_reg_debug(dev_priv, reg, read, before);
>>  }
>>
>> +static const enum decoupled_power_domain fw2dpd_domain[] = {
>> +    GEN9_DECOUPLED_PD_RENDER,
>> +    GEN9_DECOUPLED_PD_BLITTER,
>> +    GEN9_DECOUPLED_PD_ALL,
>> +    GEN9_DECOUPLED_PD_MEDIA,
>> +    GEN9_DECOUPLED_PD_ALL,
>> +    GEN9_DECOUPLED_PD_ALL,
>> +    GEN9_DECOUPLED_PD_ALL
>> +};
>> +
>> +/*
>> + * Decoupled MMIO access for only 1 DWORD
>> + */
>> +static void __gen9_decoupled_mmio_access(struct drm_i915_private
>> *dev_priv,
>> +                     u32 reg,
>> +                     enum forcewake_domains fw_domain,
>> +                     enum decoupled_ops operation)
>> +{
>> +    enum decoupled_power_domain dp_domain;
>> +    u32 ctrl_reg_data = 0;
>> +
>> +    dp_domain = fw2dpd_domain[fw_domain - 1];
>> +
>> +    ctrl_reg_data |= reg;
>> +    ctrl_reg_data |= (operation << GEN9_DECOUPLED_OP_SHIFT);
>> +    ctrl_reg_data |= (dp_domain << GEN9_DECOUPLED_PD_SHIFT);
>> +    ctrl_reg_data |= GEN9_DECOUPLED_DW1_GO;
>> +    __raw_i915_write32(dev_priv, GEN9_DECOUPLED_REG0_DW1,
>> ctrl_reg_data);
>> +
>> +    if (wait_for_atomic((__raw_i915_read32(dev_priv,
>> +                GEN9_DECOUPLED_REG0_DW1) &
>> +                GEN9_DECOUPLED_DW1_GO) == 0,
>> +                FORCEWAKE_ACK_TIMEOUT_MS))
>> +        DRM_ERROR("Decoupled MMIO wait timed out\n");
>> +}
>> +
>> +static inline u32
>> +__gen9_decoupled_mmio_read32(struct drm_i915_private *dev_priv,
>> +                 u32 reg,
>> +                 enum forcewake_domains fw_domain)
>> +{
>> +    __gen9_decoupled_mmio_access(dev_priv, reg, fw_domain,
>> +                     GEN9_DECOUPLED_OP_READ);
>> +
>> +    return __raw_i915_read32(dev_priv, GEN9_DECOUPLED_REG0_DW0);
>> +}
>> +
>> +static inline void
>> +__gen9_decoupled_mmio_write(struct drm_i915_private *dev_priv,
>> +                u32 reg, u32 data,
>> +                enum forcewake_domains fw_domain)
>> +{
>> +
>> +    __raw_i915_write32(dev_priv, GEN9_DECOUPLED_REG0_DW0, data);
>> +
>> +    __gen9_decoupled_mmio_access(dev_priv, reg, fw_domain,
>> +                     GEN9_DECOUPLED_OP_WRITE);
>> +}
>> +
>> +
>>  #define GEN2_READ_HEADER(x) \
>>      u##x val = 0; \
>>      assert_rpm_wakelock_held(dev_priv);
>> @@ -935,6 +1001,28 @@ static inline void __force_wake_auto(struct
>> drm_i915_private *dev_priv,
>>      GEN6_READ_FOOTER; \
>>  }
>>
>> +#define __gen9_decoupled_read(x) \
>> +static u##x \
>> +gen9_decoupled_read##x(struct drm_i915_private *dev_priv, \
>> +               i915_reg_t reg, bool trace) { \
>> +    enum forcewake_domains fw_engine; \
>> +    GEN6_READ_HEADER(x); \
>> +    fw_engine = __fwtable_reg_read_fw_domains(offset); \
>> +    if (fw_engine & ~dev_priv->uncore.fw_domains_active) { \
>> +        unsigned i; \
>> +        u32 *ptr_data = (u32 *) &val; \
>> +        for (i = 0; i < x/32; i++, offset += sizeof(u32), ptr_data++) \
>> +            *ptr_data = __gen9_decoupled_mmio_read32(dev_priv, \
>> +                                 offset, \
>> +                                 fw_engine); \
>> +    } else { \
>> +        val = __raw_i915_read##x(dev_priv, reg); \
>> +    } \
>> +    GEN6_READ_FOOTER; \
>> +}
>> +
>> +__gen9_decoupled_read(32)
>> +__gen9_decoupled_read(64)
>>  __fwtable_read(8)
>>  __fwtable_read(16)
>>  __fwtable_read(32)
>> @@ -1064,6 +1152,25 @@ static inline void __force_wake_auto(struct
>> drm_i915_private *dev_priv,
>>      GEN6_WRITE_FOOTER; \
>>  }
>>
>> +#define __gen9_decoupled_write(x) \
