[PATCH v2] spi: omap2-mcspi: disable other channels CHCONF_FORCE in prepare_message

[PATCH v2] spi: omap2-mcspi: disable other channels CHCONF_FORCE in prepare_message

[Neil Armstrong]

Since the "Switch driver to use transfer_one" change, the cs_change
behavior has changed and a channel chip select can still be
asserted when changing channel from a previous last transfer in a
message having the cs_change attribute.

Since there is no sense having multiple chip select being asserted at the
same time, disable all the remaining forced chip selects in a the
prepare_message called right before a spi_transfer_one_message call.
It ignores the current channel configuration in order to keep the
possibility to leave the chip select asserted between messages.

It fixes this bug on a DM8168 SoC ES2.1 Soc and an OMAP4 ES2.1 SoC.
It was hanging all the other channels transfers when a CHCONF_FORCE
is present on the wrong channel.

Fixes: b28cb9414db9 ("spi: omap2-mcspi: Switch driver to use transfer_one")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/spi/spi-omap2-mcspi.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

Test code can be found on :
http://pastebin.com/0SrqbGP7

Before patch :
# ./test_spi
cs_change_command() start
spidev1.3 ioctl success
no_dma_command() start
[   59.790069] spidev spi1.1: TXS timed out
spidev1.1 ioctl success
cs_change_command() start
[   60.798736] spidev spi1.3: RXS timed out
spidev1.3 ioctl success
no_dma_command() start
[   61.802032] spidev spi1.1: TXS timed out
spidev1.1 ioctl success
cs_change_command() start
[   62.807525] spidev spi1.3: RXS timed out
spidev1.3 ioctl success
no_dma_command() start
[   63.812042] spidev spi1.1: TXS timed out
spidev1.1 ioctl success
...

After Patch :
# ./test_spi
cs_change_command() start
spidev1.3 ioctl success
no_dma_command() start
spidev1.1 ioctl success
cs_change_command() start
spidev1.3 ioctl success
no_dma_command() start
spidev1.1 ioctl success
cs_change_command() start
spidev1.3 ioctl success
...

v2: uses msg to leave asserted chip select for the current channel

This is a patch RFC following the bug report :
'McSPI hangs with cs_change after "Switch driver to use transfer_one" change'
http://permalink.gmane.org/gmane.linux.kernel/2056841

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 3d09e0b..1f8903d 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -1217,6 +1217,33 @@ out:
 	return status;
 }

+static int omap2_mcspi_prepare_message(struct spi_master *master,
+				       struct spi_message *msg)
+{
+	struct omap2_mcspi	*mcspi = spi_master_get_devdata(master);
+	struct omap2_mcspi_regs	*ctx = &mcspi->ctx;
+	struct omap2_mcspi_cs	*cs;
+
+	/* Only a single channel can have the FORCE bit enabled
+	 * in its chconf0 register.
+	 * Scan all channels and disable them except the current one.
+	 * A FORCE can remain from a last transfer having cs_change enabled
+	 */
+	list_for_each_entry(cs, &ctx->cs, node) {
+		if (msg->spi->controller_state == cs)
+			continue;
+
+		if ((cs->chconf0 & OMAP2_MCSPI_CHCONF_FORCE)) {
+			cs->chconf0 &= ~OMAP2_MCSPI_CHCONF_FORCE;
+			writel_relaxed(cs->chconf0,
+					cs->base + OMAP2_MCSPI_CHCONF0);
+			readl_relaxed(cs->base + OMAP2_MCSPI_CHCONF0);
+		}
+	}
+
+	return 0;
+}
+
 static int omap2_mcspi_transfer_one(struct spi_master *master,
 		struct spi_device *spi, struct spi_transfer *t)
 {
@@ -1344,6 +1371,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
 	master->setup = omap2_mcspi_setup;
 	master->auto_runtime_pm = true;
+	master->prepare_message = omap2_mcspi_prepare_message;
 	master->transfer_one = omap2_mcspi_transfer_one;
 	master->set_cs = omap2_mcspi_set_cs;
 	master->cleanup = omap2_mcspi_cleanup;
-- 
1.9.1

