| Message ID | 1449557030-27525-6-git-send-email-anton.bondarenko.sama@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Dec 08, 2015 at 07:43:47AM +0100, Anton Bondarenko wrote: > Also removing change introduced in f6ee9b582d2db652497b73c1f117591dfb6d3a90 > since this change only fix usecases with transfer size from 33 to 128 bytes > and doesn't fix 129 bytes and bigger. This is a bug fix for stable but it's randomly in the middle of the patch series so I can't apply it as such :( Please send this as a bug fix suitable for sending to Linus. Please also include human readable descriptions of things like commits and issues being discussed in e-mail in your mails, this makes them much easier for humans to read especially when they have no internet access. I do frequently catch up on my mail on flights or while otherwise travelling so this is even more pressing for me than just being about making things a bit easier to read.
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index d98c33c..50e0a79 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -204,8 +204,8 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi, { struct spi_imx_data *spi_imx = spi_master_get_devdata(master); - if (spi_imx->dma_is_inited && - transfer->len > spi_imx->wml * sizeof(u32)) + if (spi_imx->dma_is_inited && transfer->len >= spi_imx->wml && + (transfer->len % spi_imx->wml) == 0) return true; return false; }
RX DMA tail data handling doesn't work correctly in many cases with current implementation. It happens because SPI core was setup to generates both RX and RX TAIL events. And RX TAIL event does not work correctly. This can be easily verified by sending SPI transaction with size modulus WML(32 in our case) not equal 0. Also removing change introduced in f6ee9b582d2db652497b73c1f117591dfb6d3a90 since this change only fix usecases with transfer size from 33 to 128 bytes and doesn't fix 129 bytes and bigger. This is output from transaction with len 138 bytes in loopback mode at 10Mhz: TX0000: a3 97 a2 55 53 be f1 fc f9 79 6b 52 14 13 e9 e2 TX0010: 2d 51 8e 1f 56 08 57 27 a7 05 d4 d0 52 82 77 75 TX0020: 1b 99 4a ed 58 3d 6a 52 36 d5 24 4a 68 8e ad 95 TX0030: 5f 3c 35 b5 c4 8c dd 6c 11 32 3d e2 b4 b4 59 cf TX0040: ce 23 3d 27 df a7 f9 96 fc 1e e0 66 2c 0e 7b 8c TX0050: ca 30 42 8f bc 9f 7b ce d1 b8 b1 87 ec 8a d6 bb TX0060: 2e 15 63 0e 3c dc a4 3a 7a 06 20 a7 93 1b 34 dd TX0070: 4c f5 ec 88 96 68 d6 68 a0 09 6f 8e 93 47 c9 41 TX0080: db ac cf 97 89 f3 51 05 79 71 RX0000: a3 97 a2 55 53 be f1 fc f9 79 6b 52 14 13 e9 e2 RX0010: 2d 51 8e 1f 56 08 57 27 a7 05 d4 d0 52 82 77 75 RX0020: 1b 99 4a ed 58 3d 6a 52 36 d5 24 4a 68 8e ad 95 RX0030: 5f 3c 35 00 00 b5 00 00 00 c4 00 00 8c 00 00 dd RX0040: 6c 11 32 3d e2 b4 b4 59 cf ce 23 3d 27 df a7 f9 RX0050: 96 fc 1e e0 66 2c 0e 7b 8c ca 30 42 8f 1f 1f bc RX0060: 9f 7b ce d1 b8 b1 87 ec 8a d6 bb 2e 15 63 0e ed RX0070: ed 3c 58 58 58 dc 3d 3d a4 6a 6a 3a 52 52 7a 36 RX0080: 06 20 a7 93 1b 34 dd 4c f5 ec Zeros at offset 33 and 34 caused by reading empty RX FIFO which not possible if DMA RX read was triggered by RX event. This mean DMA was triggered by RX TAIL event. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> --- drivers/spi/spi-imx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)