>> +static void \
>> +gen9_decoupled_write##x(struct drm_i915_private *dev_priv, \
>> +            i915_reg_t reg, u##x val, \
>> +        bool trace) { \
>> +    enum forcewake_domains fw_engine; \
>> +    GEN6_WRITE_HEADER; \
>> +    fw_engine = __fwtable_reg_write_fw_domains(offset); \
>> +    if (fw_engine & ~dev_priv->uncore.fw_domains_active) \
>> +        __gen9_decoupled_mmio_write(dev_priv, \
>> +                        offset, \
>> +                        val, \
>> +                        fw_engine); \
>> +    else \
>> +        __raw_i915_write##x(dev_priv, reg, val); \
>> +    GEN6_WRITE_FOOTER; \
>> +}
>> +
>> +__gen9_decoupled_write(32)
>>  __fwtable_write(8)
>>  __fwtable_write(16)
>>  __fwtable_write(32)
>> @@ -1287,6 +1394,14 @@ void intel_uncore_init(struct drm_i915_private
>> *dev_priv)
>>          ASSIGN_FW_DOMAINS_TABLE(__gen9_fw_ranges);
>>          ASSIGN_WRITE_MMIO_VFUNCS(fwtable);
>>          ASSIGN_READ_MMIO_VFUNCS(fwtable);
>> +        if (HAS_DECOUPLED_MMIO(dev_priv)) {
>> +            dev_priv->uncore.funcs.mmio_readl =
>> +                        gen9_decoupled_read32;
>> +            dev_priv->uncore.funcs.mmio_readq =
>> +                        gen9_decoupled_read64;
>> +            dev_priv->uncore.funcs.mmio_writel =
>> +                        gen9_decoupled_write32;
>> +        }
>>          break;
>>      case 8:
>>          if (IS_CHERRYVIEW(dev_priv)) {
>>
Tvrtko Ursulin Nov. 16, 2016, 9:08 a.m. UTC | #3
On 16/11/2016 09:03, Praveen Paneri wrote:
> Hi Tvrtko,
>
> On Wednesday 16 November 2016 01:55 PM, Tvrtko Ursulin wrote:
>>
>> On 15/11/2016 17:19, Praveen Paneri wrote:
>>> Decoupled MMIO is an alternative way to access forcewake domain
>>> registers, which requires less cycles for a single read/write and
>>> avoids frequent software forcewake.
>>> This certainly gives advantage over the forcewake as this new
>>> mechanism “decouples” CPU cycles and allow them to complete even
>>> when GT is in a CPD (frequency change) or C6 state.
>>>
>>> This can co-exist with forcewake and we will continue to use forcewake
>>> as appropriate. E.g. 64-bit register writes to avoid writing 2 dwords
>>> separately and land into funny situations.
>>>
>>> v2:
>>> - Moved platform check out of the function and got rid of duplicate
>>>  functions to find out decoupled power domain (Chris)
>>> - Added a check for forcewake already held and skipped decoupled
>>>  access (Chris)
>>> - Skipped writing 64 bit registers through decoupled MMIO (Chris)
>>>
>>> v3:
>>> - Improved commit message with more info on decoupled mmio (Tvrtko)
>>> - Changed decoupled operation to enum and used u32 instead of
>>>  uint_32 data type for register offset (Tvrtko)
>>> - Moved HAS_DECOUPLED_MMIO to device info (Tvrtko)
>>> - Added lookup table for converting fw_engine to pd_engine (Tvrtko)
>>> - Improved __gen9_decoupled_read and __gen9_decoupled_write
>>>  routines (Tvrtko)
>>>
>>> v4:
>>> - Fixed alignment and variable names (Chris)
>>> - Write GEN9_DECOUPLED_REG0_DW1 register in just one go (Zhe Wang)
>>>
>>> v5:
>>> - Changed HAS_DECOUPLED_MMIO() argument name to dev_priv (Tvrtko)
>>> - Sanitize info->had_decoupled_mmio at init (Chris)
>>>
>>> Signed-off-by: Zhe Wang <zhe1.wang@intel.com>
>>> Signed-off-by: Praveen Paneri <praveen.paneri@intel.com>
>>> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>>
>> Please put "(v4)" when you carry over the r-b and it wasn't explicitly
>> said you are OK to just keep it.
