* [PATCH] spi: s3c64xx: Use DMA mode from fifo size
[not found] <CGME20240327033501epcas2p2bbe21301da5584f7f3a073c51a363c00@epcas2p2.samsung.com>
@ 2024-03-27 3:30 ` Jaewon Kim
0 siblings, 0 replies; 14+ messages in thread
From: Jaewon Kim @ 2024-03-27 3:30 UTC (permalink / raw)
To: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar
Cc: linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel,
Jaewon Kim
The SPI data size is smaller than FIFO, it operates in PIO mode,
and if it is larger than FIFO mode, DMA mode is selected.
If the data size is the same as the FIFO size, it operates in PIO mode
and data is separated into two transfer. In order to prevent,
DMA mode must be used from the case of FIFO and data size.
Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
---
drivers/spi/spi-s3c64xx.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 9fcbe040cb2f..81ed5fddf83e 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
if (sdd->rx_dma.ch && sdd->tx_dma.ch)
- return xfer->len > sdd->fifo_depth;
+ return xfer->len >= sdd->fifo_depth;
return false;
}
@@ -826,11 +826,11 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
return status;
}
- if (!is_polling(sdd) && (xfer->len > fifo_len) &&
+ if (!is_polling(sdd) && xfer->len >= fifo_len &&
sdd->rx_dma.ch && sdd->tx_dma.ch) {
use_dma = 1;
- } else if (xfer->len >= fifo_len) {
+ } else if (xfer->len > fifo_len) {
tx_buf = xfer->tx_buf;
rx_buf = xfer->rx_buf;
origin_len = xfer->len;
--
2.43.2
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH] spi: s3c64xx: Use DMA mode from fifo size
@ 2024-03-27 3:30 ` Jaewon Kim
0 siblings, 0 replies; 14+ messages in thread
From: Jaewon Kim @ 2024-03-27 3:30 UTC (permalink / raw)
To: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar
Cc: linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel,
Jaewon Kim
The SPI data size is smaller than FIFO, it operates in PIO mode,
and if it is larger than FIFO mode, DMA mode is selected.
If the data size is the same as the FIFO size, it operates in PIO mode
and data is separated into two transfer. In order to prevent,
DMA mode must be used from the case of FIFO and data size.
Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
---
drivers/spi/spi-s3c64xx.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 9fcbe040cb2f..81ed5fddf83e 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
if (sdd->rx_dma.ch && sdd->tx_dma.ch)
- return xfer->len > sdd->fifo_depth;
+ return xfer->len >= sdd->fifo_depth;
return false;
}
@@ -826,11 +826,11 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
return status;
}
- if (!is_polling(sdd) && (xfer->len > fifo_len) &&
+ if (!is_polling(sdd) && xfer->len >= fifo_len &&
sdd->rx_dma.ch && sdd->tx_dma.ch) {
use_dma = 1;
- } else if (xfer->len >= fifo_len) {
+ } else if (xfer->len > fifo_len) {
tx_buf = xfer->tx_buf;
rx_buf = xfer->rx_buf;
origin_len = xfer->len;
--
2.43.2
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
2024-03-27 3:30 ` Jaewon Kim
@ 2024-03-28 17:58 ` Sam Protsenko
-1 siblings, 0 replies; 14+ messages in thread
From: Sam Protsenko @ 2024-03-28 17:58 UTC (permalink / raw)
To: Jaewon Kim
Cc: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
On Tue, Mar 26, 2024 at 10:35 PM Jaewon Kim <jaewon02.kim@samsung.com> wrote:
>
> The SPI data size is smaller than FIFO, it operates in PIO mode,
Spelling: "The" -> "If the"
> and if it is larger than FIFO mode, DMA mode is selected.
>
> If the data size is the same as the FIFO size, it operates in PIO mode
> and data is separated into two transfer. In order to prevent,
Nit: "transfer" -> "transfers", "prevent" -> "prevent it"
> DMA mode must be used from the case of FIFO and data size.
>
You probably mean this code (it occurs two times in the driver):
xfer->len = fifo_len - 1;
Can you please elaborate on why it's done this way? Why can't we just
do "xfer->len = fifo_len" and use the whole FIFO for the transfer
instead? I don't understand the necessity to split the transfer into
two chunks if its size is of FIFO length -- wouldn't it fit into FIFO
in that case? (I'm pretty sure this change is correct, just want to
understand how exactly it works).
> Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
Just wonder if that fixes some throughput regression, or something
worse (like failed transfers when the transfer size is the same as
FIFO size)?
> Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
> ---
> drivers/spi/spi-s3c64xx.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index 9fcbe040cb2f..81ed5fddf83e 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
> struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
>
> if (sdd->rx_dma.ch && sdd->tx_dma.ch)
> - return xfer->len > sdd->fifo_depth;
> + return xfer->len >= sdd->fifo_depth;
>
> return false;
> }
> @@ -826,11 +826,11 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
> return status;
> }
>
> - if (!is_polling(sdd) && (xfer->len > fifo_len) &&
> + if (!is_polling(sdd) && xfer->len >= fifo_len &&
> sdd->rx_dma.ch && sdd->tx_dma.ch) {
> use_dma = 1;
>
Would be nice to remove this empty line, while at it.
> - } else if (xfer->len >= fifo_len) {
> + } else if (xfer->len > fifo_len) {
Below in the same function I can see similar code:
if (target_len >= fifo_len)
xfer->len = fifo_len - 1;
Shouldn't that 'if' condition be fixed too? Or it's ok as it is? (Just
noticed it by searching, not sure myself, hence asking).
> tx_buf = xfer->tx_buf;
> rx_buf = xfer->rx_buf;
> origin_len = xfer->len;
> --
> 2.43.2
>
>
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
@ 2024-03-28 17:58 ` Sam Protsenko
0 siblings, 0 replies; 14+ messages in thread
From: Sam Protsenko @ 2024-03-28 17:58 UTC (permalink / raw)
To: Jaewon Kim
Cc: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
On Tue, Mar 26, 2024 at 10:35 PM Jaewon Kim <jaewon02.kim@samsung.com> wrote:
>
> The SPI data size is smaller than FIFO, it operates in PIO mode,
Spelling: "The" -> "If the"
> and if it is larger than FIFO mode, DMA mode is selected.
>
> If the data size is the same as the FIFO size, it operates in PIO mode
> and data is separated into two transfer. In order to prevent,
Nit: "transfer" -> "transfers", "prevent" -> "prevent it"
> DMA mode must be used from the case of FIFO and data size.
>
You probably mean this code (it occurs two times in the driver):
xfer->len = fifo_len - 1;
Can you please elaborate on why it's done this way? Why can't we just
do "xfer->len = fifo_len" and use the whole FIFO for the transfer
instead? I don't understand the necessity to split the transfer into
two chunks if its size is of FIFO length -- wouldn't it fit into FIFO
in that case? (I'm pretty sure this change is correct, just want to
understand how exactly it works).
> Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
Just wonder if that fixes some throughput regression, or something
worse (like failed transfers when the transfer size is the same as
FIFO size)?
> Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
> ---
> drivers/spi/spi-s3c64xx.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index 9fcbe040cb2f..81ed5fddf83e 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
> struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
>
> if (sdd->rx_dma.ch && sdd->tx_dma.ch)
> - return xfer->len > sdd->fifo_depth;
> + return xfer->len >= sdd->fifo_depth;
>
> return false;
> }
> @@ -826,11 +826,11 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
> return status;
> }
>
> - if (!is_polling(sdd) && (xfer->len > fifo_len) &&
> + if (!is_polling(sdd) && xfer->len >= fifo_len &&
> sdd->rx_dma.ch && sdd->tx_dma.ch) {
> use_dma = 1;
>
Would be nice to remove this empty line, while at it.
> - } else if (xfer->len >= fifo_len) {
> + } else if (xfer->len > fifo_len) {
Below in the same function I can see similar code:
if (target_len >= fifo_len)
xfer->len = fifo_len - 1;
Shouldn't that 'if' condition be fixed too? Or it's ok as it is? (Just
noticed it by searching, not sure myself, hence asking).
> tx_buf = xfer->tx_buf;
> rx_buf = xfer->rx_buf;
> origin_len = xfer->len;
> --
> 2.43.2
>
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
2024-03-28 17:58 ` Sam Protsenko
@ 2024-03-29 5:53 ` Jaewon Kim
-1 siblings, 0 replies; 14+ messages in thread
From: Jaewon Kim @ 2024-03-29 5:53 UTC (permalink / raw)
To: Sam Protsenko
Cc: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
Hi Sam,
Thanks for your review.
