diff mbox

[RESEND] pm: at91: Workaround DDRSDRC self-refresh bug with LPDDR1 memories

Message ID 1421241632-2991-1-git-send-email-peda@lysator.liu.se (mailing list archive)
State New, archived
Headers show

Commit Message

Peter Rosin Jan. 14, 2015, 1:20 p.m. UTC
From: Peter Rosin <peda@axentia.se>

The DDRSDR controller (on the ATSAMA5D31) fails miserably to put LPDDR1
memories in self-refresh. Force the controller to think it has DDR2
memories during the self-refresh period, as the DDR2 self-refresh spec
is equivalent to LPDDR1, and is correctly implemented in the controller.

Assume that the second controller has the same fault, and that other
CPUs in the family has the same problem, but that is untested.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 arch/arm/mach-at91/pm_slowclock.S  |   43 +++++++++++++++++++++++++++++++-----
 include/soc/at91/at91sam9_ddrsdr.h |    2 +-
 2 files changed, 39 insertions(+), 6 deletions(-)

Comments

Nicolas Ferre Jan. 14, 2015, 4:47 p.m. UTC | #1
Le 14/01/2015 14:20, Peter Rosin a écrit :
> From: Peter Rosin <peda@axentia.se>
> 
> The DDRSDR controller (on the ATSAMA5D31) fails miserably to put LPDDR1
> memories in self-refresh. Force the controller to think it has DDR2
> memories during the self-refresh period, as the DDR2 self-refresh spec
> is equivalent to LPDDR1, and is correctly implemented in the controller.
> 
> Assume that the second controller has the same fault, and that other
> CPUs in the family has the same problem, but that is untested.
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>

I've just verified your code and the scope of this issue and your
implementation makes perfect sense.

Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>

Peter,
Thanks for your patch. You will probably see it appearing in 3.20 or 3.21.

Wenyou,
Can you please integrate the patch from Peter in your current rework of
the PM routines (keeping his authorship of course)?
Please tell me if I can help with this.