> Sure will take care going fwd.
>>
>>> ---
>>>  drivers/gpu/drm/i915/i915_drv.h     |  17 +++++-
>>>  drivers/gpu/drm/i915/i915_pci.c     |   1 +
>>>  drivers/gpu/drm/i915/i915_reg.h     |   7 +++
>>>  drivers/gpu/drm/i915/intel_uncore.c | 115
>>> ++++++++++++++++++++++++++++++++++++
>>>  4 files changed, 139 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_drv.h
>>> b/drivers/gpu/drm/i915/i915_drv.h
>>> index 4e7148a..c1eec04 100644
>>> --- a/drivers/gpu/drm/i915/i915_drv.h
>>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>>> @@ -549,6 +549,18 @@ enum forcewake_domains {
>>>  #define FW_REG_READ  (1)
>>>  #define FW_REG_WRITE (2)
>>>
>>> +enum decoupled_power_domain {
>>> +    GEN9_DECOUPLED_PD_BLITTER = 0,
>>> +    GEN9_DECOUPLED_PD_RENDER,
>>> +    GEN9_DECOUPLED_PD_MEDIA,
>>> +    GEN9_DECOUPLED_PD_ALL
>>> +};
>>> +
>>> +enum decoupled_ops {
>>> +    GEN9_DECOUPLED_OP_WRITE = 0,
>>> +    GEN9_DECOUPLED_OP_READ
>>> +};
>>> +
>>>  enum forcewake_domains
>>>  intel_uncore_forcewake_for_reg(struct drm_i915_private *dev_priv,
>>>                     i915_reg_t reg, unsigned int op);
>>> @@ -683,7 +695,8 @@ struct intel_csr {
>>>      func(cursor_needs_physical); \
>>>      func(hws_needs_physical); \
>>>      func(overlay_needs_physical); \
>>> -    func(supports_tv)
>>> +    func(supports_tv); \
>>> +    func(has_decoupled_mmio)
>>>
>>>  struct sseu_dev_info {
>>>      u8 slice_mask;
>>> @@ -2652,6 +2665,8 @@ struct drm_i915_cmd_table {
>>>  #define GT_FREQUENCY_MULTIPLIER 50
>>>  #define GEN9_FREQ_SCALER 3
>>>
>>> +#define HAS_DECOUPLED_MMIO(dev_priv)
>>> (INTEL_INFO(dev_priv)->has_decoupled_mmio)
>>> +
>>>  #include "i915_trace.h"
>>>
>>>  static inline bool intel_scanout_needs_vtd_wa(struct drm_i915_private
>>> *dev_priv)
>>> diff --git a/drivers/gpu/drm/i915/i915_pci.c
>>> b/drivers/gpu/drm/i915/i915_pci.c
>>> index 70a99ce..fce8e19 100644
>>> --- a/drivers/gpu/drm/i915/i915_pci.c
>>> +++ b/drivers/gpu/drm/i915/i915_pci.c
>>> @@ -363,6 +363,7 @@
>>>      .has_hw_contexts = 1,
>>>      .has_logical_ring_contexts = 1,
>>>      .has_guc = 1,
>>> +    .has_decoupled_mmio = 1,
>>>      .ddb_size = 512,
>>>      GEN_DEFAULT_PIPEOFFSETS,
>>>      IVB_CURSOR_OFFSETS,
>>> diff --git a/drivers/gpu/drm/i915/i915_reg.h
>>> b/drivers/gpu/drm/i915/i915_reg.h
>>> index 3361d7f..c70c07a 100644
>>> --- a/drivers/gpu/drm/i915/i915_reg.h
>>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>>> @@ -7342,6 +7342,13 @@ enum {
>>>  #define  SKL_FUSE_PG1_DIST_STATUS              (1<<26)
>>>  #define  SKL_FUSE_PG2_DIST_STATUS              (1<<25)
>>>
>>> +/* Decoupled MMIO register pair for kernel driver */
>>> +#define GEN9_DECOUPLED_REG0_DW0            _MMIO(0xF00)
>>> +#define GEN9_DECOUPLED_REG0_DW1            _MMIO(0xF04)
>>> +#define GEN9_DECOUPLED_DW1_GO            (1<<31)
>>> +#define GEN9_DECOUPLED_PD_SHIFT            28
>>> +#define GEN9_DECOUPLED_OP_SHIFT            24
>>> +
>>>  /* Per-pipe DDI Function Control */
>>>  #define _TRANS_DDI_FUNC_CTL_A        0x60400
>>>  #define _TRANS_DDI_FUNC_CTL_B        0x61400
>>> diff --git a/drivers/gpu/drm/i915/intel_uncore.c
>>> b/drivers/gpu/drm/i915/intel_uncore.c
>>> index e2b188d..e953303 100644
>>> --- a/drivers/gpu/drm/i915/intel_uncore.c
>>> +++ b/drivers/gpu/drm/i915/intel_uncore.c
>>> @@ -402,6 +402,8 @@ static void intel_uncore_edram_detect(struct
>>> drm_i915_private *dev_priv)
>>>  static void __intel_uncore_early_sanitize(struct drm_i915_private