On 3/29/24 02:58, Sam Protsenko wrote:
> On Tue, Mar 26, 2024 at 10:35 PM Jaewon Kim<jaewon02.kim@samsung.com> wrote:
>> The SPI data size is smaller than FIFO, it operates in PIO mode,
> Spelling: "The" -> "If the"
Thanks, I will fix it v2.
>> and if it is larger than FIFO mode, DMA mode is selected.
>>
>> If the data size is the same as the FIFO size, it operates in PIO mode
>> and data is separated into two transfer. In order to prevent,
> Nit: "transfer" -> "transfers", "prevent" -> "prevent it"
Thanks, I will fix it v2.
>> DMA mode must be used from the case of FIFO and data size.
>>
> You probably mean this code (it occurs two times in the driver):
>
> xfer->len = fifo_len - 1;
>
> Can you please elaborate on why it's done this way? Why can't we just
> do "xfer->len = fifo_len" and use the whole FIFO for the transfer
> instead? I don't understand the necessity to split the transfer into
> two chunks if its size is of FIFO length -- wouldn't it fit into FIFO
> in that case? (I'm pretty sure this change is correct, just want to
> understand how exactly it works).
In IRQ mode(S3C64XX_SPI_MODE_RX_RDY_LVL enable), TxOverrun/RxUnderrun
irq occurs when FIFO is full.
To avoid FIFO full, it is transmitted in a smaller size than
fifo_len.(fifo-len - 1)
However, in case of "fifo_len == data size" "fifo_len - 1" byte + "1"
byte were transmitted separately.
This problem can be solved by starting DMA transmission start size from
fifo_len.
>> Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
> Just wonder if that fixes some throughput regression, or something
> worse (like failed transfers when the transfer size is the same as
> FIFO size)?
It is not a critical issue, but When I look at the actual waveform, it
seems strange that only the last 1-byte is transmitted separately.
I thought it was "Fixes", but if not, I will remove it.
>> Signed-off-by: Jaewon Kim<jaewon02.kim@samsung.com>
>> ---
>> drivers/spi/spi-s3c64xx.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
>> index 9fcbe040cb2f..81ed5fddf83e 100644
>> --- a/drivers/spi/spi-s3c64xx.c
>> +++ b/drivers/spi/spi-s3c64xx.c
>> @@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
>> struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
>>
>> if (sdd->rx_dma.ch && sdd->tx_dma.ch)
>> - return xfer->len > sdd->fifo_depth;
>> + return xfer->len >= sdd->fifo_depth;
>>
>> return false;
>> }
>> @@ -826,11 +826,11 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
>> return status;
>> }
>>
>> - if (!is_polling(sdd) && (xfer->len > fifo_len) &&
>> + if (!is_polling(sdd) && xfer->len >= fifo_len &&
>> sdd->rx_dma.ch && sdd->tx_dma.ch) {
>> use_dma = 1;
>>
> Would be nice to remove this empty line, while at it.
Good, I will remove it also.
>> - } else if (xfer->len >= fifo_len) {
>> + } else if (xfer->len > fifo_len) {
> Below in the same function I can see similar code:
>
> if (target_len >= fifo_len)
> xfer->len = fifo_len - 1;
>
> Shouldn't that 'if' condition be fixed too? Or it's ok as it is? (Just
> noticed it by searching, not sure myself, hence asking).
You are correct. This 'if' condition should not have been modified.
>> tx_buf = xfer->tx_buf;
>> rx_buf = xfer->rx_buf;
>> origin_len = xfer->len;
>> --
>> 2.43.2
>>
>>
Thanks
Jaewon Kim
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
@ 2024-03-29 5:53 ` Jaewon Kim
0 siblings, 0 replies; 14+ messages in thread
From: Jaewon Kim @ 2024-03-29 5:53 UTC (permalink / raw)
To: Sam Protsenko
Cc: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
Hi Sam,
Thanks for your review.
On 3/29/24 02:58, Sam Protsenko wrote:
> On Tue, Mar 26, 2024 at 10:35 PM Jaewon Kim<jaewon02.kim@samsung.com> wrote:
>> The SPI data size is smaller than FIFO, it operates in PIO mode,
> Spelling: "The" -> "If the"
Thanks, I will fix it v2.
>> and if it is larger than FIFO mode, DMA mode is selected.
>>
>> If the data size is the same as the FIFO size, it operates in PIO mode
>> and data is separated into two transfer. In order to prevent,
> Nit: "transfer" -> "transfers", "prevent" -> "prevent it"
Thanks, I will fix it v2.
