Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Philippe CORNU]

Many thanks
Philippe :-)

On 02/08/2018 08:39 AM, Andrzej Hajda wrote:
> On 04.02.2018 22:31, Philippe Cornu wrote:
>> This patch adds the DCS/GENERIC DSI read feature.
>>
>> Signed-off-by: Philippe Cornu 
>> ---
> Queued to drm-misc-next.
> --
> Regards
> Andrzej
> 

Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Philippe CORNU]

Many thanks
Philippe :-)

On 02/08/2018 08:39 AM, Andrzej Hajda wrote:
> On 04.02.2018 22:31, Philippe Cornu wrote:
>> This patch adds the DCS/GENERIC DSI read feature.
>>
>> Signed-off-by: Philippe Cornu 
>> ---
> Queued to drm-misc-next.
> --
> Regards
> Andrzej
> 

Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Andrzej Hajda]

On 04.02.2018 22:31, Philippe Cornu wrote:
> This patch adds the DCS/GENERIC DSI read feature.
>
> Signed-off-by: Philippe Cornu 
> ---
Queued to drm-misc-next.
--
Regards
Andrzej

Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Andrzej Hajda]

On 04.02.2018 22:31, Philippe Cornu wrote:
> This patch adds the DCS/GENERIC DSI read feature.
>
> Signed-off-by: Philippe Cornu 
> ---
Queued to drm-misc-next.
--
Regards
Andrzej

Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Brian Norris]

Hi,

On Sun, Feb 04, 2018 at 10:31:04PM +0100, Philippe Cornu wrote:
> This patch adds the DCS/GENERIC DSI read feature.
> 
> Signed-off-by: Philippe Cornu 
> ---
> Extra notes:
> DSI read tests have been performed with DCS & GENERIC, short & long
> commands, on two different panels.
> The maximum fifo size (32*32-bit = 128 bytes on stm32) has been
> verified too.

Seems OK to me, just comparing with work we've been borrowing from
Rockchip:

https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/863347

(And in fact, it looks much better than that.)

So FWIW:

Reviewed-by: Brian Norris 

and thanks a bunch!

Brian

>  drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 
> +--
>  1 file changed, 45 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index e9422d05e897..65aeb3f78b48 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
>   return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
>  }
>  
> +static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
> + const struct mipi_dsi_msg *msg)
> +{
> + int i, j, ret, len = msg->rx_len;
> + u8 *buf = msg->rx_buf;
> + u32 val;
> +
> + /* Wait end of the read operation */
> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +  val, !(val & GEN_RD_CMD_BUSY),
> +  1000, CMD_PKT_STATUS_TIMEOUT_US);
> + if (ret) {
> + dev_err(dsi->dev, "Timeout during read operation\n");
> + return ret;
> + }
> +
> + for (i = 0; i < len; i += 4) {
> + /* Read fifo must not be empty before all bytes are read */
> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +  val, !(val & GEN_PLD_R_EMPTY),
> +  1000, CMD_PKT_STATUS_TIMEOUT_US);
> + if (ret) {
> + dev_err(dsi->dev, "Read payload FIFO is empty\n");
> + return ret;
> + }
> +
> + val = dsi_read(dsi, DSI_GEN_PLD_DATA);
> + for (j = 0; j < 4 && j + i < len; j++)
> + buf[i + j] = val >> (8 * j);
> + }
> +
> + return ret;
> +}
> +
>  static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>const struct mipi_dsi_msg *msg)
>  {
>   struct dw_mipi_dsi *dsi = host_to_dsi(host);
>   struct mipi_dsi_packet packet;
> - int ret;
> -
> - if (msg->rx_buf || msg->rx_len) {
> - /* TODO dw drv improvements: implement read feature */
> - dev_warn(dsi->dev, "read operations not yet implemented\n");
> - return -EINVAL;
> - }
> + int ret, nb_bytes;
>  
>   ret = mipi_dsi_create_packet(, msg);
>   if (ret) {
> @@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct 
> mipi_dsi_host *host,
>   if (ret)
>   return ret;
>  
> - /*
> -  * TODO Only transmitted size is returned as actual driver does
> -  * not support dcs/generic reads. Please update return value when
> -  * delivering the read feature.
> -  */
> - return packet.size;
> + if (msg->rx_buf && msg->rx_len) {
> + ret = dw_mipi_dsi_read(dsi, msg);
> + if (ret)
> + return ret;
> + nb_bytes = msg->rx_len;
> + } else {
> + nb_bytes = packet.size;
> + }
> +
> + return nb_bytes;
>  }
>  
>  static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
> -- 
> 2.15.1
> 

Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Brian Norris]

Hi,

On Sun, Feb 04, 2018 at 10:31:04PM +0100, Philippe Cornu wrote:
> This patch adds the DCS/GENERIC DSI read feature.
> 
> Signed-off-by: Philippe Cornu 
> ---
> Extra notes:
> DSI read tests have been performed with DCS & GENERIC, short & long
> commands, on two different panels.
> The maximum fifo size (32*32-bit = 128 bytes on stm32) has been
> verified too.

Seems OK to me, just comparing with work we've been borrowing from
Rockchip:

https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/863347

(And in fact, it looks much better than that.)

So FWIW:

Reviewed-by: Brian Norris 

and thanks a bunch!

Brian

>  drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 
> +--
>  1 file changed, 45 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index e9422d05e897..65aeb3f78b48 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
>   return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
>  }
>  
> +static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
> + const struct mipi_dsi_msg *msg)
> +{
> + int i, j, ret, len = msg->rx_len;
> + u8 *buf = msg->rx_buf;
> + u32 val;
> +
> + /* Wait end of the read operation */
> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +  val, !(val & GEN_RD_CMD_BUSY),
> +  1000, CMD_PKT_STATUS_TIMEOUT_US);
> + if (ret) {
> + dev_err(dsi->dev, "Timeout during read operation\n");
> + return ret;
> + }
> +
> + for (i = 0; i < len; i += 4) {
> + /* Read fifo must not be empty before all bytes are read */
> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +  val, !(val & GEN_PLD_R_EMPTY),
> +  1000, CMD_PKT_STATUS_TIMEOUT_US);
> + if (ret) {
> + dev_err(dsi->dev, "Read payload FIFO is empty\n");
> + return ret;
> + }
> +
> + val = dsi_read(dsi, DSI_GEN_PLD_DATA);
> + for (j = 0; j < 4 && j + i < len; j++)
> + buf[i + j] = val >> (8 * j);
> + }
> +
> + return ret;
> +}
> +
>  static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>const struct mipi_dsi_msg *msg)
>  {
>   struct dw_mipi_dsi *dsi = host_to_dsi(host);
>   struct mipi_dsi_packet packet;
> - int ret;
> -
> - if (msg->rx_buf || msg->rx_len) {
> - /* TODO dw drv improvements: implement read feature */
> - dev_warn(dsi->dev, "read operations not yet implemented\n");
> - return -EINVAL;
> - }
> + int ret, nb_bytes;
>  
>   ret = mipi_dsi_create_packet(, msg);
>   if (ret) {
> @@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct 
> mipi_dsi_host *host,
>   if (ret)
>   return ret;
>  
> - /*
> -  * TODO Only transmitted size is returned as actual driver does
> -  * not support dcs/generic reads. Please update return value when
> -  * delivering the read feature.
> -  */
> - return packet.size;
> + if (msg->rx_buf && msg->rx_len) {
> + ret = dw_mipi_dsi_read(dsi, msg);
> + if (ret)
> + return ret;
> + nb_bytes = msg->rx_len;
> + } else {
> + nb_bytes = packet.size;
> + }
> +
> + return nb_bytes;
>  }
>  
>  static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
> -- 
> 2.15.1
> 

Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Philippe CORNU]

Hi Andrzej,

And many thanks
Philippe :-)