>>> *dev_priv,
>>>                        bool restore_forcewake)
>>>  {
>>> +    struct intel_device_info *info = mkwrite_device_info(dev_priv);
>>> +
>>>      /* clear out unclaimed reg detection bit */
>>>      if (check_for_unclaimed_mmio(dev_priv))
>>>          DRM_DEBUG("unclaimed mmio detected on uncore init,
>>> clearing\n");
>>> @@ -419,6 +421,10 @@ static void __intel_uncore_early_sanitize(struct
>>> drm_i915_private *dev_priv,
>>>                     GT_FIFO_CTL_RC6_POLICY_STALL);
>>>      }
>>>
>>> +    /* Enable Decoupled MMIO only on BXT C stepping onwards */
>>> +    if (!IS_BXT_REVID(dev_priv, BXT_REVID_C0, REVID_FOREVER))
>>> +        info->has_decoupled_mmio = false;
>>
>> Why have you decided to put it in here? It doesn't make much difference
>> except conceptually. This runs every time on resume while I thought
>> intel_device_info_runtime_init would have been more appropriate.
> Sorry about picking the bad place for this but intel_uncore_init() which
> uses this info gets executed before intel_device_info_runtime_init() in
> driver_load sequence. If I am not wrong, we need to find an appropriate
> place for this.

You are correct, very illogical. Someone else can fix that so:

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko
Chris Wilson Nov. 16, 2016, 9:18 a.m. UTC | #4
On Wed, Nov 16, 2016 at 09:08:30AM +0000, Tvrtko Ursulin wrote:
> 
> On 16/11/2016 09:03, Praveen Paneri wrote:
> >Hi Tvrtko,
> >
> >On Wednesday 16 November 2016 01:55 PM, Tvrtko Ursulin wrote:
> >>
> >>On 15/11/2016 17:19, Praveen Paneri wrote:
> >>>Decoupled MMIO is an alternative way to access forcewake domain
> >>>registers, which requires less cycles for a single read/write and
> >>>avoids frequent software forcewake.
> >>>This certainly gives advantage over the forcewake as this new
> >>>mechanism “decouples” CPU cycles and allow them to complete even
> >>>when GT is in a CPD (frequency change) or C6 state.
> >>>
> >>>This can co-exist with forcewake and we will continue to use forcewake
> >>>as appropriate. E.g. 64-bit register writes to avoid writing 2 dwords
> >>>separately and land into funny situations.
> >>>
> >>>v2:
> >>>- Moved platform check out of the function and got rid of duplicate
> >>> functions to find out decoupled power domain (Chris)
> >>>- Added a check for forcewake already held and skipped decoupled
> >>> access (Chris)
> >>>- Skipped writing 64 bit registers through decoupled MMIO (Chris)
> >>>
> >>>v3:
> >>>- Improved commit message with more info on decoupled mmio (Tvrtko)
> >>>- Changed decoupled operation to enum and used u32 instead of
> >>> uint_32 data type for register offset (Tvrtko)
> >>>- Moved HAS_DECOUPLED_MMIO to device info (Tvrtko)
> >>>- Added lookup table for converting fw_engine to pd_engine (Tvrtko)
> >>>- Improved __gen9_decoupled_read and __gen9_decoupled_write
> >>> routines (Tvrtko)
> >>>
> >>>v4:
> >>>- Fixed alignment and variable names (Chris)
> >>>- Write GEN9_DECOUPLED_REG0_DW1 register in just one go (Zhe Wang)
> >>>
> >>>v5:
> >>>- Changed HAS_DECOUPLED_MMIO() argument name to dev_priv (Tvrtko)
> >>>- Sanitize info->had_decoupled_mmio at init (Chris)
> >>>
> >>>Signed-off-by: Zhe Wang <zhe1.wang@intel.com>
> >>>Signed-off-by: Praveen Paneri <praveen.paneri@intel.com>
> >>>Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> >>
> >>Please put "(v4)" when you carry over the r-b and it wasn't explicitly
> >>said you are OK to just keep it.
