spi: rockchip: limit transfers to (64K - 1) bytes
diff mbox

Message ID 1468546259-136659-1-git-send-email-briannorris@chromium.org
State New
Headers show

Commit Message

Brian Norris July 15, 2016, 1:30 a.m. UTC
The Rockchip SPI controller's length register only supports 16-bits,
yielding a maximum length of 64KiB (the CTRLR1 register holds "length -
1"). Trying to transfer more than that (e.g., with a large SPI flash
read) will cause the driver to hang.

Now, it seems that while theoretically we should be able to program
CTRLR1 with 0xffff, and get a 64KiB transfer, but that also seems to
cause the core to choke, so stick with a maximum of 64K - 1 bytes --
i.e., 0xffff.

Signed-off-by: Brian Norris <briannorris@chromium.org>
---
 drivers/spi/spi-rockchip.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Comments

Shawn Lin July 15, 2016, 1:56 a.m. UTC | #1
+ huibing

在 2016/7/15 9:30, Brian Norris 写道:
> The Rockchip SPI controller's length register only supports 16-bits,
> yielding a maximum length of 64KiB (the CTRLR1 register holds "length -
> 1"). Trying to transfer more than that (e.g., with a large SPI flash
> read) will cause the driver to hang.

Brian, are you using dma or pio?

 From huibing's feedback for rk3399, you can see...

root@rk3399:/ # echo read 0 1 0x10001 > /sys/slt/SPI.0/SPI.0 

[148360.004332] f0041200:       DMAMOV CCR 0x804200
[148360.004772] f0041206:       DMAMOV SAR 0xff1d0800
[148360.005161] f004120c:       DMAMOV DAR 0xc9f60000
[148360.005549] f0041212:       DMALP_0 255
[148360.005866] f0041214:       DMALP_1 255
[148360.006178] f0041216:       DMAWFPB 13
[148360.006483] f0041218:       DMALDPB 13
[148360.006788] f004121a:       DMASTA
[148360.007061] f004121b:       DMAFLUSHP 13
[148360.007380] f004121d:       DMALPENDA_1 bjmpto_7
[148360.007763] f004121f:       DMALPENDA_0 bjmpto_b
[148360.008144] f0041221:       DMAWFPB 13
[148360.008448] f0041223:       DMALDPB 13
[148360.008752] f0041225:       DMASTA
[148360.009026] f0041226:       DMAFLUSHP 13
[148360.009344] f0041228:       DMASEV 1
[148360.009633] f004122a:       DMAEND
[148360.147993] slt_spi_test spi32766.0: SPI transfer timed out
[148360.148653] spi read 65537*1 cost 144493us speed:453KB/S
root@rk3399:/ #
root@rk3399:/ # echo read 0 1 0x10000 > /sys/slt/SPI.0/SPI.0 

[148365.172429] f0041200:       DMAMOV CCR 0x804200
[148365.172863] f0041206:       DMAMOV SAR 0xff1d0800
[148365.173252] f004120c:       DMAMOV DAR 0xc9f90000
[148365.173641] f0041212:       DMALP_0 255
[148365.173958] f0041214:       DMALP_1 255
[148365.174270] f0041216:       DMAWFPB 13
[148365.174574] f0041218:       DMALDPB 13
[148365.174878] f004121a:       DMASTA
[148365.175152] f004121b:       DMAFLUSHP 13
[148365.175471] f004121d:       DMALPENDA_1 bjmpto_7
[148365.175852] f004121f:       DMALPENDA_0 bjmpto_b
[148365.176234] f0041221:       DMASEV 1
[148365.176522] f0041223:       DMAEND
[148365.207421] spi read 65536*1 cost 35144us speed:1864KB/S