On 02/05/2018 11:07 AM, Andrzej Hajda wrote:
> On 04.02.2018 22:31, Philippe Cornu wrote:
>> This patch adds the DCS/GENERIC DSI read feature.
>>
>> Signed-off-by: Philippe Cornu 
> 
> Reviewed-by: Andrzej Hajda 
> 
> If there will be no objections I will merge it at the end of the week.
> 
>   --
> Regards
> Andrzej
> 
>> ---
>> Extra notes:
>> DSI read tests have been performed with DCS & GENERIC, short & long
>> commands, on two different panels.
>> The maximum fifo size (32*32-bit = 128 bytes on stm32) has been
>> verified too.
>>
>>   drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 
>> +--
>>   1 file changed, 45 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
>> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> index e9422d05e897..65aeb3f78b48 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> @@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
>>  return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
>>   }
>>   
>> +static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
>> +const struct mipi_dsi_msg *msg)
>> +{
>> +int i, j, ret, len = msg->rx_len;
>> +u8 *buf = msg->rx_buf;
>> +u32 val;
>> +
>> +/* Wait end of the read operation */
>> +ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> + val, !(val & GEN_RD_CMD_BUSY),
>> + 1000, CMD_PKT_STATUS_TIMEOUT_US);
>> +if (ret) {
>> +dev_err(dsi->dev, "Timeout during read operation\n");
>> +return ret;
>> +}
>> +
>> +for (i = 0; i < len; i += 4) {
>> +/* Read fifo must not be empty before all bytes are read */
>> +ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> + val, !(val & GEN_PLD_R_EMPTY),
>> + 1000, CMD_PKT_STATUS_TIMEOUT_US);
>> +if (ret) {
>> +dev_err(dsi->dev, "Read payload FIFO is empty\n");
>> +return ret;
>> +}
>> +
>> +val = dsi_read(dsi, DSI_GEN_PLD_DATA);
>> +for (j = 0; j < 4 && j + i < len; j++)
>> +buf[i + j] = val >> (8 * j);
>> +}
>> +
>> +return ret;
>> +}
>> +
>>   static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>>   const struct mipi_dsi_msg *msg)
>>   {
>>  struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>  struct mipi_dsi_packet packet;
>> -int ret;
>> -
>> -if (msg->rx_buf || msg->rx_len) {
>> -/* TODO dw drv improvements: implement read feature */
>> -dev_warn(dsi->dev, "read operations not yet implemented\n");
>> -return -EINVAL;
>> -}
>> +int ret, nb_bytes;
>>   
>>  ret = mipi_dsi_create_packet(, msg);
>>  if (ret) {
>> @@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct 
>> mipi_dsi_host *host,
>>  if (ret)
>>  return ret;
>>   
>> -/*
>> - * TODO Only transmitted size is returned as actual driver does
>> - * not support dcs/generic reads. Please update return value when
>> - * delivering the read feature.
>> - */
>> -return packet.size;
>> +if (msg->rx_buf && msg->rx_len) {
>> +ret = dw_mipi_dsi_read(dsi, msg);
>> +if (ret)
>> +return ret;
>> +nb_bytes = msg->rx_len;
>> +} else {
>> +nb_bytes = packet.size;
>> +}
>> +
>> +return nb_bytes;
>>   }
>>   
>>   static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
> 
> 

Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Philippe CORNU]

Hi Andrzej,

And many thanks
Philippe :-)

On 02/05/2018 11:07 AM, Andrzej Hajda wrote:
> On 04.02.2018 22:31, Philippe Cornu wrote:
>> This patch adds the DCS/GENERIC DSI read feature.
>>
>> Signed-off-by: Philippe Cornu 
> 
> Reviewed-by: Andrzej Hajda 
> 
> If there will be no objections I will merge it at the end of the week.
> 
>   --
> Regards
> Andrzej
> 
>> ---
>> Extra notes:
>> DSI read tests have been performed with DCS & GENERIC, short & long
>> commands, on two different panels.
>> The maximum fifo size (32*32-bit = 128 bytes on stm32) has been
>> verified too.
>>
>>   drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 
>> +--
>>   1 file changed, 45 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
>> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> index e9422d05e897..65aeb3f78b48 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> @@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
>>  return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
>>   }
>>   
>> +static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
>> +const struct mipi_dsi_msg *msg)
>> +{
>> +int i, j, ret, len = msg->rx_len;
>> +u8 *buf = msg->rx_buf;
>> +u32 val;
>> +
>> +/* Wait end of the read operation */
>> +ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> + val, !(val & GEN_RD_CMD_BUSY),
>> + 1000, CMD_PKT_STATUS_TIMEOUT_US);
>> +if (ret) {
>> +dev_err(dsi->dev, "Timeout during read operation\n");
>> +return ret;
>> +}
>> +
>> +for (i = 0; i < len; i += 4) {
>> +/* Read fifo must not be empty before all bytes are read */
>> +ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> + val, !(val & GEN_PLD_R_EMPTY),
>> + 1000, CMD_PKT_STATUS_TIMEOUT_US);
>> +if (ret) {
>> +dev_err(dsi->dev, "Read payload FIFO is empty\n");
>> +return ret;
>> +}
>> +
>> +val = dsi_read(dsi, DSI_GEN_PLD_DATA);
>> +for (j = 0; j < 4 && j + i < len; j++)
>> +buf[i + j] = val >> (8 * j);
>> +}
>> +
>> +return ret;
>> +}
>> +
>>   static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>>   const struct mipi_dsi_msg *msg)
>>   {
>>  struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>  struct mipi_dsi_packet packet;
>> -int ret;
>> -
>> -if (msg->rx_buf || msg->rx_len) {
>> -/* TODO dw drv improvements: implement read feature */
>> -dev_warn(dsi->dev, "read operations not yet implemented\n");
>> -return -EINVAL;
>> -}
>> +int ret, nb_bytes;
>>   
>>  ret = mipi_dsi_create_packet(, msg);
>>  if (ret) {
>> @@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct 
>> mipi_dsi_host *host,
>>  if (ret)
>>  return ret;
>>   
>> -/*
>> - * TODO Only transmitted size is returned as actual driver does
>> - * not support dcs/generic reads. Please update return value when
>> - * delivering the read feature.
>> - */
>> -return packet.size;
>> +if (msg->rx_buf && msg->rx_len) {
>> +ret = dw_mipi_dsi_read(dsi, msg);
>> +if (ret)
>> +return ret;
>> +nb_bytes = msg->rx_len;
>> +} else {
>> +nb_bytes = packet.size;
>> +}
>> +
>> +return nb_bytes;
>>   }
>>   
>>   static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
> 
> 

Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Andrzej Hajda]

On 04.02.2018 22:31, Philippe Cornu wrote:
> This patch adds the DCS/GENERIC DSI read feature.
>
> Signed-off-by: Philippe Cornu 

Reviewed-by: Andrzej Hajda 

If there will be no objections I will merge it at the end of the week.

 --
Regards
Andrzej

> ---
> Extra notes:
> DSI read tests have been performed with DCS & GENERIC, short & long
> commands, on two different panels.
> The maximum fifo size (32*32-bit = 128 bytes on stm32) has been
> verified too.
>
>  drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 
> +--
>  1 file changed, 45 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index e9422d05e897..65aeb3f78b48 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
>   return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
>  }
>  
> +static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
> + const struct mipi_dsi_msg *msg)
> +{
> + int i, j, ret, len = msg->rx_len;
> + u8 *buf = msg->rx_buf;
> + u32 val;
> +
> + /* Wait end of the read operation */
> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +  val, !(val & GEN_RD_CMD_BUSY),
> +  1000, CMD_PKT_STATUS_TIMEOUT_US);
> + if (ret) {
> + dev_err(dsi->dev, "Timeout during read operation\n");
> + return ret;
> + }
> +
> + for (i = 0; i < len; i += 4) {
> + /* Read fifo must not be empty before all bytes are read */
> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +  val, !(val & GEN_PLD_R_EMPTY),
> +  1000, CMD_PKT_STATUS_TIMEOUT_US);
> + if (ret) {
> + dev_err(dsi->dev, "Read payload FIFO is empty\n");
> + return ret;
> + }
> +
> + val = dsi_read(dsi, DSI_GEN_PLD_DATA);
> + for (j = 0; j < 4 && j + i < len; j++)
> + buf[i + j] = val >> (8 * j);
> + }
> +
> + return ret;
> +}
> +
>  static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>const struct mipi_dsi_msg *msg)
>  {
>   struct dw_mipi_dsi *dsi = host_to_dsi(host);
>   struct mipi_dsi_packet packet;
> - int ret;
> -
> - if (msg->rx_buf || msg->rx_len) {
> - /* TODO dw drv improvements: implement read feature */
> - dev_warn(dsi->dev, "read operations not yet implemented\n");
> - return -EINVAL;
> - }
> + int ret, nb_bytes;
>  
>   ret = mipi_dsi_create_packet(, msg);
>   if (ret) {
> @@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct 
> mipi_dsi_host *host,
>   if (ret)
>   return ret;
>  
> - /*
> -  * TODO Only transmitted size is returned as actual driver does
> -  * not support dcs/generic reads. Please update return value when
> -  * delivering the read feature.
> -  */
> - return packet.size;
> + if (msg->rx_buf && msg->rx_len) {
> + ret = dw_mipi_dsi_read(dsi, msg);
> + if (ret)
> + return ret;
> + nb_bytes = msg->rx_len;
> + } else {
> + nb_bytes = packet.size;
> + }
> +
> + return nb_bytes;
>  }
>  
>  static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {

Re: [PATCH] drm/bridge/synopsys: dsi: Add read feature

[Andrzej Hajda]

On 04.02.2018 22:31, Philippe Cornu wrote:
> This patch adds the DCS/GENERIC DSI read feature.
>
> Signed-off-by: Philippe Cornu 

Reviewed-by: Andrzej Hajda 

If there will be no objections I will merge it at the end of the week.