>> DMA mode must be used from the case of FIFO and data size.
>>
> You probably mean this code (it occurs two times in the driver):
>
> xfer->len = fifo_len - 1;
>
> Can you please elaborate on why it's done this way? Why can't we just
> do "xfer->len = fifo_len" and use the whole FIFO for the transfer
> instead? I don't understand the necessity to split the transfer into
> two chunks if its size is of FIFO length -- wouldn't it fit into FIFO
> in that case? (I'm pretty sure this change is correct, just want to
> understand how exactly it works).
In IRQ mode(S3C64XX_SPI_MODE_RX_RDY_LVL enable), TxOverrun/RxUnderrun
irq occurs when FIFO is full.
To avoid FIFO full, it is transmitted in a smaller size than
fifo_len.(fifo-len - 1)
However, in case of "fifo_len == data size" "fifo_len - 1" byte + "1"
byte were transmitted separately.
This problem can be solved by starting DMA transmission start size from
fifo_len.
>> Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
> Just wonder if that fixes some throughput regression, or something
> worse (like failed transfers when the transfer size is the same as
> FIFO size)?
It is not a critical issue, but When I look at the actual waveform, it
seems strange that only the last 1-byte is transmitted separately.
I thought it was "Fixes", but if not, I will remove it.
>> Signed-off-by: Jaewon Kim<jaewon02.kim@samsung.com>
>> ---
>> drivers/spi/spi-s3c64xx.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
>> index 9fcbe040cb2f..81ed5fddf83e 100644
>> --- a/drivers/spi/spi-s3c64xx.c
>> +++ b/drivers/spi/spi-s3c64xx.c
>> @@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
>> struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
>>
>> if (sdd->rx_dma.ch && sdd->tx_dma.ch)
>> - return xfer->len > sdd->fifo_depth;
>> + return xfer->len >= sdd->fifo_depth;
>>
>> return false;
>> }
>> @@ -826,11 +826,11 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
>> return status;
>> }
>>
>> - if (!is_polling(sdd) && (xfer->len > fifo_len) &&
>> + if (!is_polling(sdd) && xfer->len >= fifo_len &&
>> sdd->rx_dma.ch && sdd->tx_dma.ch) {
>> use_dma = 1;
>>
> Would be nice to remove this empty line, while at it.
Good, I will remove it also.
>> - } else if (xfer->len >= fifo_len) {
>> + } else if (xfer->len > fifo_len) {
> Below in the same function I can see similar code:
>
> if (target_len >= fifo_len)
> xfer->len = fifo_len - 1;
>
> Shouldn't that 'if' condition be fixed too? Or it's ok as it is? (Just
> noticed it by searching, not sure myself, hence asking).
You are correct. This 'if' condition should not have been modified.
>> tx_buf = xfer->tx_buf;
>> rx_buf = xfer->rx_buf;
>> origin_len = xfer->len;
>> --
>> 2.43.2
>>
>>
Thanks
Jaewon Kim
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
2024-03-29 5:53 ` Jaewon Kim
@ 2024-03-29 6:01 ` Sam Protsenko
-1 siblings, 0 replies; 14+ messages in thread
From: Sam Protsenko @ 2024-03-29 6:01 UTC (permalink / raw)
To: Jaewon Kim
Cc: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
On Fri, Mar 29, 2024 at 12:53 AM Jaewon Kim <jaewon02.kim@samsung.com> wrote:
>
> Hi Sam,
>
> Thanks for your review.
>
>
> On 3/29/24 02:58, Sam Protsenko wrote:
> > On Tue, Mar 26, 2024 at 10:35 PM Jaewon Kim<jaewon02.kim@samsung.com> wrote:
> >> The SPI data size is smaller than FIFO, it operates in PIO mode,
> > Spelling: "The" -> "If the"
>
> Thanks, I will fix it v2.
>
> >> and if it is larger than FIFO mode, DMA mode is selected.
> >>
> >> If the data size is the same as the FIFO size, it operates in PIO mode
> >> and data is separated into two transfer. In order to prevent,
> > Nit: "transfer" -> "transfers", "prevent" -> "prevent it"
>
> Thanks, I will fix it v2.
>
> >> DMA mode must be used from the case of FIFO and data size.