>
> Now, it seems that while theoretically we should be able to program
> CTRLR1 with 0xffff, and get a 64KiB transfer, but that also seems to
> cause the core to choke, so stick with a maximum of 64K - 1 bytes --
> i.e., 0xffff.
>
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---
>  drivers/spi/spi-rockchip.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
>
> diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
> index d840324bcc9f..0f89c2169c24 100644
> --- a/drivers/spi/spi-rockchip.c
> +++ b/drivers/spi/spi-rockchip.c
> @@ -142,6 +142,12 @@
>  /* sclk_out: spi master internal logic in rk3x can support 50Mhz */
>  #define MAX_SCLK_OUT		50000000
>
> +/*
> + * SPI_CTRLR1 is 16-bits, so we should support lengths of 0xffff + 1. However,
> + * the controller seems to hang when given 0x10000, so stick with this for now.
> + */
> +#define ROCKCHIP_SPI_MAX_TRANLEN		0xffff
> +
>  enum rockchip_ssi_type {
>  	SSI_MOTO_SPI = 0,
>  	SSI_TI_SSP,
> @@ -573,6 +579,11 @@ static void rockchip_spi_config(struct rockchip_spi *rs)
>  	dev_dbg(rs->dev, "cr0 0x%x, div %d\n", cr0, div);
>  }
>
> +static size_t rockchip_spi_max_transfer_size(struct spi_device *spi)
> +{
> +	return ROCKCHIP_SPI_MAX_TRANLEN;
> +}
> +
>  static int rockchip_spi_transfer_one(
>  		struct spi_master *master,
>  		struct spi_device *spi,
> @@ -589,6 +600,11 @@ static int rockchip_spi_transfer_one(
>  		return -EINVAL;
>  	}
>
> +	if (xfer->len > ROCKCHIP_SPI_MAX_TRANLEN) {
> +		dev_err(rs->dev, "Transfer is too long (%d)\n", xfer->len);
> +		return -EINVAL;
> +	}
> +
>  	rs->speed = xfer->speed_hz;
>  	rs->bpw = xfer->bits_per_word;
>  	rs->n_bytes = rs->bpw >> 3;
> @@ -730,6 +746,7 @@ static int rockchip_spi_probe(struct platform_device *pdev)
>  	master->prepare_message = rockchip_spi_prepare_message;
>  	master->unprepare_message = rockchip_spi_unprepare_message;
>  	master->transfer_one = rockchip_spi_transfer_one;
> +	master->max_transfer_size = rockchip_spi_max_transfer_size;
>  	master->handle_err = rockchip_spi_handle_err;
>
>  	rs->dma_tx.ch = dma_request_chan(rs->dev, "tx");
>
Brian Norris July 15, 2016, 2:31 a.m. UTC | #2
Hi Shawn,

On Fri, Jul 15, 2016 at 09:56:59AM +0800, Shawn Lin wrote:
> 在 2016/7/15 9:30, Brian Norris 写道:
> >The Rockchip SPI controller's length register only supports 16-bits,
> >yielding a maximum length of 64KiB (the CTRLR1 register holds "length -
> >1"). Trying to transfer more than that (e.g., with a large SPI flash
> >read) will cause the driver to hang.
> 
> Brian, are you using dma or pio?

I forgot to mention, I'm using PIO. (The rk3399.dts in linux-next
doesn't even have the 'dma{s,-names}' properties listed for spi[0-5].)

> From huibing's feedback for rk3399, you can see...
> 
> root@rk3399:/ # echo read 0 1 0x10001 > /sys/slt/SPI.0/SPI.0

I don't know what that file is, but presumably it's some kind of bare
SPI test interface you have in your private tree?

> [148360.004332] f0041200:       DMAMOV CCR 0x804200
> [148360.004772] f0041206:       DMAMOV SAR 0xff1d0800
> [148360.005161] f004120c:       DMAMOV DAR 0xc9f60000
> [148360.005549] f0041212:       DMALP_0 255
> [148360.005866] f0041214:       DMALP_1 255
> [148360.006178] f0041216:       DMAWFPB 13
> [148360.006483] f0041218:       DMALDPB 13
> [148360.006788] f004121a:       DMASTA
> [148360.007061] f004121b:       DMAFLUSHP 13
> [148360.007380] f004121d:       DMALPENDA_1 bjmpto_7
> [148360.007763] f004121f:       DMALPENDA_0 bjmpto_b
> [148360.008144] f0041221:       DMAWFPB 13
> [148360.008448] f0041223:       DMALDPB 13
> [148360.008752] f0041225:       DMASTA
> [148360.009026] f0041226:       DMAFLUSHP 13
> [148360.009344] f0041228:       DMASEV 1
> [148360.009633] f004122a:       DMAEND
> [148360.147993] slt_spi_test spi32766.0: SPI transfer timed out
> [148360.148653] spi read 65537*1 cost 144493us speed:453KB/S

And this means a 64KiB + 1 transfer using DMA timed out?

> root@rk3399:/ #
> root@rk3399:/ # echo read 0 1 0x10000 > /sys/slt/SPI.0/SPI.0
> 
> [148365.172429] f0041200:       DMAMOV CCR 0x804200
> [148365.172863] f0041206:       DMAMOV SAR 0xff1d0800
> [148365.173252] f004120c:       DMAMOV DAR 0xc9f90000
> [148365.173641] f0041212:       DMALP_0 255
> [148365.173958] f0041214:       DMALP_1 255
> [148365.174270] f0041216:       DMAWFPB 13
> [148365.174574] f0041218:       DMALDPB 13
> [148365.174878] f004121a:       DMASTA
> [148365.175152] f004121b:       DMAFLUSHP 13
> [148365.175471] f004121d:       DMALPENDA_1 bjmpto_7
> [148365.175852] f004121f:       DMALPENDA_0 bjmpto_b
> [148365.176234] f0041221:       DMASEV 1
> [148365.176522] f0041223:       DMAEND
> [148365.207421] spi read 65536*1 cost 35144us speed:1864KB/S

And a 64KiB transfer using DMA completed successfully?