 --
Regards
Andrzej

> ---
> Extra notes:
> DSI read tests have been performed with DCS & GENERIC, short & long
> commands, on two different panels.
> The maximum fifo size (32*32-bit = 128 bytes on stm32) has been
> verified too.
>
>  drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 
> +--
>  1 file changed, 45 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index e9422d05e897..65aeb3f78b48 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
>   return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
>  }
>  
> +static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
> + const struct mipi_dsi_msg *msg)
> +{
> + int i, j, ret, len = msg->rx_len;
> + u8 *buf = msg->rx_buf;
> + u32 val;
> +
> + /* Wait end of the read operation */
> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +  val, !(val & GEN_RD_CMD_BUSY),
> +  1000, CMD_PKT_STATUS_TIMEOUT_US);
> + if (ret) {
> + dev_err(dsi->dev, "Timeout during read operation\n");
> + return ret;
> + }
> +
> + for (i = 0; i < len; i += 4) {
> + /* Read fifo must not be empty before all bytes are read */
> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +  val, !(val & GEN_PLD_R_EMPTY),
> +  1000, CMD_PKT_STATUS_TIMEOUT_US);
> + if (ret) {
> + dev_err(dsi->dev, "Read payload FIFO is empty\n");
> + return ret;
> + }
> +
> + val = dsi_read(dsi, DSI_GEN_PLD_DATA);
> + for (j = 0; j < 4 && j + i < len; j++)
> + buf[i + j] = val >> (8 * j);
> + }
> +
> + return ret;
> +}
> +
>  static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>const struct mipi_dsi_msg *msg)
>  {
>   struct dw_mipi_dsi *dsi = host_to_dsi(host);
>   struct mipi_dsi_packet packet;
> - int ret;
> -
> - if (msg->rx_buf || msg->rx_len) {
> - /* TODO dw drv improvements: implement read feature */
> - dev_warn(dsi->dev, "read operations not yet implemented\n");
> - return -EINVAL;
> - }
> + int ret, nb_bytes;
>  
>   ret = mipi_dsi_create_packet(, msg);
>   if (ret) {
> @@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct 
> mipi_dsi_host *host,
>   if (ret)
>   return ret;
>  
> - /*
> -  * TODO Only transmitted size is returned as actual driver does
> -  * not support dcs/generic reads. Please update return value when
> -  * delivering the read feature.
> -  */
> - return packet.size;
> + if (msg->rx_buf && msg->rx_len) {
> + ret = dw_mipi_dsi_read(dsi, msg);
> + if (ret)
> + return ret;
> + nb_bytes = msg->rx_len;
> + } else {
> + nb_bytes = packet.size;
> + }
> +
> + return nb_bytes;
>  }
>  
>  static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {

[PATCH] drm/bridge/synopsys: dsi: Add read feature

[Philippe Cornu]

This patch adds the DCS/GENERIC DSI read feature.

Signed-off-by: Philippe Cornu 
---
Extra notes:
DSI read tests have been performed with DCS & GENERIC, short & long
commands, on two different panels.
The maximum fifo size (32*32-bit = 128 bytes on stm32) has been
verified too.

 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 +--
 1 file changed, 45 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index e9422d05e897..65aeb3f78b48 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
 }
 
