[PATCH] ARM: rockchip: restore dapswjdp after suspend

[PATCH] ARM: rockchip: restore dapswjdp after suspend

[Doug Anderson]

In the commit (0ea001d ARM: rockchip: disable dapswjdp during suspend)
we made the assumption that we didn't need to restore dapswjdp after
suspend because "the MASKROM will enable it back".

It turns out that's not a safe assumption.  In some cases (pending
interrupts) it's possible that the WFI might act as a no-op and the
MaskROM will never run.  Since we're changing the bit, we should
restore it ourselves.

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
 arch/arm/mach-rockchip/pm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/mach-rockchip/pm.c b/arch/arm/mach-rockchip/pm.c
index b0dcbe2..a7be465 100644
--- a/arch/arm/mach-rockchip/pm.c
+++ b/arch/arm/mach-rockchip/pm.c
@@ -48,6 +48,7 @@ static struct regmap *sgrf_regmap;
 
 static u32 rk3288_pmu_pwr_mode_con;
 static u32 rk3288_sgrf_soc_con0;
+static u32 rk3288_sgrf_cpu_con0;
 
 static inline u32 rk3288_l2_config(void)
 {
@@ -70,6 +71,7 @@ static void rk3288_slp_mode_set(int level)
 {
 	u32 mode_set, mode_set1;
 
+	regmap_read(sgrf_regmap, RK3288_SGRF_CPU_CON0, &rk3288_sgrf_cpu_con0);
 	regmap_read(sgrf_regmap, RK3288_SGRF_SOC_CON0, &rk3288_sgrf_soc_con0);
 
 	regmap_read(pmu_regmap, RK3288_PMU_PWRMODE_CON,
@@ -129,6 +131,9 @@ static void rk3288_slp_mode_set(int level)
 
 static void rk3288_slp_mode_set_resume(void)
 {
+	regmap_write(sgrf_regmap, RK3288_SGRF_CPU_CON0,
+		     rk3288_sgrf_cpu_con0 | SGRF_DAPDEVICEEN_WRITE);
+
 	regmap_write(pmu_regmap, RK3288_PMU_PWRMODE_CON,
 		     rk3288_pmu_pwr_mode_con);
 
-- 
2.2.0.rc0.207.ga3a616c

[PATCH] ARM: rockchip: restore dapswjdp after suspend

[Chris Zhong]

Hi Doug

Thank you for pointing out.

Reviewed-by: Chris Zhong <zyw@rock-chips.com>

On 05/21/2015 04:34 AM, Doug Anderson wrote:
> In the commit (0ea001d ARM: rockchip: disable dapswjdp during suspend)
> we made the assumption that we didn't need to restore dapswjdp after
> suspend because "the MASKROM will enable it back".
>
> It turns out that's not a safe assumption.  In some cases (pending
> interrupts) it's possible that the WFI might act as a no-op and the
> MaskROM will never run.  Since we're changing the bit, we should
> restore it ourselves.
>
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
>   arch/arm/mach-rockchip/pm.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/arch/arm/mach-rockchip/pm.c b/arch/arm/mach-rockchip/pm.c
> index b0dcbe2..a7be465 100644
> --- a/arch/arm/mach-rockchip/pm.c
> +++ b/arch/arm/mach-rockchip/pm.c
> @@ -48,6 +48,7 @@ static struct regmap *sgrf_regmap;
>   
>   static u32 rk3288_pmu_pwr_mode_con;
>   static u32 rk3288_sgrf_soc_con0;
> +static u32 rk3288_sgrf_cpu_con0;
>   
>   static inline u32 rk3288_l2_config(void)
>   {
> @@ -70,6 +71,7 @@ static void rk3288_slp_mode_set(int level)
>   {
>   	u32 mode_set, mode_set1;
>   
> +	regmap_read(sgrf_regmap, RK3288_SGRF_CPU_CON0, &rk3288_sgrf_cpu_con0);
>   	regmap_read(sgrf_regmap, RK3288_SGRF_SOC_CON0, &rk3288_sgrf_soc_con0);
>   
>   	regmap_read(pmu_regmap, RK3288_PMU_PWRMODE_CON,
> @@ -129,6 +131,9 @@ static void rk3288_slp_mode_set(int level)
>   
>   static void rk3288_slp_mode_set_resume(void)
>   {
> +	regmap_write(sgrf_regmap, RK3288_SGRF_CPU_CON0,
> +		     rk3288_sgrf_cpu_con0 | SGRF_DAPDEVICEEN_WRITE);
> +
>   	regmap_write(pmu_regmap, RK3288_PMU_PWRMODE_CON,
>   		     rk3288_pmu_pwr_mode_con);
>   

[PATCH] ARM: rockchip: restore dapswjdp after suspend

[Huang, Tao]

Hi, Doug:

? 2015?05?21? 04:34, Doug Anderson ??:
> In the commit (0ea001d ARM: rockchip: disable dapswjdp during suspend)
> we made the assumption that we didn't need to restore dapswjdp after
> suspend because "the MASKROM will enable it back".
> 
> It turns out that's not a safe assumption.  In some cases (pending
> interrupts) it's possible that the WFI might act as a no-op and the
> MaskROM will never run.