> >>
> > You probably mean this code (it occurs two times in the driver):
> >
> > xfer->len = fifo_len - 1;
> >
> > Can you please elaborate on why it's done this way? Why can't we just
> > do "xfer->len = fifo_len" and use the whole FIFO for the transfer
> > instead? I don't understand the necessity to split the transfer into
> > two chunks if its size is of FIFO length -- wouldn't it fit into FIFO
> > in that case? (I'm pretty sure this change is correct, just want to
> > understand how exactly it works).
>
> In IRQ mode(S3C64XX_SPI_MODE_RX_RDY_LVL enable), TxOverrun/RxUnderrun
> irq occurs when FIFO is full.
>
> To avoid FIFO full, it is transmitted in a smaller size than
> fifo_len.(fifo-len - 1)
>
> However, in case of "fifo_len == data size" "fifo_len - 1" byte + "1"
> byte were transmitted separately.
>
> This problem can be solved by starting DMA transmission start size from
> fifo_len.
>
Thanks for the explanation! Please feel free to add:
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
> >> Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
> > Just wonder if that fixes some throughput regression, or something
> > worse (like failed transfers when the transfer size is the same as
> > FIFO size)?
>
> It is not a critical issue, but When I look at the actual waveform, it
> seems strange that only the last 1-byte is transmitted separately.
>
> I thought it was "Fixes", but if not, I will remove it.
>
No no, I was just curious. "Fixes" is fine with me.
> >> Signed-off-by: Jaewon Kim<jaewon02.kim@samsung.com>
> >> ---
> >> drivers/spi/spi-s3c64xx.c | 6 +++---
> >> 1 file changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> >> index 9fcbe040cb2f..81ed5fddf83e 100644
> >> --- a/drivers/spi/spi-s3c64xx.c
> >> +++ b/drivers/spi/spi-s3c64xx.c
> >> @@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
> >> struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
> >>
> >> if (sdd->rx_dma.ch && sdd->tx_dma.ch)
> >> - return xfer->len > sdd->fifo_depth;
> >> + return xfer->len >= sdd->fifo_depth;
> >>
> >> return false;
> >> }
> >> @@ -826,11 +826,11 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
> >> return status;
> >> }
> >>
> >> - if (!is_polling(sdd) && (xfer->len > fifo_len) &&
> >> + if (!is_polling(sdd) && xfer->len >= fifo_len &&
> >> sdd->rx_dma.ch && sdd->tx_dma.ch) {
> >> use_dma = 1;
> >>
> > Would be nice to remove this empty line, while at it.
> Good, I will remove it also.
> >> - } else if (xfer->len >= fifo_len) {
> >> + } else if (xfer->len > fifo_len) {
> > Below in the same function I can see similar code:
> >
> > if (target_len >= fifo_len)
> > xfer->len = fifo_len - 1;
> >
> > Shouldn't that 'if' condition be fixed too? Or it's ok as it is? (Just
> > noticed it by searching, not sure myself, hence asking).
>
> You are correct. This 'if' condition should not have been modified.
>
> >> tx_buf = xfer->tx_buf;
> >> rx_buf = xfer->rx_buf;
> >> origin_len = xfer->len;
> >> --
> >> 2.43.2
> >>
> >>
>
> Thanks
>
> Jaewon Kim
>
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
@ 2024-03-29 6:01 ` Sam Protsenko
0 siblings, 0 replies; 14+ messages in thread
From: Sam Protsenko @ 2024-03-29 6:01 UTC (permalink / raw)
To: Jaewon Kim
Cc: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
On Fri, Mar 29, 2024 at 12:53 AM Jaewon Kim <jaewon02.kim@samsung.com> wrote:
>
> Hi Sam,
>
> Thanks for your review.
>
>
> On 3/29/24 02:58, Sam Protsenko wrote:
> > On Tue, Mar 26, 2024 at 10:35 PM Jaewon Kim<jaewon02.kim@samsung.com> wrote:
> >> The SPI data size is smaller than FIFO, it operates in PIO mode,
> > Spelling: "The" -> "If the"
>
> Thanks, I will fix it v2.
>
> >> and if it is larger than FIFO mode, DMA mode is selected.
> >>
> >> If the data size is the same as the FIFO size, it operates in PIO mode
> >> and data is separated into two transfer. In order to prevent,
> > Nit: "transfer" -> "transfers", "prevent" -> "prevent it"
>
> Thanks, I will fix it v2.
>
> >> DMA mode must be used from the case of FIFO and data size.