Best regards,


> ---
>  arch/arm/mach-at91/pm_slowclock.S  |   43 +++++++++++++++++++++++++++++++-----
>  include/soc/at91/at91sam9_ddrsdr.h |    2 +-
>  2 files changed, 39 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/mach-at91/pm_slowclock.S b/arch/arm/mach-at91/pm_slowclock.S
> index 20018779bae7..63a9e0b0a17d 100644
> --- a/arch/arm/mach-at91/pm_slowclock.S
> +++ b/arch/arm/mach-at91/pm_slowclock.S
> @@ -143,6 +143,16 @@ ddr_sr_enable:
>  	cmp	memctrl, #AT91_MEMCTRL_DDRSDR
>  	bne	sdr_sr_enable
>  
> +	/* LPDDR1 --> force DDR2 mode during self-refresh */
> +	ldr	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
> +	str	tmp1, .saved_sam9_mdr
> +	bic	tmp1, tmp1, #~AT91_DDRSDRC_MD
> +	cmp	tmp1, #AT91_DDRSDRC_MD_LOW_POWER_DDR
> +	ldreq	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
> +	biceq	tmp1, tmp1, #AT91_DDRSDRC_MD
> +	orreq	tmp1, tmp1, #AT91_DDRSDRC_MD_DDR2
> +	streq	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
> +
>  	/* prepare for DDRAM self-refresh mode */
>  	ldr	tmp1, [sdramc, #AT91_DDRSDRC_LPR]
>  	str	tmp1, .saved_sam9_lpr
> @@ -151,14 +161,26 @@ ddr_sr_enable:
>  
>  	/* figure out if we use the second ram controller */
>  	cmp	ramc1, #0
> -	ldrne	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
> -	strne	tmp2, .saved_sam9_lpr1
> -	bicne	tmp2, #AT91_DDRSDRC_LPCB
> -	orrne	tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH
> +	beq	ddr_no_2nd_ctrl
> +
> +	ldr	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
> +	str	tmp2, .saved_sam9_mdr1
> +	bic	tmp2, tmp2, #~AT91_DDRSDRC_MD
> +	cmp	tmp2, #AT91_DDRSDRC_MD_LOW_POWER_DDR
> +	ldreq	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
> +	biceq	tmp2, tmp2, #AT91_DDRSDRC_MD
> +	orreq	tmp2, tmp2, #AT91_DDRSDRC_MD_DDR2
> +	streq	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
> +
> +	ldr	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
> +	str	tmp2, .saved_sam9_lpr1
> +	bic	tmp2, #AT91_DDRSDRC_LPCB
> +	orr	tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH
>  
>  	/* Enable DDRAM self-refresh mode */
> +	str	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
> +ddr_no_2nd_ctrl:
>  	str	tmp1, [sdramc, #AT91_DDRSDRC_LPR]
> -	strne	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
>  
>  	b	sdr_sr_done
>  
> @@ -289,12 +311,17 @@ sdr_sr_done:
>  	 */
>  	cmp	memctrl, #AT91_MEMCTRL_DDRSDR
>  	bne	sdr_en_restore
> +	/* Restore MDR in case of LPDDR1 */
> +	ldr	tmp1, .saved_sam9_mdr
> +	str	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
>  	/* Restore LPR on AT91 with DDRAM */
>  	ldr	tmp1, .saved_sam9_lpr
>  	str	tmp1, [sdramc, #AT91_DDRSDRC_LPR]
>  
>  	/* if we use the second ram controller */
>  	cmp	ramc1, #0
> +	ldrne	tmp2, .saved_sam9_mdr1
> +	strne	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
>  	ldrne	tmp2, .saved_sam9_lpr1
>  	strne	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
>  
> @@ -328,5 +355,11 @@ ram_restored:
>  .saved_sam9_lpr1:
>  	.word 0
>  
> +.saved_sam9_mdr:
> +	.word 0
> +
> +.saved_sam9_mdr1:
> +	.word 0
> +
>  ENTRY(at91_slow_clock_sz)
>  	.word .-at91_slow_clock
> diff --git a/include/soc/at91/at91sam9_ddrsdr.h b/include/soc/at91/at91sam9_ddrsdr.h
> index 0210797abf2e..cd2c18787833 100644
> --- a/include/soc/at91/at91sam9_ddrsdr.h
> +++ b/include/soc/at91/at91sam9_ddrsdr.h
> @@ -92,7 +92,7 @@
>  #define		AT91_DDRSDRC_UPD_MR	(3 << 20)	 /* Update load mode register and extended mode register */
>  
>  #define AT91_DDRSDRC_MDR	0x20	/* Memory Device Register */
> -#define		AT91_DDRSDRC_MD		(3 << 0)		/* Memory Device Type */
> +#define		AT91_DDRSDRC_MD		(7 << 0)		/* Memory Device Type */
>  #define			AT91_DDRSDRC_MD_SDR		0
>  #define			AT91_DDRSDRC_MD_LOW_POWER_SDR	1
>  #define			AT91_DDRSDRC_MD_LOW_POWER_DDR	3
>
Peter Rosin Jan. 14, 2015, 9:33 p.m. UTC | #2
Nicolas Ferre wrote:
> Le 14/01/2015 14:20, Peter Rosin a écrit :
> > From: Peter Rosin <peda@axentia.se>
> >
> > The DDRSDR controller (on the ATSAMA5D31) fails miserably to put
> > LPDDR1 memories in self-refresh. Force the controller to think it has
> > DDR2 memories during the self-refresh period, as the DDR2 self-refresh
> > spec is equivalent to LPDDR1, and is correctly implemented in the
> controller.
> >
> > Assume that the second controller has the same fault, and that other
> > CPUs in the family has the same problem, but that is untested.
> >
> > Signed-off-by: Peter Rosin <peda@axentia.se>
> 
> I've just verified your code and the scope of this issue and your
> implementation makes perfect sense.
> 
> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> 
> Peter,
> Thanks for your patch. You will probably see it appearing in 3.20 or 3.21.

Great!

> Wenyou,
> Can you please integrate the patch from Peter in your current rework of the
> PM routines (keeping his authorship of course)?
> Please tell me if I can help with this.