I don't think this can happen. It seems we set PMU_GLOBAL_INT_DISABLE
bit, which means in power off flow, the IRQ will not accepted until the
ARM is power off. Do you see the SGRF_CPU_CON0[0] is 0 after resume?

Anyway, restore the value is okay, which make the code more symmetrically



  Since we're changing the bit, we should
> restore it ourselves.
> 
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
>  arch/arm/mach-rockchip/pm.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm/mach-rockchip/pm.c b/arch/arm/mach-rockchip/pm.c
> index b0dcbe2..a7be465 100644
> --- a/arch/arm/mach-rockchip/pm.c
> +++ b/arch/arm/mach-rockchip/pm.c
> @@ -48,6 +48,7 @@ static struct regmap *sgrf_regmap;
>  
>  static u32 rk3288_pmu_pwr_mode_con;
>  static u32 rk3288_sgrf_soc_con0;
> +static u32 rk3288_sgrf_cpu_con0;
>  
>  static inline u32 rk3288_l2_config(void)
>  {
> @@ -70,6 +71,7 @@ static void rk3288_slp_mode_set(int level)
>  {
>  	u32 mode_set, mode_set1;
>  
> +	regmap_read(sgrf_regmap, RK3288_SGRF_CPU_CON0, &rk3288_sgrf_cpu_con0);
>  	regmap_read(sgrf_regmap, RK3288_SGRF_SOC_CON0, &rk3288_sgrf_soc_con0);
>  
>  	regmap_read(pmu_regmap, RK3288_PMU_PWRMODE_CON,
> @@ -129,6 +131,9 @@ static void rk3288_slp_mode_set(int level)
>  
>  static void rk3288_slp_mode_set_resume(void)
>  {
> +	regmap_write(sgrf_regmap, RK3288_SGRF_CPU_CON0,
> +		     rk3288_sgrf_cpu_con0 | SGRF_DAPDEVICEEN_WRITE);
> +
>  	regmap_write(pmu_regmap, RK3288_PMU_PWRMODE_CON,
>  		     rk3288_pmu_pwr_mode_con);
>  
> 

[PATCH] ARM: rockchip: restore dapswjdp after suspend

[Doug Anderson]

Huang Tao,

On Wed, May 20, 2015 at 7:02 PM, Huang, Tao <huangtao@rock-chips.com> wrote:
>> It turns out that's not a safe assumption.  In some cases (pending
>> interrupts) it's possible that the WFI might act as a no-op and the
>> MaskROM will never run.
>
>
> I don't think this can happen. It seems we set PMU_GLOBAL_INT_DISABLE
> bit, which means in power off flow, the IRQ will not accepted until the
> ARM is power off. Do you see the SGRF_CPU_CON0[0] is 0 after resume?

>From testing, it appears that it can happen that the WFI might act as a no-op.

...but you're right in pointing out that unless we can solve the
PMU_GLOBAL_INT_DISABLE() problem then this patch here to fix
DAPDEVICEEN isn't too useful.  I was hoping to fix the
PMU_GLOBAL_INT_DISABLE() in
<https://chromium-review.googlesource.com/#/c/272442/> or find a
similar solution.  ...if we can's solve that though, then I'm not sure
what to suggest.


> Anyway, restore the value is okay, which make the code more symmetrically

OK.  Heiko: applying this won't hurt, but it will only be useful if we
find a way to return from the WFI successfully...

-Doug

[PATCH] ARM: rockchip: restore dapswjdp after suspend

[Heiko Stuebner]

Hi Doug,

Am Donnerstag, 21. Mai 2015, 08:40:55 schrieb Doug Anderson:
> On Wed, May 20, 2015 at 7:02 PM, Huang, Tao <huangtao@rock-chips.com> wrote:
> >> It turns out that's not a safe assumption.  In some cases (pending
> >> interrupts) it's possible that the WFI might act as a no-op and the
> >> MaskROM will never run.
> > Anyway, restore the value is okay, which make the code more symmetrically
> 
> OK.  Heiko: applying this won't hurt, but it will only be useful if we
> find a way to return from the WFI successfully...

As it looks sane but doesn't fix an immediate problem I have applied this to my 
soc-branch for 4.2 .


Thanks
Heiko