Re: [PATCH v2] drm: bridge: samsung-dsim: Fix waiting for empty cmd transfer FIFO on older Exynos

2023-08-07 Thread Marek Vasut 

On 8/7/23 15:00, Marek Szyprowski wrote:

Hi,


diff --git a/include/drm/bridge/samsung-dsim.h 
b/include/drm/bridge/samsung-dsim.h
index 05100e91ecb9..18017b3e5d9e 100644
--- a/include/drm/bridge/samsung-dsim.h
+++ b/include/drm/bridge/samsung-dsim.h
@@ -62,6 +62,7 @@ struct samsung_dsim_driver_data {
const unsigned int *reg_values;
u16 m_min;
u16 m_max;
+   unsigned int has_broken_fifoctrl_emptyhdr;


Do we want to do :1 here to allow more flags in the future ?

Like this:
unsigned int has_broken_fifoctrl_emptyhdr:1;
unsigned int another_flag:1;
...

I didn't realize this before, sorry.

[PATCH v2] drm: bridge: samsung-dsim: Fix waiting for empty cmd transfer FIFO on older Exynos

2023-08-07 Thread Marek Szyprowski 
Samsung DSIM used in older Exynos SoCs (like Exynos 4210, 4x12, 3250)
doesn't report empty level of packer header FIFO. In case of those SoCs,
use the old way of waiting for empty command tranfsfer FIFO, removed
recently by commit 14806c641582 ("Drain command transfer FIFO before
transfer").

Fixes: 14806c641582 ("drm: bridge: samsung-dsim: Drain command transfer FIFO 
before transfer")
Signed-off-by: Marek Szyprowski 
Reviewed-by: Marek Vasut 
---
v3:
- fixed 'fixes' tag, added reviewed-by

v2:
- added additional delay when workaround is used as suggested by Marek Vasut

v1: 
https://lore.kernel.org/all/20230718131859.3114135-1-m.szyprow...@samsung.com/
---
 drivers/gpu/drm/bridge/samsung-dsim.c | 18 --
 include/drm/bridge/samsung-dsim.h |  1 +
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c 
b/drivers/gpu/drm/bridge/samsung-dsim.c
index 9b7a00bafeaa..d06401de637c 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -412,6 +412,7 @@ static const struct samsung_dsim_driver_data 
exynos3_dsi_driver_data = {
.m_min = 41,
.m_max = 125,
.min_freq = 500,
+   .has_broken_fifoctrl_emptyhdr = 1,
 };
 
 static const struct samsung_dsim_driver_data exynos4_dsi_driver_data = {
@@ -428,6 +429,7 @@ static const struct samsung_dsim_driver_data 
exynos4_dsi_driver_data = {
.m_min = 41,
.m_max = 125,
.min_freq = 500,
+   .has_broken_fifoctrl_emptyhdr = 1,
 };
 
 static const struct samsung_dsim_driver_data exynos5_dsi_driver_data = {
@@ -1009,8 +1011,20 @@ static int samsung_dsim_wait_for_hdr_fifo(struct 
samsung_dsim *dsi)
do {
u32 reg = samsung_dsim_read(dsi, DSIM_FIFOCTRL_REG);
 
-   if (reg & DSIM_SFR_HEADER_EMPTY)
-   return 0;
+   if (!dsi->driver_data->has_broken_fifoctrl_emptyhdr) {
+   if (reg & DSIM_SFR_HEADER_EMPTY)
+   return 0;
+   } else {
+   if (!(reg & DSIM_SFR_HEADER_FULL)) {
+   /*
+* Wait a little bit, so the pending data can
+* actually leave the FIFO to avoid overflow.
+*/
+   if (!cond_resched())
+   usleep_range(950, 1050);
+   return 0;
+   }
+   }
 
if (!cond_resched())
usleep_range(950, 1050);
diff --git a/include/drm/bridge/samsung-dsim.h 
b/include/drm/bridge/samsung-dsim.h
index 05100e91ecb9..18017b3e5d9e 100644
--- a/include/drm/bridge/samsung-dsim.h
+++ b/include/drm/bridge/samsung-dsim.h
@@ -62,6 +62,7 @@ struct samsung_dsim_driver_data {
const unsigned int *reg_values;
u16 m_min;
u16 m_max;
+   unsigned int has_broken_fifoctrl_emptyhdr;
 };
 
 struct samsung_dsim_host_ops {
-- 
2.34.1

Re: [PATCH v2] drm: bridge: samsung-dsim: Fix waiting for empty cmd transfer FIFO on older Exynos