Re: [PATCH v2] spi: omap2-mcspi: disable other channels CHCONF_FORCE in prepare_message

[Michael Welling]

On Fri, Oct 09, 2015 at 03:47:41PM +0200, Neil Armstrong wrote:
> Since the "Switch driver to use transfer_one" change, the cs_change
> behavior has changed and a channel chip select can still be
> asserted when changing channel from a previous last transfer in a
> message having the cs_change attribute.
> 
> Since there is no sense having multiple chip select being asserted at the
> same time, disable all the remaining forced chip selects in a the
> prepare_message called right before a spi_transfer_one_message call.
> It ignores the current channel configuration in order to keep the
> possibility to leave the chip select asserted between messages.
> 
> It fixes this bug on a DM8168 SoC ES2.1 Soc and an OMAP4 ES2.1 SoC.
> It was hanging all the other channels transfers when a CHCONF_FORCE
> is present on the wrong channel.
> 
> Fixes: b28cb9414db9 ("spi: omap2-mcspi: Switch driver to use transfer_one")
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
>  drivers/spi/spi-omap2-mcspi.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> Test code can be found on :
> http://pastebin.com/0SrqbGP7
> 
> Before patch :
> # ./test_spi
> cs_change_command() start
> spidev1.3 ioctl success
> no_dma_command() start
> [   59.790069] spidev spi1.1: TXS timed out
> spidev1.1 ioctl success
> cs_change_command() start
> [   60.798736] spidev spi1.3: RXS timed out
> spidev1.3 ioctl success
> no_dma_command() start
> [   61.802032] spidev spi1.1: TXS timed out
> spidev1.1 ioctl success
> cs_change_command() start
> [   62.807525] spidev spi1.3: RXS timed out
> spidev1.3 ioctl success
> no_dma_command() start
> [   63.812042] spidev spi1.1: TXS timed out
> spidev1.1 ioctl success
> ...
> 
> After Patch :
> # ./test_spi
> cs_change_command() start
> spidev1.3 ioctl success
> no_dma_command() start
> spidev1.1 ioctl success
> cs_change_command() start
> spidev1.3 ioctl success
> no_dma_command() start
> spidev1.1 ioctl success
> cs_change_command() start
> spidev1.3 ioctl success
> ...
> 
> v2: uses msg to leave asserted chip select for the current channel
> 
> This is a patch RFC following the bug report :
> 'McSPI hangs with cs_change after "Switch driver to use transfer_one" change'
> http://permalink.gmane.org/gmane.linux.kernel/2056841
> 
> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> index 3d09e0b..1f8903d 100644
> --- a/drivers/spi/spi-omap2-mcspi.c
> +++ b/drivers/spi/spi-omap2-mcspi.c
> @@ -1217,6 +1217,33 @@ out:
>  	return status;
>  }
> 
> +static int omap2_mcspi_prepare_message(struct spi_master *master,
> +				       struct spi_message *msg)
> +{
> +	struct omap2_mcspi	*mcspi = spi_master_get_devdata(master);
> +	struct omap2_mcspi_regs	*ctx = &mcspi->ctx;
> +	struct omap2_mcspi_cs	*cs;
> +

Do we need the pm_runtime_get_sync code here?
See previous commit.

> +	/* Only a single channel can have the FORCE bit enabled
> +	 * in its chconf0 register.
> +	 * Scan all channels and disable them except the current one.
> +	 * A FORCE can remain from a last transfer having cs_change enabled
> +	 */
> +	list_for_each_entry(cs, &ctx->cs, node) {
> +		if (msg->spi->controller_state == cs)
> +			continue;
> +
> +		if ((cs->chconf0 & OMAP2_MCSPI_CHCONF_FORCE)) {
> +			cs->chconf0 &= ~OMAP2_MCSPI_CHCONF_FORCE;
> +			writel_relaxed(cs->chconf0,
> +					cs->base + OMAP2_MCSPI_CHCONF0);
> +			readl_relaxed(cs->base + OMAP2_MCSPI_CHCONF0);
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static int omap2_mcspi_transfer_one(struct spi_master *master,
>  		struct spi_device *spi, struct spi_transfer *t)
>  {
> @@ -1344,6 +1371,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
>  	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
>  	master->setup = omap2_mcspi_setup;
>  	master->auto_runtime_pm = true;
> +	master->prepare_message = omap2_mcspi_prepare_message;
>  	master->transfer_one = omap2_mcspi_transfer_one;
>  	master->set_cs = omap2_mcspi_set_cs;
>  	master->cleanup = omap2_mcspi_cleanup;
> -- 
> 1.9.1
> 