> >Sure will take care going fwd.
> >>
> >>>---
> >>> drivers/gpu/drm/i915/i915_drv.h     |  17 +++++-
> >>> drivers/gpu/drm/i915/i915_pci.c     |   1 +
> >>> drivers/gpu/drm/i915/i915_reg.h     |   7 +++
> >>> drivers/gpu/drm/i915/intel_uncore.c | 115
> >>>++++++++++++++++++++++++++++++++++++
> >>> 4 files changed, 139 insertions(+), 1 deletion(-)
> >>>
> >>>diff --git a/drivers/gpu/drm/i915/i915_drv.h
> >>>b/drivers/gpu/drm/i915/i915_drv.h
> >>>index 4e7148a..c1eec04 100644
> >>>--- a/drivers/gpu/drm/i915/i915_drv.h
> >>>+++ b/drivers/gpu/drm/i915/i915_drv.h
> >>>@@ -549,6 +549,18 @@ enum forcewake_domains {
> >>> #define FW_REG_READ  (1)
> >>> #define FW_REG_WRITE (2)
> >>>
> >>>+enum decoupled_power_domain {
> >>>+    GEN9_DECOUPLED_PD_BLITTER = 0,
> >>>+    GEN9_DECOUPLED_PD_RENDER,
> >>>+    GEN9_DECOUPLED_PD_MEDIA,
> >>>+    GEN9_DECOUPLED_PD_ALL
> >>>+};
> >>>+
> >>>+enum decoupled_ops {
> >>>+    GEN9_DECOUPLED_OP_WRITE = 0,
> >>>+    GEN9_DECOUPLED_OP_READ
> >>>+};
> >>>+
> >>> enum forcewake_domains
> >>> intel_uncore_forcewake_for_reg(struct drm_i915_private *dev_priv,
> >>>                    i915_reg_t reg, unsigned int op);
> >>>@@ -683,7 +695,8 @@ struct intel_csr {
> >>>     func(cursor_needs_physical); \
> >>>     func(hws_needs_physical); \
> >>>     func(overlay_needs_physical); \
> >>>-    func(supports_tv)
> >>>+    func(supports_tv); \
> >>>+    func(has_decoupled_mmio)
> >>>
> >>> struct sseu_dev_info {
> >>>     u8 slice_mask;
> >>>@@ -2652,6 +2665,8 @@ struct drm_i915_cmd_table {
> >>> #define GT_FREQUENCY_MULTIPLIER 50
> >>> #define GEN9_FREQ_SCALER 3
> >>>
> >>>+#define HAS_DECOUPLED_MMIO(dev_priv)
> >>>(INTEL_INFO(dev_priv)->has_decoupled_mmio)
> >>>+
> >>> #include "i915_trace.h"
> >>>
> >>> static inline bool intel_scanout_needs_vtd_wa(struct drm_i915_private
> >>>*dev_priv)
> >>>diff --git a/drivers/gpu/drm/i915/i915_pci.c
> >>>b/drivers/gpu/drm/i915/i915_pci.c
> >>>index 70a99ce..fce8e19 100644
> >>>--- a/drivers/gpu/drm/i915/i915_pci.c
> >>>+++ b/drivers/gpu/drm/i915/i915_pci.c
> >>>@@ -363,6 +363,7 @@
> >>>     .has_hw_contexts = 1,
> >>>     .has_logical_ring_contexts = 1,
> >>>     .has_guc = 1,
> >>>+    .has_decoupled_mmio = 1,
> >>>     .ddb_size = 512,
> >>>     GEN_DEFAULT_PIPEOFFSETS,
> >>>     IVB_CURSOR_OFFSETS,
> >>>diff --git a/drivers/gpu/drm/i915/i915_reg.h
> >>>b/drivers/gpu/drm/i915/i915_reg.h
> >>>index 3361d7f..c70c07a 100644
> >>>--- a/drivers/gpu/drm/i915/i915_reg.h
> >>>+++ b/drivers/gpu/drm/i915/i915_reg.h
> >>>@@ -7342,6 +7342,13 @@ enum {
> >>> #define  SKL_FUSE_PG1_DIST_STATUS              (1<<26)
> >>> #define  SKL_FUSE_PG2_DIST_STATUS              (1<<25)
> >>>
> >>>+/* Decoupled MMIO register pair for kernel driver */
> >>>+#define GEN9_DECOUPLED_REG0_DW0            _MMIO(0xF00)
> >>>+#define GEN9_DECOUPLED_REG0_DW1            _MMIO(0xF04)
> >>>+#define GEN9_DECOUPLED_DW1_GO            (1<<31)
> >>>+#define GEN9_DECOUPLED_PD_SHIFT            28
> >>>+#define GEN9_DECOUPLED_OP_SHIFT            24
> >>>+