2023-07-21 Thread Fabio Estevam 
On Fri, Jul 21, 2023 at 8:28 AM Marek Szyprowski
 wrote:
>
> Samsung DSIM used in older Exynos SoCs (like Exynos 4210, 4x12, 3250)
> doesn't report empty level of packer header FIFO. In case of those SoCs,
> use the old way of waiting for empty command tranfsfer FIFO, removed
> recently by commit 14806c641582 ("Drain command transfer FIFO before
> transfer").
>
> Fixes: 14806c641582 ("Drain command transfer FIFO before transfer")

Nitpick: the Subject of the commit log is not complete.

Fixes: 14806c641582 ("drm: bridge: samsung-dsim: Drain command
transfer FIFO before transfer")



> Signed-off-by: Marek Szyprowski 
> ---
> v2:
> - added additional delay when workaround is used as suggested by Marek Vasut
>
> v1: 
> https://lore.kernel.org/all/20230718131859.3114135-1-m.szyprow...@samsung.com/
> ---
>  drivers/gpu/drm/bridge/samsung-dsim.c | 18 --
>  include/drm/bridge/samsung-dsim.h |  1 +
>  2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c 
> b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 9b7a00bafeaa..d06401de637c 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -412,6 +412,7 @@ static const struct samsung_dsim_driver_data 
> exynos3_dsi_driver_data = {
> .m_min = 41,
> .m_max = 125,
> .min_freq = 500,
> +   .has_broken_fifoctrl_emptyhdr = 1,
>  };
>
>  static const struct samsung_dsim_driver_data exynos4_dsi_driver_data = {
> @@ -428,6 +429,7 @@ static const struct samsung_dsim_driver_data 
> exynos4_dsi_driver_data = {
> .m_min = 41,
> .m_max = 125,
> .min_freq = 500,
> +   .has_broken_fifoctrl_emptyhdr = 1,
>  };
>
>  static const struct samsung_dsim_driver_data exynos5_dsi_driver_data = {
> @@ -1009,8 +1011,20 @@ static int samsung_dsim_wait_for_hdr_fifo(struct 
> samsung_dsim *dsi)
> do {
> u32 reg = samsung_dsim_read(dsi, DSIM_FIFOCTRL_REG);
>
> -   if (reg & DSIM_SFR_HEADER_EMPTY)
> -   return 0;
> +   if (!dsi->driver_data->has_broken_fifoctrl_emptyhdr) {
> +   if (reg & DSIM_SFR_HEADER_EMPTY)
> +   return 0;
> +   } else {
> +   if (!(reg & DSIM_SFR_HEADER_FULL)) {
> +   /*
> +* Wait a little bit, so the pending data can
> +* actually leave the FIFO to avoid overflow.
> +*/
> +   if (!cond_resched())
> +   usleep_range(950, 1050);
> +   return 0;
> +   }
> +   }
>
> if (!cond_resched())
> usleep_range(950, 1050);
> diff --git a/include/drm/bridge/samsung-dsim.h 
> b/include/drm/bridge/samsung-dsim.h
> index 05100e91ecb9..18017b3e5d9e 100644
> --- a/include/drm/bridge/samsung-dsim.h
> +++ b/include/drm/bridge/samsung-dsim.h
> @@ -62,6 +62,7 @@ struct samsung_dsim_driver_data {
> const unsigned int *reg_values;
> u16 m_min;
> u16 m_max;
> +   unsigned int has_broken_fifoctrl_emptyhdr;
>  };
>
>  struct samsung_dsim_host_ops {
> --
> 2.34.1
>

Re: [PATCH v2] drm: bridge: samsung-dsim: Fix waiting for empty cmd transfer FIFO on older Exynos

2023-07-21 Thread Marek Vasut 

On 7/21/23 13:28, Marek Szyprowski wrote:

Samsung DSIM used in older Exynos SoCs (like Exynos 4210, 4x12, 3250)
doesn't report empty level of packer header FIFO. In case of those SoCs,
use the old way of waiting for empty command tranfsfer FIFO, removed
recently by commit 14806c641582 ("Drain command transfer FIFO before
transfer").