Re: [PATCH v2] spi: omap2-mcspi: disable other channels CHCONF_FORCE in prepare_message

[Neil Armstrong]

On 10/09/2015 05:26 PM, Michael Welling wrote:
> On Fri, Oct 09, 2015 at 03:47:41PM +0200, Neil Armstrong wrote:
>> Since the "Switch driver to use transfer_one" change, the cs_change
>> behavior has changed and a channel chip select can still be
>> asserted when changing channel from a previous last transfer in a
>> message having the cs_change attribute.
>>
>> Since there is no sense having multiple chip select being asserted at the
>> same time, disable all the remaining forced chip selects in a the
>> prepare_message called right before a spi_transfer_one_message call.
>> It ignores the current channel configuration in order to keep the
>> possibility to leave the chip select asserted between messages.
>>
>> It fixes this bug on a DM8168 SoC ES2.1 Soc and an OMAP4 ES2.1 SoC.
>> It was hanging all the other channels transfers when a CHCONF_FORCE
>> is present on the wrong channel.
>>
>> Fixes: b28cb9414db9 ("spi: omap2-mcspi: Switch driver to use transfer_one")
>> Signed-off-by: Neil Armstrong <narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
>> ---
>>  drivers/spi/spi-omap2-mcspi.c | 28 ++++++++++++++++++++++++++++
>>  1 file changed, 28 insertions(+)
>>
>> Test code can be found on :
>> http://pastebin.com/0SrqbGP7
>>
>> Before patch :
>> # ./test_spi
>> cs_change_command() start
>> spidev1.3 ioctl success
>> no_dma_command() start
>> [   59.790069] spidev spi1.1: TXS timed out
>> spidev1.1 ioctl success
>> cs_change_command() start
>> [   60.798736] spidev spi1.3: RXS timed out
>> spidev1.3 ioctl success
>> no_dma_command() start
>> [   61.802032] spidev spi1.1: TXS timed out
>> spidev1.1 ioctl success
>> cs_change_command() start
>> [   62.807525] spidev spi1.3: RXS timed out
>> spidev1.3 ioctl success
>> no_dma_command() start
>> [   63.812042] spidev spi1.1: TXS timed out
>> spidev1.1 ioctl success
>> ...
>>
>> After Patch :
>> # ./test_spi
>> cs_change_command() start
>> spidev1.3 ioctl success
>> no_dma_command() start
>> spidev1.1 ioctl success
>> cs_change_command() start
>> spidev1.3 ioctl success
>> no_dma_command() start
>> spidev1.1 ioctl success
>> cs_change_command() start
>> spidev1.3 ioctl success
>> ...
>>
>> v2: uses msg to leave asserted chip select for the current channel
>>
>> This is a patch RFC following the bug report :
>> 'McSPI hangs with cs_change after "Switch driver to use transfer_one" change'
>> http://permalink.gmane.org/gmane.linux.kernel/2056841
>>
>> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
>> index 3d09e0b..1f8903d 100644
>> --- a/drivers/spi/spi-omap2-mcspi.c
>> +++ b/drivers/spi/spi-omap2-mcspi.c
>> @@ -1217,6 +1217,33 @@ out:
>>  	return status;
>>  }
>>
>> +static int omap2_mcspi_prepare_message(struct spi_master *master,
>> +				       struct spi_message *msg)
>> +{
>> +	struct omap2_mcspi	*mcspi = spi_master_get_devdata(master);
>> +	struct omap2_mcspi_regs	*ctx = &mcspi->ctx;
>> +	struct omap2_mcspi_cs	*cs;
>> +
> 
> Do we need the pm_runtime_get_sync code here?
> See previous commit.
> 

I checked and prepare_message is only called after pm_rumtime_get_sync in __spi_pump_messages()