To be 100% honest with credits, I should perhaps have mentioned that I
received an unconditional proof-of-concept patch from Atmel support
(Case 00007347). I'm not certain who wrote that patch, but the only thing
that has survived is the idea to temporarily use DDR2 mode and the trivial
change of the register field width in the header file. So, I do not feel too
dishonest by claiming authorship...

Cheers,
Peter
Wenyou Yang Jan. 15, 2015, 5:54 a.m. UTC | #3
> -----Original Message-----
> From: Ferre, Nicolas
> Sent: Thursday, January 15, 2015 12:48 AM
> To: Peter Rosin; linux-arm-kernel@lists.infradead.org; Yang, Wenyou
> Cc: Peter Rosin; Andrew Victor; Jean-Christophe Plagniol-Villard; Russell King;
> linux-kernel@vger.kernel.org; Alexandre Belloni; Boris BREZILLON
> Subject: Re: [PATCH RESEND] pm: at91: Workaround DDRSDRC self-refresh bug
> with LPDDR1 memories
> 
> Le 14/01/2015 14:20, Peter Rosin a écrit :
> > From: Peter Rosin <peda@axentia.se>
> >
> > The DDRSDR controller (on the ATSAMA5D31) fails miserably to put
> > LPDDR1 memories in self-refresh. Force the controller to think it has
> > DDR2 memories during the self-refresh period, as the DDR2 self-refresh
> > spec is equivalent to LPDDR1, and is correctly implemented in the controller.
> >
> > Assume that the second controller has the same fault, and that other
> > CPUs in the family has the same problem, but that is untested.
> >
> > Signed-off-by: Peter Rosin <peda@axentia.se>
> 
> I've just verified your code and the scope of this issue and your implementation
> makes perfect sense.
> 
> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> 
> Peter,
> Thanks for your patch. You will probably see it appearing in 3.20 or 3.21.
> 
> Wenyou,
> Can you please integrate the patch from Peter in your current rework of the PM
> routines (keeping his authorship of course)?
Of course, I will integrate.