> >>> /* Per-pipe DDI Function Control */
> >>> #define _TRANS_DDI_FUNC_CTL_A        0x60400
> >>> #define _TRANS_DDI_FUNC_CTL_B        0x61400
> >>>diff --git a/drivers/gpu/drm/i915/intel_uncore.c
> >>>b/drivers/gpu/drm/i915/intel_uncore.c
> >>>index e2b188d..e953303 100644
> >>>--- a/drivers/gpu/drm/i915/intel_uncore.c
> >>>+++ b/drivers/gpu/drm/i915/intel_uncore.c
> >>>@@ -402,6 +402,8 @@ static void intel_uncore_edram_detect(struct
> >>>drm_i915_private *dev_priv)
> >>> static void __intel_uncore_early_sanitize(struct drm_i915_private
> >>>*dev_priv,
> >>>                       bool restore_forcewake)
> >>> {
> >>>+    struct intel_device_info *info = mkwrite_device_info(dev_priv);
> >>>+
> >>>     /* clear out unclaimed reg detection bit */
> >>>     if (check_for_unclaimed_mmio(dev_priv))
> >>>         DRM_DEBUG("unclaimed mmio detected on uncore init,
> >>>clearing\n");
> >>>@@ -419,6 +421,10 @@ static void __intel_uncore_early_sanitize(struct
> >>>drm_i915_private *dev_priv,
> >>>                    GT_FIFO_CTL_RC6_POLICY_STALL);
> >>>     }
> >>>
> >>>+    /* Enable Decoupled MMIO only on BXT C stepping onwards */
> >>>+    if (!IS_BXT_REVID(dev_priv, BXT_REVID_C0, REVID_FOREVER))
> >>>+        info->has_decoupled_mmio = false;
> >>
> >>Why have you decided to put it in here? It doesn't make much difference
> >>except conceptually. This runs every time on resume while I thought
> >>intel_device_info_runtime_init would have been more appropriate.
> >Sorry about picking the bad place for this but intel_uncore_init() which
> >uses this info gets executed before intel_device_info_runtime_init() in
> >driver_load sequence. If I am not wrong, we need to find an appropriate
> >place for this.
> 
> You are correct, very illogical. Someone else can fix that so:

Ugh. It has some post-display fixups as well as early sanitization. As
soon as someone is finished with purging the mix of dev/dev_priv they
may feel inclined to split that up appropriately...
-Chris
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 4e7148a..c1eec04 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -549,6 +549,18 @@  enum forcewake_domains {
 #define FW_REG_READ  (1)
 #define FW_REG_WRITE (2)
 
+enum decoupled_power_domain {
+	GEN9_DECOUPLED_PD_BLITTER = 0,
+	GEN9_DECOUPLED_PD_RENDER,
+	GEN9_DECOUPLED_PD_MEDIA,
+	GEN9_DECOUPLED_PD_ALL
+};
+
+enum decoupled_ops {
+	GEN9_DECOUPLED_OP_WRITE = 0,
+	GEN9_DECOUPLED_OP_READ
+};
+
 enum forcewake_domains
 intel_uncore_forcewake_for_reg(struct drm_i915_private *dev_priv,
 			       i915_reg_t reg, unsigned int op);
@@ -683,7 +695,8 @@  struct intel_csr {
 	func(cursor_needs_physical); \
 	func(hws_needs_physical); \
 	func(overlay_needs_physical); \
-	func(supports_tv)
+	func(supports_tv); \
+	func(has_decoupled_mmio)
 
 struct sseu_dev_info {
 	u8 slice_mask;
@@ -2652,6 +2665,8 @@  struct drm_i915_cmd_table {
 #define GT_FREQUENCY_MULTIPLIER 50
 #define GEN9_FREQ_SCALER 3
 
+#define HAS_DECOUPLED_MMIO(dev_priv) (INTEL_INFO(dev_priv)->has_decoupled_mmio)