Fixes: 14806c641582 ("Drain command transfer FIFO before transfer")
Signed-off-by: Marek Szyprowski 


Reviewed-by: Marek Vasut 

Thanks !

[PATCH v2] drm: bridge: samsung-dsim: Fix waiting for empty cmd transfer FIFO on older Exynos

2023-07-21 Thread Marek Szyprowski 
Samsung DSIM used in older Exynos SoCs (like Exynos 4210, 4x12, 3250)
doesn't report empty level of packer header FIFO. In case of those SoCs,
use the old way of waiting for empty command tranfsfer FIFO, removed
recently by commit 14806c641582 ("Drain command transfer FIFO before
transfer").

Fixes: 14806c641582 ("Drain command transfer FIFO before transfer")
Signed-off-by: Marek Szyprowski 
---
v2:
- added additional delay when workaround is used as suggested by Marek Vasut

v1: 
https://lore.kernel.org/all/20230718131859.3114135-1-m.szyprow...@samsung.com/
---
 drivers/gpu/drm/bridge/samsung-dsim.c | 18 --
 include/drm/bridge/samsung-dsim.h |  1 +
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c 
b/drivers/gpu/drm/bridge/samsung-dsim.c
index 9b7a00bafeaa..d06401de637c 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -412,6 +412,7 @@ static const struct samsung_dsim_driver_data 
exynos3_dsi_driver_data = {
.m_min = 41,
.m_max = 125,
.min_freq = 500,
+   .has_broken_fifoctrl_emptyhdr = 1,
 };
 
 static const struct samsung_dsim_driver_data exynos4_dsi_driver_data = {
@@ -428,6 +429,7 @@ static const struct samsung_dsim_driver_data 
exynos4_dsi_driver_data = {
.m_min = 41,
.m_max = 125,
.min_freq = 500,
+   .has_broken_fifoctrl_emptyhdr = 1,
 };
 
 static const struct samsung_dsim_driver_data exynos5_dsi_driver_data = {
@@ -1009,8 +1011,20 @@ static int samsung_dsim_wait_for_hdr_fifo(struct 
samsung_dsim *dsi)
do {
u32 reg = samsung_dsim_read(dsi, DSIM_FIFOCTRL_REG);
 
-   if (reg & DSIM_SFR_HEADER_EMPTY)
-   return 0;
+   if (!dsi->driver_data->has_broken_fifoctrl_emptyhdr) {
+   if (reg & DSIM_SFR_HEADER_EMPTY)
+   return 0;
+   } else {
+   if (!(reg & DSIM_SFR_HEADER_FULL)) {
+   /*
+* Wait a little bit, so the pending data can
+* actually leave the FIFO to avoid overflow.
+*/
+   if (!cond_resched())
+   usleep_range(950, 1050);
+   return 0;
+   }
+   }
 
if (!cond_resched())
usleep_range(950, 1050);
diff --git a/include/drm/bridge/samsung-dsim.h 
b/include/drm/bridge/samsung-dsim.h
index 05100e91ecb9..18017b3e5d9e 100644
--- a/include/drm/bridge/samsung-dsim.h
+++ b/include/drm/bridge/samsung-dsim.h
@@ -62,6 +62,7 @@ struct samsung_dsim_driver_data {
const unsigned int *reg_values;
u16 m_min;
u16 m_max;
+   unsigned int has_broken_fifoctrl_emptyhdr;
 };
 
 struct samsung_dsim_host_ops {
-- 
2.34.1