> >>
> > You probably mean this code (it occurs two times in the driver):
> >
> > xfer->len = fifo_len - 1;
> >
> > Can you please elaborate on why it's done this way? Why can't we just
> > do "xfer->len = fifo_len" and use the whole FIFO for the transfer
> > instead? I don't understand the necessity to split the transfer into
> > two chunks if its size is of FIFO length -- wouldn't it fit into FIFO
> > in that case? (I'm pretty sure this change is correct, just want to
> > understand how exactly it works).
>
> In IRQ mode(S3C64XX_SPI_MODE_RX_RDY_LVL enable), TxOverrun/RxUnderrun
> irq occurs when FIFO is full.
>
> To avoid FIFO full, it is transmitted in a smaller size than
> fifo_len.(fifo-len - 1)
>
> However, in case of "fifo_len == data size" "fifo_len - 1" byte + "1"
> byte were transmitted separately.
>
> This problem can be solved by starting DMA transmission start size from
> fifo_len.
>
Thanks for the explanation! Please feel free to add:
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
> >> Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
> > Just wonder if that fixes some throughput regression, or something
> > worse (like failed transfers when the transfer size is the same as
> > FIFO size)?
>
> It is not a critical issue, but When I look at the actual waveform, it
> seems strange that only the last 1-byte is transmitted separately.
>
> I thought it was "Fixes", but if not, I will remove it.
>
No no, I was just curious. "Fixes" is fine with me.
> >> Signed-off-by: Jaewon Kim<jaewon02.kim@samsung.com>
> >> ---
> >> drivers/spi/spi-s3c64xx.c | 6 +++---
> >> 1 file changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> >> index 9fcbe040cb2f..81ed5fddf83e 100644
> >> --- a/drivers/spi/spi-s3c64xx.c
> >> +++ b/drivers/spi/spi-s3c64xx.c
> >> @@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
> >> struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
> >>
> >> if (sdd->rx_dma.ch && sdd->tx_dma.ch)
> >> - return xfer->len > sdd->fifo_depth;
> >> + return xfer->len >= sdd->fifo_depth;
> >>
> >> return false;
> >> }
> >> @@ -826,11 +826,11 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
> >> return status;
> >> }
> >>
> >> - if (!is_polling(sdd) && (xfer->len > fifo_len) &&
> >> + if (!is_polling(sdd) && xfer->len >= fifo_len &&
> >> sdd->rx_dma.ch && sdd->tx_dma.ch) {
> >> use_dma = 1;
> >>
> > Would be nice to remove this empty line, while at it.
> Good, I will remove it also.
> >> - } else if (xfer->len >= fifo_len) {
> >> + } else if (xfer->len > fifo_len) {
> > Below in the same function I can see similar code:
> >
> > if (target_len >= fifo_len)
> > xfer->len = fifo_len - 1;
> >
> > Shouldn't that 'if' condition be fixed too? Or it's ok as it is? (Just
> > noticed it by searching, not sure myself, hence asking).
>
> You are correct. This 'if' condition should not have been modified.
>
> >> tx_buf = xfer->tx_buf;
> >> rx_buf = xfer->rx_buf;
> >> origin_len = xfer->len;
> >> --
> >> 2.43.2
> >>
> >>
>
> Thanks
>
> Jaewon Kim
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH] spi: s3c64xx: Use DMA mode from fifo size
[not found] <CGME20240329090313epcas2p2cf95d22e44b6b1c120021622da68aeb8@epcas2p2.samsung.com>
@ 2024-03-29 8:58 ` Jaewon Kim
0 siblings, 0 replies; 14+ messages in thread
From: Jaewon Kim @ 2024-03-29 8:58 UTC (permalink / raw)
To: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
Sam Protsenko
Cc: linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel,
Jaewon Kim
If the SPI data size is smaller than FIFO, it operates in PIO mode,
and if it is larger than FIFO size, it oerates in DMA mode.
If the SPI data size is equal to fifo, it operates in PIO mode and it is
separated to 2 transfers. To prevent it, it must operate in DMA mode
from the case where the data size and the fifo size are the same.
Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
---
drivers/spi/spi-s3c64xx.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 9fcbe040cb2f..f726d8670428 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
if (sdd->rx_dma.ch && sdd->tx_dma.ch)
- return xfer->len > sdd->fifo_depth;
+ return xfer->len >= sdd->fifo_depth;
return false;
}
@@ -826,10 +826,9 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
return status;
}
- if (!is_polling(sdd) && (xfer->len > fifo_len) &&
+ if (!is_polling(sdd) && xfer->len >= fifo_len &&
sdd->rx_dma.ch && sdd->tx_dma.ch) {
use_dma = 1;
-
} else if (xfer->len >= fifo_len) {
tx_buf = xfer->tx_buf;
rx_buf = xfer->rx_buf;
--
2.43.2
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH] spi: s3c64xx: Use DMA mode from fifo size
@ 2024-03-29 8:58 ` Jaewon Kim
0 siblings, 0 replies; 14+ messages in thread
From: Jaewon Kim @ 2024-03-29 8:58 UTC (permalink / raw)
To: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
Sam Protsenko
Cc: linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel,
Jaewon Kim
If the SPI data size is smaller than FIFO, it operates in PIO mode,
and if it is larger than FIFO size, it oerates in DMA mode.
If the SPI data size is equal to fifo, it operates in PIO mode and it is
separated to 2 transfers. To prevent it, it must operate in DMA mode
from the case where the data size and the fifo size are the same.
Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
---
drivers/spi/spi-s3c64xx.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 9fcbe040cb2f..f726d8670428 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
if (sdd->rx_dma.ch && sdd->tx_dma.ch)
- return xfer->len > sdd->fifo_depth;
+ return xfer->len >= sdd->fifo_depth;
return false;
}
@@ -826,10 +826,9 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
return status;
}
- if (!is_polling(sdd) && (xfer->len > fifo_len) &&
+ if (!is_polling(sdd) && xfer->len >= fifo_len &&
sdd->rx_dma.ch && sdd->tx_dma.ch) {
use_dma = 1;
-
} else if (xfer->len >= fifo_len) {
tx_buf = xfer->tx_buf;
rx_buf = xfer->rx_buf;
--
2.43.2
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
2024-03-29 8:58 ` Jaewon Kim
@ 2024-03-29 9:09 ` Jaewon Kim
-1 siblings, 0 replies; 14+ messages in thread
From: Jaewon Kim @ 2024-03-29 9:09 UTC (permalink / raw)
To: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
Sam Protsenko
Cc: linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
On 3/29/24 17:58, Jaewon Kim wrote:
> If the SPI data size is smaller than FIFO, it operates in PIO mode,
> and if it is larger than FIFO size, it oerates in DMA mode.
>
> If the SPI data size is equal to fifo, it operates in PIO mode and it is
> separated to 2 transfers. To prevent it, it must operate in DMA mode
> from the case where the data size and the fifo size are the same.
>
> Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
> Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
> Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
> drivers/spi/spi-s3c64xx.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index 9fcbe040cb2f..f726d8670428 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
> struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
>
> if (sdd->rx_dma.ch && sdd->tx_dma.ch)
> - return xfer->len > sdd->fifo_depth;
> + return xfer->len >= sdd->fifo_depth;
>
> return false;
> }
> @@ -826,10 +826,9 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
> return status;
> }
>
> - if (!is_polling(sdd) && (xfer->len > fifo_len) &&
> + if (!is_polling(sdd) && xfer->len >= fifo_len &&
> sdd->rx_dma.ch && sdd->tx_dma.ch) {
> use_dma = 1;
> -
> } else if (xfer->len >= fifo_len) {
> tx_buf = xfer->tx_buf;
> rx_buf = xfer->rx_buf;
Sorry, I didn't add v2 by mistake.
This is v1 mail thread.
-
https://lore.kernel.org/linux-arm-kernel/CAPLW+4k4qh4ZYBufZoGbUZN0yxSE2X8bOdkEQVw1Zg9YUVpbug@mail.gmail.com/T/
Thanks
Jaewon Kim
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
@ 2024-03-29 9:09 ` Jaewon Kim
0 siblings, 0 replies; 14+ messages in thread
From: Jaewon Kim @ 2024-03-29 9:09 UTC (permalink / raw)
To: Andi Shyti, Mark Brown, Krzysztof Kozlowski, Alim Akhtar,
Sam Protsenko
Cc: linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
On 3/29/24 17:58, Jaewon Kim wrote:
> If the SPI data size is smaller than FIFO, it operates in PIO mode,
> and if it is larger than FIFO size, it oerates in DMA mode.
>
> If the SPI data size is equal to fifo, it operates in PIO mode and it is
> separated to 2 transfers. To prevent it, it must operate in DMA mode
> from the case where the data size and the fifo size are the same.