> Please tell me if I can help with this.
> 
> Best regards,
> 
> 
> > ---
> >  arch/arm/mach-at91/pm_slowclock.S  |   43
> +++++++++++++++++++++++++++++++-----
> >  include/soc/at91/at91sam9_ddrsdr.h |    2 +-
> >  2 files changed, 39 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/arm/mach-at91/pm_slowclock.S
> > b/arch/arm/mach-at91/pm_slowclock.S
> > index 20018779bae7..63a9e0b0a17d 100644
> > --- a/arch/arm/mach-at91/pm_slowclock.S
> > +++ b/arch/arm/mach-at91/pm_slowclock.S
> > @@ -143,6 +143,16 @@ ddr_sr_enable:
> >  	cmp	memctrl, #AT91_MEMCTRL_DDRSDR
> >  	bne	sdr_sr_enable
> >
> > +	/* LPDDR1 --> force DDR2 mode during self-refresh */
> > +	ldr	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
> > +	str	tmp1, .saved_sam9_mdr
> > +	bic	tmp1, tmp1, #~AT91_DDRSDRC_MD
> > +	cmp	tmp1, #AT91_DDRSDRC_MD_LOW_POWER_DDR
> > +	ldreq	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
> > +	biceq	tmp1, tmp1, #AT91_DDRSDRC_MD
> > +	orreq	tmp1, tmp1, #AT91_DDRSDRC_MD_DDR2
> > +	streq	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
> > +
> >  	/* prepare for DDRAM self-refresh mode */
> >  	ldr	tmp1, [sdramc, #AT91_DDRSDRC_LPR]
> >  	str	tmp1, .saved_sam9_lpr
> > @@ -151,14 +161,26 @@ ddr_sr_enable:
> >
> >  	/* figure out if we use the second ram controller */
> >  	cmp	ramc1, #0
> > -	ldrne	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
> > -	strne	tmp2, .saved_sam9_lpr1
> > -	bicne	tmp2, #AT91_DDRSDRC_LPCB
> > -	orrne	tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH
> > +	beq	ddr_no_2nd_ctrl
> > +
> > +	ldr	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
> > +	str	tmp2, .saved_sam9_mdr1
> > +	bic	tmp2, tmp2, #~AT91_DDRSDRC_MD
> > +	cmp	tmp2, #AT91_DDRSDRC_MD_LOW_POWER_DDR
> > +	ldreq	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
> > +	biceq	tmp2, tmp2, #AT91_DDRSDRC_MD
> > +	orreq	tmp2, tmp2, #AT91_DDRSDRC_MD_DDR2
> > +	streq	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
> > +
> > +	ldr	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
> > +	str	tmp2, .saved_sam9_lpr1
> > +	bic	tmp2, #AT91_DDRSDRC_LPCB
> > +	orr	tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH
> >
> >  	/* Enable DDRAM self-refresh mode */
> > +	str	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
> > +ddr_no_2nd_ctrl:
> >  	str	tmp1, [sdramc, #AT91_DDRSDRC_LPR]
> > -	strne	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
> >
> >  	b	sdr_sr_done
> >
> > @@ -289,12 +311,17 @@ sdr_sr_done:
> >  	 */
> >  	cmp	memctrl, #AT91_MEMCTRL_DDRSDR
> >  	bne	sdr_en_restore
> > +	/* Restore MDR in case of LPDDR1 */
> > +	ldr	tmp1, .saved_sam9_mdr
> > +	str	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
> >  	/* Restore LPR on AT91 with DDRAM */
> >  	ldr	tmp1, .saved_sam9_lpr
> >  	str	tmp1, [sdramc, #AT91_DDRSDRC_LPR]
> >
> >  	/* if we use the second ram controller */
> >  	cmp	ramc1, #0
> > +	ldrne	tmp2, .saved_sam9_mdr1
> > +	strne	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
> >  	ldrne	tmp2, .saved_sam9_lpr1
> >  	strne	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
> >
> > @@ -328,5 +355,11 @@ ram_restored:
> >  .saved_sam9_lpr1:
> >  	.word 0
> >
> > +.saved_sam9_mdr:
> > +	.word 0
> > +
> > +.saved_sam9_mdr1:
> > +	.word 0
> > +
> >  ENTRY(at91_slow_clock_sz)
> >  	.word .-at91_slow_clock
> > diff --git a/include/soc/at91/at91sam9_ddrsdr.h
> > b/include/soc/at91/at91sam9_ddrsdr.h
> > index 0210797abf2e..cd2c18787833 100644
> > --- a/include/soc/at91/at91sam9_ddrsdr.h
> > +++ b/include/soc/at91/at91sam9_ddrsdr.h
> > @@ -92,7 +92,7 @@
> >  #define		AT91_DDRSDRC_UPD_MR	(3 << 20)	 /* Update
> load mode register and extended mode register */
> >
> >  #define AT91_DDRSDRC_MDR	0x20	/* Memory Device Register */
> > -#define		AT91_DDRSDRC_MD		(3 << 0)		/* Memory
> Device Type */
> > +#define		AT91_DDRSDRC_MD		(7 << 0)		/* Memory
> Device Type */
> >  #define			AT91_DDRSDRC_MD_SDR		0
> >  #define			AT91_DDRSDRC_MD_LOW_POWER_SDR	1
> >  #define			AT91_DDRSDRC_MD_LOW_POWER_DDR	3
> >
> 
> 
> --
> Nicolas Ferre

Best Regards,
Wenyou Yang
diff mbox

Patch

diff --git a/arch/arm/mach-at91/pm_slowclock.S b/arch/arm/mach-at91/pm_slowclock.S
index 20018779bae7..63a9e0b0a17d 100644
--- a/arch/arm/mach-at91/pm_slowclock.S
+++ b/arch/arm/mach-at91/pm_slowclock.S
@@ -143,6 +143,16 @@  ddr_sr_enable:
 	cmp	memctrl, #AT91_MEMCTRL_DDRSDR
 	bne	sdr_sr_enable
 
