diff mbox series

[2/3] drm/msm/dsi/phy: Protect PHY_CMN_CLK_CFG1 against clock driver

Message ID 20250131-drm-msm-phy-pll-cfg-reg-v1-2-3b99efeb2e8d@linaro.org (mailing list archive)
State New
Headers show
Series drm/msm/dsi/phy: Improvements around concurrent PHY_CMN_CLK_CFG[01] | expand

Commit Message

Krzysztof Kozlowski Jan. 31, 2025, 3:02 p.m. UTC 
PHY_CMN_CLK_CFG1 register is updated by the PHY driver and by a mux
clock from Common Clock Framework:
devm_clk_hw_register_mux_parent_hws().  There could be a path leading to
concurrent and conflicting updates between PHY driver and clock
framework, e.g. changing the mux and enabling PLL clocks.

Add dedicated spinlock to be sure all PHY_CMN_CLK_CFG1 updates are
synchronized.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c | 34 +++++++++++++++++++------------
 1 file changed, 21 insertions(+), 13 deletions(-)

Comments

Dmitry Baryshkov Jan. 31, 2025, 4:25 p.m. UTC | #1 
On Fri, Jan 31, 2025 at 04:02:51PM +0100, Krzysztof Kozlowski wrote:
> PHY_CMN_CLK_CFG1 register is updated by the PHY driver and by a mux
> clock from Common Clock Framework:
> devm_clk_hw_register_mux_parent_hws().  There could be a path leading to
> concurrent and conflicting updates between PHY driver and clock
> framework, e.g. changing the mux and enabling PLL clocks.
> 
> Add dedicated spinlock to be sure all PHY_CMN_CLK_CFG1 updates are
> synchronized.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> ---
>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c | 34 +++++++++++++++++++------------
>  1 file changed, 21 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> index c164f845653816291ad96c863257f75462ef58e7..6c18b9c0e1903bbd0090aceef13ae8c6f2e080ce 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> @@ -83,6 +83,9 @@ struct dsi_pll_7nm {
>  	/* protects REG_DSI_7nm_PHY_CMN_CLK_CFG0 register */
>  	spinlock_t postdiv_lock;
>  
> +	/* protects REG_DSI_7nm_PHY_CMN_CLK_CFG1 register */
> +	spinlock_t pclk_mux_lock;
> +
>  	struct pll_7nm_cached_state cached_state;
>  
>  	struct dsi_pll_7nm *slave;
> @@ -381,22 +384,31 @@ static void dsi_pll_cmn_clk_cfg0_write(struct dsi_pll_7nm *pll, u32 val)
>  	spin_unlock_irqrestore(&pll->postdiv_lock, flags);
>  }
>  
> -static void dsi_pll_disable_global_clk(struct dsi_pll_7nm *pll)
> +static void dsi_pll_cmn_clk_cfg1_update(struct dsi_pll_7nm *pll, u32 mask,
> +					u32 val)
>  {
> +	unsigned long flags;
>  	u32 data;
>  
> +	spin_lock_irqsave(&pll->pclk_mux_lock, flags);
>  	data = readl(pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> -	writel(data & ~BIT(5), pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> +	data &= ~mask;
> +	data |= val & mask;
> +
> +	writel(data, pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> +	spin_unlock_irqrestore(&pll->pclk_mux_lock, flags);
> +}
> +
> +static void dsi_pll_disable_global_clk(struct dsi_pll_7nm *pll)
> +{
> +	dsi_pll_cmn_clk_cfg1_update(pll, BIT(5), 0);

PLease add these bits to the corresponding XML file (here and later on)