+
 #include "i915_trace.h"
 
 static inline bool intel_scanout_needs_vtd_wa(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
index 70a99ce..fce8e19 100644
--- a/drivers/gpu/drm/i915/i915_pci.c
+++ b/drivers/gpu/drm/i915/i915_pci.c
@@ -363,6 +363,7 @@ 
 	.has_hw_contexts = 1,
 	.has_logical_ring_contexts = 1,
 	.has_guc = 1,
+	.has_decoupled_mmio = 1,
 	.ddb_size = 512,
 	GEN_DEFAULT_PIPEOFFSETS,
 	IVB_CURSOR_OFFSETS,
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 3361d7f..c70c07a 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7342,6 +7342,13 @@  enum {
 #define  SKL_FUSE_PG1_DIST_STATUS              (1<<26)
 #define  SKL_FUSE_PG2_DIST_STATUS              (1<<25)
 
+/* Decoupled MMIO register pair for kernel driver */
+#define GEN9_DECOUPLED_REG0_DW0			_MMIO(0xF00)
+#define GEN9_DECOUPLED_REG0_DW1			_MMIO(0xF04)
+#define GEN9_DECOUPLED_DW1_GO			(1<<31)
+#define GEN9_DECOUPLED_PD_SHIFT			28
+#define GEN9_DECOUPLED_OP_SHIFT			24
+
 /* Per-pipe DDI Function Control */
 #define _TRANS_DDI_FUNC_CTL_A		0x60400
 #define _TRANS_DDI_FUNC_CTL_B		0x61400
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index e2b188d..e953303 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -402,6 +402,8 @@  static void intel_uncore_edram_detect(struct drm_i915_private *dev_priv)
 static void __intel_uncore_early_sanitize(struct drm_i915_private *dev_priv,
 					  bool restore_forcewake)
 {
+	struct intel_device_info *info = mkwrite_device_info(dev_priv);
+
 	/* clear out unclaimed reg detection bit */
 	if (check_for_unclaimed_mmio(dev_priv))
 		DRM_DEBUG("unclaimed mmio detected on uncore init, clearing\n");
@@ -419,6 +421,10 @@  static void __intel_uncore_early_sanitize(struct drm_i915_private *dev_priv,
 				   GT_FIFO_CTL_RC6_POLICY_STALL);
 	}
 
+	/* Enable Decoupled MMIO only on BXT C stepping onwards */
+	if (!IS_BXT_REVID(dev_priv, BXT_REVID_C0, REVID_FOREVER))
+		info->has_decoupled_mmio = false;
+
 	intel_uncore_forcewake_reset(dev_priv, restore_forcewake);
 }
 
@@ -831,6 +837,66 @@  static bool is_gen8_shadowed(u32 offset)
 	__unclaimed_reg_debug(dev_priv, reg, read, before);
 }
 
+static const enum decoupled_power_domain fw2dpd_domain[] = {
+	GEN9_DECOUPLED_PD_RENDER,
+	GEN9_DECOUPLED_PD_BLITTER,
+	GEN9_DECOUPLED_PD_ALL,
+	GEN9_DECOUPLED_PD_MEDIA,
+	GEN9_DECOUPLED_PD_ALL,
+	GEN9_DECOUPLED_PD_ALL,
+	GEN9_DECOUPLED_PD_ALL
+};
+
+/*
+ * Decoupled MMIO access for only 1 DWORD
+ */
+static void __gen9_decoupled_mmio_access(struct drm_i915_private *dev_priv,
+					 u32 reg,
+					 enum forcewake_domains fw_domain,
+					 enum decoupled_ops operation)
+{
+	enum decoupled_power_domain dp_domain;
+	u32 ctrl_reg_data = 0;
+
+	dp_domain = fw2dpd_domain[fw_domain - 1];
+
+	ctrl_reg_data |= reg;
+	ctrl_reg_data |= (operation << GEN9_DECOUPLED_OP_SHIFT);
+	ctrl_reg_data |= (dp_domain << GEN9_DECOUPLED_PD_SHIFT);
+	ctrl_reg_data |= GEN9_DECOUPLED_DW1_GO;
+	__raw_i915_write32(dev_priv, GEN9_DECOUPLED_REG0_DW1, ctrl_reg_data);
+
+	if (wait_for_atomic((__raw_i915_read32(dev_priv,