Neil
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Re: [PATCH v2] spi: omap2-mcspi: disable other channels CHCONF_FORCE in prepare_message

[Michael Welling]

On Fri, Oct 09, 2015 at 05:29:26PM +0200, Neil Armstrong wrote:
> On 10/09/2015 05:26 PM, Michael Welling wrote:
> > On Fri, Oct 09, 2015 at 03:47:41PM +0200, Neil Armstrong wrote:
> >> Since the "Switch driver to use transfer_one" change, the cs_change
> >> behavior has changed and a channel chip select can still be
> >> asserted when changing channel from a previous last transfer in a
> >> message having the cs_change attribute.
> >>
> >> Since there is no sense having multiple chip select being asserted at the
> >> same time, disable all the remaining forced chip selects in a the
> >> prepare_message called right before a spi_transfer_one_message call.
> >> It ignores the current channel configuration in order to keep the
> >> possibility to leave the chip select asserted between messages.
> >>
> >> It fixes this bug on a DM8168 SoC ES2.1 Soc and an OMAP4 ES2.1 SoC.
> >> It was hanging all the other channels transfers when a CHCONF_FORCE
> >> is present on the wrong channel.
> >>
> >> Fixes: b28cb9414db9 ("spi: omap2-mcspi: Switch driver to use transfer_one")
> >> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> >> ---
> >>  drivers/spi/spi-omap2-mcspi.c | 28 ++++++++++++++++++++++++++++
> >>  1 file changed, 28 insertions(+)
> >>
> >> Test code can be found on :
> >> http://pastebin.com/0SrqbGP7
> >>
> >> Before patch :
> >> # ./test_spi
> >> cs_change_command() start
> >> spidev1.3 ioctl success
> >> no_dma_command() start
> >> [   59.790069] spidev spi1.1: TXS timed out
> >> spidev1.1 ioctl success
> >> cs_change_command() start
> >> [   60.798736] spidev spi1.3: RXS timed out
> >> spidev1.3 ioctl success
> >> no_dma_command() start
> >> [   61.802032] spidev spi1.1: TXS timed out
> >> spidev1.1 ioctl success
> >> cs_change_command() start
> >> [   62.807525] spidev spi1.3: RXS timed out
> >> spidev1.3 ioctl success
> >> no_dma_command() start
> >> [   63.812042] spidev spi1.1: TXS timed out
> >> spidev1.1 ioctl success
> >> ...
> >>
> >> After Patch :
> >> # ./test_spi
> >> cs_change_command() start
> >> spidev1.3 ioctl success
> >> no_dma_command() start
> >> spidev1.1 ioctl success
> >> cs_change_command() start
> >> spidev1.3 ioctl success
> >> no_dma_command() start
> >> spidev1.1 ioctl success
> >> cs_change_command() start
> >> spidev1.3 ioctl success
> >> ...
> >>
> >> v2: uses msg to leave asserted chip select for the current channel
> >>
> >> This is a patch RFC following the bug report :
> >> 'McSPI hangs with cs_change after "Switch driver to use transfer_one" change'
> >> http://permalink.gmane.org/gmane.linux.kernel/2056841
> >>
> >> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> >> index 3d09e0b..1f8903d 100644
> >> --- a/drivers/spi/spi-omap2-mcspi.c
> >> +++ b/drivers/spi/spi-omap2-mcspi.c
> >> @@ -1217,6 +1217,33 @@ out:
> >>  	return status;
> >>  }
> >>
> >> +static int omap2_mcspi_prepare_message(struct spi_master *master,
> >> +				       struct spi_message *msg)
> >> +{
> >> +	struct omap2_mcspi	*mcspi = spi_master_get_devdata(master);
> >> +	struct omap2_mcspi_regs	*ctx = &mcspi->ctx;
> >> +	struct omap2_mcspi_cs	*cs;
> >> +
> > 
> > Do we need the pm_runtime_get_sync code here?
> > See previous commit.
> > 
> 
> I checked and prepare_message is only called after pm_rumtime_get_sync in __spi_pump_messages()

Okay, I see it now.

Reviewed-by: Michael Welling <mwelling@ieee.org>

> 
> Neil