>
> Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
> Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
> Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
> drivers/spi/spi-s3c64xx.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index 9fcbe040cb2f..f726d8670428 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
> struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
>
> if (sdd->rx_dma.ch && sdd->tx_dma.ch)
> - return xfer->len > sdd->fifo_depth;
> + return xfer->len >= sdd->fifo_depth;
>
> return false;
> }
> @@ -826,10 +826,9 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
> return status;
> }
>
> - if (!is_polling(sdd) && (xfer->len > fifo_len) &&
> + if (!is_polling(sdd) && xfer->len >= fifo_len &&
> sdd->rx_dma.ch && sdd->tx_dma.ch) {
> use_dma = 1;
> -
> } else if (xfer->len >= fifo_len) {
> tx_buf = xfer->tx_buf;
> rx_buf = xfer->rx_buf;
Sorry, I didn't add v2 by mistake.
This is v1 mail thread.
-
https://lore.kernel.org/linux-arm-kernel/CAPLW+4k4qh4ZYBufZoGbUZN0yxSE2X8bOdkEQVw1Zg9YUVpbug@mail.gmail.com/T/
Thanks
Jaewon Kim
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
2024-03-29 8:58 ` Jaewon Kim
@ 2024-03-29 17:35 ` Mark Brown
-1 siblings, 0 replies; 14+ messages in thread
From: Mark Brown @ 2024-03-29 17:35 UTC (permalink / raw)
To: Andi Shyti, Krzysztof Kozlowski, Alim Akhtar, Sam Protsenko,
Jaewon Kim
Cc: linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
On Fri, 29 Mar 2024 17:58:40 +0900, Jaewon Kim wrote:
> If the SPI data size is smaller than FIFO, it operates in PIO mode,
> and if it is larger than FIFO size, it oerates in DMA mode.
>
> If the SPI data size is equal to fifo, it operates in PIO mode and it is
> separated to 2 transfers. To prevent it, it must operate in DMA mode
> from the case where the data size and the fifo size are the same.
>
> [...]
Applied to
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next
Thanks!
[1/1] spi: s3c64xx: Use DMA mode from fifo size
commit: a3d3eab627bbbb0cb175910cf8d0f7022628a642
All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying
to this mail.
Thanks,
Mark
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] spi: s3c64xx: Use DMA mode from fifo size
@ 2024-03-29 17:35 ` Mark Brown
0 siblings, 0 replies; 14+ messages in thread
From: Mark Brown @ 2024-03-29 17:35 UTC (permalink / raw)
To: Andi Shyti, Krzysztof Kozlowski, Alim Akhtar, Sam Protsenko,
Jaewon Kim
Cc: linux-spi, linux-samsung-soc, linux-arm-kernel, linux-kernel
On Fri, 29 Mar 2024 17:58:40 +0900, Jaewon Kim wrote:
> If the SPI data size is smaller than FIFO, it operates in PIO mode,
> and if it is larger than FIFO size, it oerates in DMA mode.
>
> If the SPI data size is equal to fifo, it operates in PIO mode and it is
> separated to 2 transfers. To prevent it, it must operate in DMA mode
> from the case where the data size and the fifo size are the same.
>
> [...]
Applied to
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next
Thanks!
[1/1] spi: s3c64xx: Use DMA mode from fifo size
commit: a3d3eab627bbbb0cb175910cf8d0f7022628a642
All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying
to this mail.
Thanks,
Mark
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2024-03-29 17:35 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
[not found] <CGME20240329090313epcas2p2cf95d22e44b6b1c120021622da68aeb8@epcas2p2.samsung.com>
2024-03-29 8:58 ` [PATCH] spi: s3c64xx: Use DMA mode from fifo size Jaewon Kim
2024-03-29 8:58 ` Jaewon Kim
2024-03-29 9:09 ` Jaewon Kim
2024-03-29 9:09 ` Jaewon Kim
2024-03-29 17:35 ` Mark Brown
2024-03-29 17:35 ` Mark Brown
[not found] <CGME20240327033501epcas2p2bbe21301da5584f7f3a073c51a363c00@epcas2p2.samsung.com>
2024-03-27 3:30 ` Jaewon Kim
2024-03-27 3:30 ` Jaewon Kim
2024-03-28 17:58 ` Sam Protsenko
2024-03-28 17:58 ` Sam Protsenko
2024-03-29 5:53 ` Jaewon Kim
2024-03-29 5:53 ` Jaewon Kim
2024-03-29 6:01 ` Sam Protsenko
2024-03-29 6:01 ` Sam Protsenko
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