>  }
>  
>  static void dsi_pll_enable_global_clk(struct dsi_pll_7nm *pll)
>  {
> -	u32 data;
> -
>  	writel(0x04, pll->phy->base + REG_DSI_7nm_PHY_CMN_CTRL_3);
>  
> -	data = readl(pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> -	writel(data | BIT(5) | BIT(4), pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> +	dsi_pll_cmn_clk_cfg1_update(pll, BIT(5) | BIT(4), BIT(5) | BIT(4));
>  }
>  
>  static void dsi_pll_phy_dig_reset(struct dsi_pll_7nm *pll)
> @@ -574,7 +586,6 @@ static int dsi_7nm_pll_restore_state(struct msm_dsi_phy *phy)
>  {
>  	struct dsi_pll_7nm *pll_7nm = to_pll_7nm(phy->vco_hw);
>  	struct pll_7nm_cached_state *cached = &pll_7nm->cached_state;
> -	void __iomem *phy_base = pll_7nm->phy->base;
>  	u32 val;
>  	int ret;
>  
> @@ -585,11 +596,7 @@ static int dsi_7nm_pll_restore_state(struct msm_dsi_phy *phy)
>  
>  	dsi_pll_cmn_clk_cfg0_write(pll_7nm,
>  				   cached->bit_clk_div | (cached->pix_clk_div << 4));
> -
> -	val = readl(phy_base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> -	val &= ~0x3;
> -	val |= cached->pll_mux;
> -	writel(val, phy_base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> +	dsi_pll_cmn_clk_cfg1_update(pll_7nm, 0x3, cached->pll_mux);
>  
>  	ret = dsi_pll_7nm_vco_set_rate(phy->vco_hw,
>  			pll_7nm->vco_current_rate,
> @@ -742,7 +749,7 @@ static int pll_7nm_register(struct dsi_pll_7nm *pll_7nm, struct clk_hw **provide
>  					pll_by_2_bit,
>  				}), 2, 0, pll_7nm->phy->base +
>  					REG_DSI_7nm_PHY_CMN_CLK_CFG1,
> -				0, 1, 0, NULL);
> +				0, 1, 0, &pll_7nm->pclk_mux_lock);
>  		if (IS_ERR(hw)) {
>  			ret = PTR_ERR(hw);
>  			goto fail;
> @@ -787,6 +794,7 @@ static int dsi_pll_7nm_init(struct msm_dsi_phy *phy)
>  	pll_7nm_list[phy->id] = pll_7nm;
>  
>  	spin_lock_init(&pll_7nm->postdiv_lock);
> +	spin_lock_init(&pll_7nm->pclk_mux_lock);
>  
>  	pll_7nm->phy = phy;
>  
> 
> -- 
> 2.43.0
>
Krzysztof Kozlowski Feb. 3, 2025, 11:19 a.m. UTC | #2 
On 31/01/2025 17:25, Dmitry Baryshkov wrote:
>>  
>> -static void dsi_pll_disable_global_clk(struct dsi_pll_7nm *pll)
>> +static void dsi_pll_cmn_clk_cfg1_update(struct dsi_pll_7nm *pll, u32 mask,
>> +					u32 val)
>>  {
>> +	unsigned long flags;
>>  	u32 data;
>>  
>> +	spin_lock_irqsave(&pll->pclk_mux_lock, flags);
>>  	data = readl(pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
>> -	writel(data & ~BIT(5), pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
>> +	data &= ~mask;
>> +	data |= val & mask;
>> +
>> +	writel(data, pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
>> +	spin_unlock_irqrestore(&pll->pclk_mux_lock, flags);
>> +}
>> +
>> +static void dsi_pll_disable_global_clk(struct dsi_pll_7nm *pll)
>> +{
>> +	dsi_pll_cmn_clk_cfg1_update(pll, BIT(5), 0);
> 
> PLease add these bits to the corresponding XML file (here and later on)


I need some more input from you - I don't know which XML you talk about.
Do you think about:
drivers/gpu/drm/msm/registers/display/dsi_phy_7nm.xml
and others alike? But doesn't it have only register offsets, not field
offsets?


Best regards,
Krzysztof
Dmitry Baryshkov Feb. 3, 2025, 2:35 p.m. UTC | #3 
On Mon, Feb 03, 2025 at 12:19:04PM +0100, Krzysztof Kozlowski wrote:
> On 31/01/2025 17:25, Dmitry Baryshkov wrote:
> >>  
> >> -static void dsi_pll_disable_global_clk(struct dsi_pll_7nm *pll)
> >> +static void dsi_pll_cmn_clk_cfg1_update(struct dsi_pll_7nm *pll, u32 mask,
> >> +					u32 val)
> >>  {
> >> +	unsigned long flags;
> >>  	u32 data;
> >>  
> >> +	spin_lock_irqsave(&pll->pclk_mux_lock, flags);
> >>  	data = readl(pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> >> -	writel(data & ~BIT(5), pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> >> +	data &= ~mask;
> >> +	data |= val & mask;
> >> +
> >> +	writel(data, pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> >> +	spin_unlock_irqrestore(&pll->pclk_mux_lock, flags);
> >> +}
> >> +
> >> +static void dsi_pll_disable_global_clk(struct dsi_pll_7nm *pll)
> >> +{
> >> +	dsi_pll_cmn_clk_cfg1_update(pll, BIT(5), 0);
> > 
> > PLease add these bits to the corresponding XML file (here and later on)
> 
> 
> I need some more input from you - I don't know which XML you talk about.
> Do you think about:
> drivers/gpu/drm/msm/registers/display/dsi_phy_7nm.xml

Yes

> and others alike? But doesn't it have only register offsets, not field
> offsets?