+			    GEN9_DECOUPLED_REG0_DW1) &
+			    GEN9_DECOUPLED_DW1_GO) == 0,
+			    FORCEWAKE_ACK_TIMEOUT_MS))
+		DRM_ERROR("Decoupled MMIO wait timed out\n");
+}
+
+static inline u32
+__gen9_decoupled_mmio_read32(struct drm_i915_private *dev_priv,
+			     u32 reg,
+			     enum forcewake_domains fw_domain)
+{
+	__gen9_decoupled_mmio_access(dev_priv, reg, fw_domain,
+				     GEN9_DECOUPLED_OP_READ);
+
+	return __raw_i915_read32(dev_priv, GEN9_DECOUPLED_REG0_DW0);
+}
+
+static inline void
+__gen9_decoupled_mmio_write(struct drm_i915_private *dev_priv,
+			    u32 reg, u32 data,
+			    enum forcewake_domains fw_domain)
+{
+
+	__raw_i915_write32(dev_priv, GEN9_DECOUPLED_REG0_DW0, data);
+
+	__gen9_decoupled_mmio_access(dev_priv, reg, fw_domain,
+				     GEN9_DECOUPLED_OP_WRITE);
+}
+
+
 #define GEN2_READ_HEADER(x) \
 	u##x val = 0; \
 	assert_rpm_wakelock_held(dev_priv);
@@ -935,6 +1001,28 @@  static inline void __force_wake_auto(struct drm_i915_private *dev_priv,
 	GEN6_READ_FOOTER; \
 }
 
+#define __gen9_decoupled_read(x) \
+static u##x \
+gen9_decoupled_read##x(struct drm_i915_private *dev_priv, \
+		       i915_reg_t reg, bool trace) { \
+	enum forcewake_domains fw_engine; \
+	GEN6_READ_HEADER(x); \
+	fw_engine = __fwtable_reg_read_fw_domains(offset); \
+	if (fw_engine & ~dev_priv->uncore.fw_domains_active) { \
+		unsigned i; \
+		u32 *ptr_data = (u32 *) &val; \
+		for (i = 0; i < x/32; i++, offset += sizeof(u32), ptr_data++) \
+			*ptr_data = __gen9_decoupled_mmio_read32(dev_priv, \
+								 offset, \
+								 fw_engine); \
+	} else { \
+		val = __raw_i915_read##x(dev_priv, reg); \
+	} \
+	GEN6_READ_FOOTER; \
+}
+
+__gen9_decoupled_read(32)
+__gen9_decoupled_read(64)
 __fwtable_read(8)
 __fwtable_read(16)
 __fwtable_read(32)
@@ -1064,6 +1152,25 @@  static inline void __force_wake_auto(struct drm_i915_private *dev_priv,
 	GEN6_WRITE_FOOTER; \
 }
 
+#define __gen9_decoupled_write(x) \
+static void \
+gen9_decoupled_write##x(struct drm_i915_private *dev_priv, \
+			i915_reg_t reg, u##x val, \
+		bool trace) { \
+	enum forcewake_domains fw_engine; \
+	GEN6_WRITE_HEADER; \
+	fw_engine = __fwtable_reg_write_fw_domains(offset); \
+	if (fw_engine & ~dev_priv->uncore.fw_domains_active) \
+		__gen9_decoupled_mmio_write(dev_priv, \
+					    offset, \
+					    val, \
+					    fw_engine); \
+	else \
+		__raw_i915_write##x(dev_priv, reg, val); \
+	GEN6_WRITE_FOOTER; \
+}
+
+__gen9_decoupled_write(32)
 __fwtable_write(8)
 __fwtable_write(16)
 __fwtable_write(32)
@@ -1287,6 +1394,14 @@  void intel_uncore_init(struct drm_i915_private *dev_priv)
 		ASSIGN_FW_DOMAINS_TABLE(__gen9_fw_ranges);
 		ASSIGN_WRITE_MMIO_VFUNCS(fwtable);
 		ASSIGN_READ_MMIO_VFUNCS(fwtable);
+		if (HAS_DECOUPLED_MMIO(dev_priv)) {
+			dev_priv->uncore.funcs.mmio_readl =
+						gen9_decoupled_read32;
+			dev_priv->uncore.funcs.mmio_readq =
+						gen9_decoupled_read64;
+			dev_priv->uncore.funcs.mmio_writel =
+						gen9_decoupled_write32;
+		}
 		break;
 	case 8:
 		if (IS_CHERRYVIEW(dev_priv)) {