+static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
+   const struct mipi_dsi_msg *msg)
+{
+   int i, j, ret, len = msg->rx_len;
+   u8 *buf = msg->rx_buf;
+   u32 val;
+
+   /* Wait end of the read operation */
+   ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+val, !(val & GEN_RD_CMD_BUSY),
+1000, CMD_PKT_STATUS_TIMEOUT_US);
+   if (ret) {
+   dev_err(dsi->dev, "Timeout during read operation\n");
+   return ret;
+   }
+
+   for (i = 0; i < len; i += 4) {
+   /* Read fifo must not be empty before all bytes are read */
+   ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+val, !(val & GEN_PLD_R_EMPTY),
+1000, CMD_PKT_STATUS_TIMEOUT_US);
+   if (ret) {
+   dev_err(dsi->dev, "Read payload FIFO is empty\n");
+   return ret;
+   }
+
+   val = dsi_read(dsi, DSI_GEN_PLD_DATA);
+   for (j = 0; j < 4 && j + i < len; j++)
+   buf[i + j] = val >> (8 * j);
+   }
+
+   return ret;
+}
+
 static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
 const struct mipi_dsi_msg *msg)
 {
struct dw_mipi_dsi *dsi = host_to_dsi(host);
struct mipi_dsi_packet packet;
-   int ret;
-
-   if (msg->rx_buf || msg->rx_len) {
-   /* TODO dw drv improvements: implement read feature */
-   dev_warn(dsi->dev, "read operations not yet implemented\n");
-   return -EINVAL;
-   }
+   int ret, nb_bytes;
 
ret = mipi_dsi_create_packet(, msg);
if (ret) {
@@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct 
mipi_dsi_host *host,
if (ret)
return ret;
 
-   /*
-* TODO Only transmitted size is returned as actual driver does
-* not support dcs/generic reads. Please update return value when
-* delivering the read feature.
-*/
-   return packet.size;
+   if (msg->rx_buf && msg->rx_len) {
+   ret = dw_mipi_dsi_read(dsi, msg);
+   if (ret)
+   return ret;
+   nb_bytes = msg->rx_len;
+   } else {
+   nb_bytes = packet.size;
+   }
+
+   return nb_bytes;
 }
 
 static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
-- 
2.15.1

[PATCH] drm/bridge/synopsys: dsi: Add read feature

[Philippe Cornu]

This patch adds the DCS/GENERIC DSI read feature.

Signed-off-by: Philippe Cornu 
---
Extra notes:
DSI read tests have been performed with DCS & GENERIC, short & long
commands, on two different panels.
The maximum fifo size (32*32-bit = 128 bytes on stm32) has been
verified too.

 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 +--
 1 file changed, 45 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index e9422d05e897..65aeb3f78b48 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
 }
 
+static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
+   const struct mipi_dsi_msg *msg)
+{
+   int i, j, ret, len = msg->rx_len;
+   u8 *buf = msg->rx_buf;
+   u32 val;
+
+   /* Wait end of the read operation */
+   ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+val, !(val & GEN_RD_CMD_BUSY),
+1000, CMD_PKT_STATUS_TIMEOUT_US);
+   if (ret) {
+   dev_err(dsi->dev, "Timeout during read operation\n");
+   return ret;
+   }
+
+   for (i = 0; i < len; i += 4) {
+   /* Read fifo must not be empty before all bytes are read */
+   ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+val, !(val & GEN_PLD_R_EMPTY),
+1000, CMD_PKT_STATUS_TIMEOUT_US);
+   if (ret) {
+   dev_err(dsi->dev, "Read payload FIFO is empty\n");
+   return ret;
+   }
+
+   val = dsi_read(dsi, DSI_GEN_PLD_DATA);
+   for (j = 0; j < 4 && j + i < len; j++)
+   buf[i + j] = val >> (8 * j);
+   }
+
+   return ret;
+}
+
 static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
 const struct mipi_dsi_msg *msg)
 {
struct dw_mipi_dsi *dsi = host_to_dsi(host);
struct mipi_dsi_packet packet;
-   int ret;
-
-   if (msg->rx_buf || msg->rx_len) {
-   /* TODO dw drv improvements: implement read feature */
-   dev_warn(dsi->dev, "read operations not yet implemented\n");
-   return -EINVAL;
-   }
+   int ret, nb_bytes;
 
ret = mipi_dsi_create_packet(, msg);
if (ret) {
@@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct 
mipi_dsi_host *host,
if (ret)
return ret;
 
-   /*
-* TODO Only transmitted size is returned as actual driver does
-* not support dcs/generic reads. Please update return value when
-* delivering the read feature.
-*/
-   return packet.size;
+   if (msg->rx_buf && msg->rx_len) {
+   ret = dw_mipi_dsi_read(dsi, msg);
+   if (ret)
+   return ret;
+   nb_bytes = msg->rx_len;
+   } else {
+   nb_bytes = packet.size;
+   }
+
+   return nb_bytes;
 }
 
 static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
-- 
2.15.1