It can, see for example the mdp5.xml, you can add <bitfield> under the
<reg> node. Be sure to install python3-lxml and enable
CONFIG_DRM_MSM_VALIDATE_XML if you are modifying those files.
Krzysztof Kozlowski Feb. 3, 2025, 2:38 p.m. UTC | #4 
On 03/02/2025 15:35, Dmitry Baryshkov wrote:
>>>
>>> PLease add these bits to the corresponding XML file (here and later on)
>>
>>
>> I need some more input from you - I don't know which XML you talk about.
>> Do you think about:
>> drivers/gpu/drm/msm/registers/display/dsi_phy_7nm.xml
> 
> Yes
> 
>> and others alike? But doesn't it have only register offsets, not field
>> offsets?
> 
> It can, see for example the mdp5.xml, you can add <bitfield> under the
> <reg> node. Be sure to install python3-lxml and enable
> CONFIG_DRM_MSM_VALIDATE_XML if you are modifying those files.

Ack

Best regards,
Krzysztof
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
index c164f845653816291ad96c863257f75462ef58e7..6c18b9c0e1903bbd0090aceef13ae8c6f2e080ce 100644
--- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
+++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
@@ -83,6 +83,9 @@  struct dsi_pll_7nm {
 	/* protects REG_DSI_7nm_PHY_CMN_CLK_CFG0 register */
 	spinlock_t postdiv_lock;
 
+	/* protects REG_DSI_7nm_PHY_CMN_CLK_CFG1 register */
+	spinlock_t pclk_mux_lock;
+
 	struct pll_7nm_cached_state cached_state;
 
 	struct dsi_pll_7nm *slave;
@@ -381,22 +384,31 @@  static void dsi_pll_cmn_clk_cfg0_write(struct dsi_pll_7nm *pll, u32 val)
 	spin_unlock_irqrestore(&pll->postdiv_lock, flags);
 }
 
-static void dsi_pll_disable_global_clk(struct dsi_pll_7nm *pll)
+static void dsi_pll_cmn_clk_cfg1_update(struct dsi_pll_7nm *pll, u32 mask,
+					u32 val)
 {
+	unsigned long flags;
 	u32 data;
 
+	spin_lock_irqsave(&pll->pclk_mux_lock, flags);
 	data = readl(pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
-	writel(data & ~BIT(5), pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
+	data &= ~mask;
+	data |= val & mask;
+
+	writel(data, pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
+	spin_unlock_irqrestore(&pll->pclk_mux_lock, flags);
+}
+
+static void dsi_pll_disable_global_clk(struct dsi_pll_7nm *pll)
+{
+	dsi_pll_cmn_clk_cfg1_update(pll, BIT(5), 0);
 }
 
 static void dsi_pll_enable_global_clk(struct dsi_pll_7nm *pll)
 {
-	u32 data;
-
 	writel(0x04, pll->phy->base + REG_DSI_7nm_PHY_CMN_CTRL_3);
 
-	data = readl(pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
-	writel(data | BIT(5) | BIT(4), pll->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
+	dsi_pll_cmn_clk_cfg1_update(pll, BIT(5) | BIT(4), BIT(5) | BIT(4));
 }
 
 static void dsi_pll_phy_dig_reset(struct dsi_pll_7nm *pll)
@@ -574,7 +586,6 @@  static int dsi_7nm_pll_restore_state(struct msm_dsi_phy *phy)
 {
 	struct dsi_pll_7nm *pll_7nm = to_pll_7nm(phy->vco_hw);
 	struct pll_7nm_cached_state *cached = &pll_7nm->cached_state;
-	void __iomem *phy_base = pll_7nm->phy->base;
 	u32 val;
 	int ret;
 
@@ -585,11 +596,7 @@  static int dsi_7nm_pll_restore_state(struct msm_dsi_phy *phy)
 
 	dsi_pll_cmn_clk_cfg0_write(pll_7nm,
 				   cached->bit_clk_div | (cached->pix_clk_div << 4));
-
-	val = readl(phy_base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
-	val &= ~0x3;
-	val |= cached->pll_mux;
-	writel(val, phy_base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
+	dsi_pll_cmn_clk_cfg1_update(pll_7nm, 0x3, cached->pll_mux);
 
 	ret = dsi_pll_7nm_vco_set_rate(phy->vco_hw,
 			pll_7nm->vco_current_rate,
@@ -742,7 +749,7 @@  static int pll_7nm_register(struct dsi_pll_7nm *pll_7nm, struct clk_hw **provide
 					pll_by_2_bit,
 				}), 2, 0, pll_7nm->phy->base +
 					REG_DSI_7nm_PHY_CMN_CLK_CFG1,
-				0, 1, 0, NULL);
+				0, 1, 0, &pll_7nm->pclk_mux_lock);
 		if (IS_ERR(hw)) {
 			ret = PTR_ERR(hw);
 			goto fail;
@@ -787,6 +794,7 @@  static int dsi_pll_7nm_init(struct msm_dsi_phy *phy)
 	pll_7nm_list[phy->id] = pll_7nm;
 
 	spin_lock_init(&pll_7nm->postdiv_lock);
+	spin_lock_init(&pll_7nm->pclk_mux_lock);
 
 	pll_7nm->phy = phy;