+	/* LPDDR1 --> force DDR2 mode during self-refresh */
+	ldr	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
+	str	tmp1, .saved_sam9_mdr
+	bic	tmp1, tmp1, #~AT91_DDRSDRC_MD
+	cmp	tmp1, #AT91_DDRSDRC_MD_LOW_POWER_DDR
+	ldreq	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
+	biceq	tmp1, tmp1, #AT91_DDRSDRC_MD
+	orreq	tmp1, tmp1, #AT91_DDRSDRC_MD_DDR2
+	streq	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
+
 	/* prepare for DDRAM self-refresh mode */
 	ldr	tmp1, [sdramc, #AT91_DDRSDRC_LPR]
 	str	tmp1, .saved_sam9_lpr
@@ -151,14 +161,26 @@  ddr_sr_enable:
 
 	/* figure out if we use the second ram controller */
 	cmp	ramc1, #0
-	ldrne	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
-	strne	tmp2, .saved_sam9_lpr1
-	bicne	tmp2, #AT91_DDRSDRC_LPCB
-	orrne	tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH
+	beq	ddr_no_2nd_ctrl
+
+	ldr	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
+	str	tmp2, .saved_sam9_mdr1
+	bic	tmp2, tmp2, #~AT91_DDRSDRC_MD
+	cmp	tmp2, #AT91_DDRSDRC_MD_LOW_POWER_DDR
+	ldreq	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
+	biceq	tmp2, tmp2, #AT91_DDRSDRC_MD
+	orreq	tmp2, tmp2, #AT91_DDRSDRC_MD_DDR2
+	streq	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
+
+	ldr	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
+	str	tmp2, .saved_sam9_lpr1
+	bic	tmp2, #AT91_DDRSDRC_LPCB
+	orr	tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH
 
 	/* Enable DDRAM self-refresh mode */
+	str	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
+ddr_no_2nd_ctrl:
 	str	tmp1, [sdramc, #AT91_DDRSDRC_LPR]
-	strne	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
 
 	b	sdr_sr_done
 
@@ -289,12 +311,17 @@  sdr_sr_done:
 	 */
 	cmp	memctrl, #AT91_MEMCTRL_DDRSDR
 	bne	sdr_en_restore
+	/* Restore MDR in case of LPDDR1 */
+	ldr	tmp1, .saved_sam9_mdr
+	str	tmp1, [sdramc, #AT91_DDRSDRC_MDR]
 	/* Restore LPR on AT91 with DDRAM */
 	ldr	tmp1, .saved_sam9_lpr
 	str	tmp1, [sdramc, #AT91_DDRSDRC_LPR]
 
 	/* if we use the second ram controller */
 	cmp	ramc1, #0
+	ldrne	tmp2, .saved_sam9_mdr1
+	strne	tmp2, [ramc1, #AT91_DDRSDRC_MDR]
 	ldrne	tmp2, .saved_sam9_lpr1
 	strne	tmp2, [ramc1, #AT91_DDRSDRC_LPR]
 
@@ -328,5 +355,11 @@  ram_restored:
 .saved_sam9_lpr1:
 	.word 0
 
+.saved_sam9_mdr:
+	.word 0
+
+.saved_sam9_mdr1:
+	.word 0
+
 ENTRY(at91_slow_clock_sz)
 	.word .-at91_slow_clock
diff --git a/include/soc/at91/at91sam9_ddrsdr.h b/include/soc/at91/at91sam9_ddrsdr.h
index 0210797abf2e..cd2c18787833 100644
--- a/include/soc/at91/at91sam9_ddrsdr.h
+++ b/include/soc/at91/at91sam9_ddrsdr.h
@@ -92,7 +92,7 @@ 
 #define		AT91_DDRSDRC_UPD_MR	(3 << 20)	 /* Update load mode register and extended mode register */
 
 #define AT91_DDRSDRC_MDR	0x20	/* Memory Device Register */
-#define		AT91_DDRSDRC_MD		(3 << 0)		/* Memory Device Type */
+#define		AT91_DDRSDRC_MD		(7 << 0)		/* Memory Device Type */
 #define			AT91_DDRSDRC_MD_SDR		0
 #define			AT91_DDRSDRC_MD_LOW_POWER_SDR	1
 #define			AT91_DDRSDRC_MD_LOW_POWER_DDR	3