So maybe there's a driver bug in the PIO path that gives us an
off-by-one error. I poked around a bit and couldn't figure out anything,
so I sent this. Technically, this patch is still valid (even if not
optimal) for the DMA case too...

If you can't figure out what the difference is, and you really don't
want to unnecessarily limit the DMA case, then a last resort hack could
be to say:

static size_t rockchip_spi_max_transfer_size(struct spi_device *device)
{
	if (using dma) // this is obviously pseudocode
		return SZ_64K;
	else
		return SZ_64K - 1;
}

or something like that.

Brian
Shawn Lin July 15, 2016, 2:42 a.m. UTC | #3
在 2016/7/15 10:31, Brian Norris 写道:
> Hi Shawn,
>
> On Fri, Jul 15, 2016 at 09:56:59AM +0800, Shawn Lin wrote:
>> 在 2016/7/15 9:30, Brian Norris 写道:
>>> The Rockchip SPI controller's length register only supports 16-bits,
>>> yielding a maximum length of 64KiB (the CTRLR1 register holds "length -
>>> 1"). Trying to transfer more than that (e.g., with a large SPI flash
>>> read) will cause the driver to hang.
>>
>> Brian, are you using dma or pio?
>
> I forgot to mention, I'm using PIO. (The rk3399.dts in linux-next
> doesn't even have the 'dma{s,-names}' properties listed for spi[0-5].)

okay.

>
>> From huibing's feedback for rk3399, you can see...
>>
>> root@rk3399:/ # echo read 0 1 0x10001 > /sys/slt/SPI.0/SPI.0
>
> I don't know what that file is, but presumably it's some kind of bare
> SPI test interface you have in your private tree?

yes.

>
>> [148360.004332] f0041200:       DMAMOV CCR 0x804200
>> [148360.004772] f0041206:       DMAMOV SAR 0xff1d0800
>> [148360.005161] f004120c:       DMAMOV DAR 0xc9f60000
>> [148360.005549] f0041212:       DMALP_0 255
>> [148360.005866] f0041214:       DMALP_1 255
>> [148360.006178] f0041216:       DMAWFPB 13
>> [148360.006483] f0041218:       DMALDPB 13
>> [148360.006788] f004121a:       DMASTA
>> [148360.007061] f004121b:       DMAFLUSHP 13
>> [148360.007380] f004121d:       DMALPENDA_1 bjmpto_7
>> [148360.007763] f004121f:       DMALPENDA_0 bjmpto_b
>> [148360.008144] f0041221:       DMAWFPB 13
>> [148360.008448] f0041223:       DMALDPB 13
>> [148360.008752] f0041225:       DMASTA
>> [148360.009026] f0041226:       DMAFLUSHP 13
>> [148360.009344] f0041228:       DMASEV 1
>> [148360.009633] f004122a:       DMAEND
>> [148360.147993] slt_spi_test spi32766.0: SPI transfer timed out
>> [148360.148653] spi read 65537*1 cost 144493us speed:453KB/S
>
> And this means a 64KiB + 1 transfer using DMA timed out?

Right.

>
>> root@rk3399:/ #
>> root@rk3399:/ # echo read 0 1 0x10000 > /sys/slt/SPI.0/SPI.0
>>
>> [148365.172429] f0041200:       DMAMOV CCR 0x804200
>> [148365.172863] f0041206:       DMAMOV SAR 0xff1d0800
>> [148365.173252] f004120c:       DMAMOV DAR 0xc9f90000
>> [148365.173641] f0041212:       DMALP_0 255
>> [148365.173958] f0041214:       DMALP_1 255
>> [148365.174270] f0041216:       DMAWFPB 13
>> [148365.174574] f0041218:       DMALDPB 13
>> [148365.174878] f004121a:       DMASTA
>> [148365.175152] f004121b:       DMAFLUSHP 13
>> [148365.175471] f004121d:       DMALPENDA_1 bjmpto_7
>> [148365.175852] f004121f:       DMALPENDA_0 bjmpto_b
>> [148365.176234] f0041221:       DMASEV 1
>> [148365.176522] f0041223:       DMAEND
>> [148365.207421] spi read 65536*1 cost 35144us speed:1864KB/S
>
> And a 64KiB transfer using DMA completed successfully?

yup.

>
> So maybe there's a driver bug in the PIO path that gives us an
> off-by-one error. I poked around a bit and couldn't figure out anything,
> so I sent this. Technically, this patch is still valid (even if not
> optimal) for the DMA case too...

Huibing is using pio to test this case, and we still achieve it
successfully? That means there may be some minor diff for the pio
path between your chromium repo and my local branch.

>
> If you can't figure out what the difference is, and you really don't
> want to unnecessarily limit the DMA case, then a last resort hack could
> be to say:
>

Could you get spi-rockchip.c of rockchip local kernel 4.4 from Caesar
to see if you could transfer 64KB with the one we're using?


> static size_t rockchip_spi_max_transfer_size(struct spi_device *device)
> {
> 	if (using dma) // this is obviously pseudocode
> 		return SZ_64K;
> 	else
> 		return SZ_64K - 1;
> }
>
> or something like that.
>
> Brian
>
>
>
Brian Norris July 15, 2016, 3:09 a.m. UTC | #4
On Fri, Jul 15, 2016 at 10:42:55AM +0800, Shawn Lin wrote:
> 在 2016/7/15 10:31, Brian Norris 写道:
> >So maybe there's a driver bug in the PIO path that gives us an
> >off-by-one error. I poked around a bit and couldn't figure out anything,
> >so I sent this. Technically, this patch is still valid (even if not
> >optimal) for the DMA case too...
> 
> Huibing is using pio to test this case, and we still achieve it
> successfully?

Are you saying Huibing has tested PIO with 64KB transfers, or is that a
question? If the former, it'd be great if he can publish the differences
between his kernel and upstream to produce this.

> That means there may be some minor diff for the pio
> path between your chromium repo and my local branch.

This is an upstream kernel mailing list. I'd expect we can agree to test
on an upstream kernel...

> >want to unnecessarily limit the DMA case, then a last resort hack could
> >be to say:
> >
> 
> Could you get spi-rockchip.c of rockchip local kernel 4.4 from Caesar
> to see if you could transfer 64KB with the one we're using?

I just compared with some (possibly old) copy of your vendor-kernel
driver, and there are a few moderate differences. I didn't test it yet.
I'd think the onus is on you to publish your changes though, if you
think you've fixed things in your own private tree...but I'm willing to
test any changes you recommend.

Brian

Patch
diff mbox

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index d840324bcc9f..0f89c2169c24 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -142,6 +142,12 @@ 
 /* sclk_out: spi master internal logic in rk3x can support 50Mhz */
 #define MAX_SCLK_OUT		50000000
 
+/*
+ * SPI_CTRLR1 is 16-bits, so we should support lengths of 0xffff + 1. However,
+ * the controller seems to hang when given 0x10000, so stick with this for now.
+ */
+#define ROCKCHIP_SPI_MAX_TRANLEN		0xffff
+
 enum rockchip_ssi_type {
 	SSI_MOTO_SPI = 0,
 	SSI_TI_SSP,
@@ -573,6 +579,11 @@  static void rockchip_spi_config(struct rockchip_spi *rs)
 	dev_dbg(rs->dev, "cr0 0x%x, div %d\n", cr0, div);
 }
 
+static size_t rockchip_spi_max_transfer_size(struct spi_device *spi)
+{
+	return ROCKCHIP_SPI_MAX_TRANLEN;
+}
+
 static int rockchip_spi_transfer_one(
 		struct spi_master *master,
 		struct spi_device *spi,
@@ -589,6 +600,11 @@  static int rockchip_spi_transfer_one(
 		return -EINVAL;
 	}
 
+	if (xfer->len > ROCKCHIP_SPI_MAX_TRANLEN) {
+		dev_err(rs->dev, "Transfer is too long (%d)\n", xfer->len);
+		return -EINVAL;
+	}
+
 	rs->speed = xfer->speed_hz;
 	rs->bpw = xfer->bits_per_word;
 	rs->n_bytes = rs->bpw >> 3;
@@ -730,6 +746,7 @@  static int rockchip_spi_probe(struct platform_device *pdev)
 	master->prepare_message = rockchip_spi_prepare_message;
 	master->unprepare_message = rockchip_spi_unprepare_message;
 	master->transfer_one = rockchip_spi_transfer_one;
+	master->max_transfer_size = rockchip_spi_max_transfer_size;
 	master->handle_err = rockchip_spi_handle_err;
 
 	rs->dma_tx.ch = dma_request_chan(rs->dev, "tx");