On Mon, Dec 10, 2012 at 8:49 PM, Jack Mitchell <ml@xxxxxxxxxxxxxxxxxxx> wrote: > On 10/12/12 14:59, Felipe Balbi wrote: >> >> Hi, >> >> On Mon, Dec 10, 2012 at 02:50:16PM +0000, Jack Mitchell wrote: >>>> >>>> On Mon, Dec 10, 2012 at 01:23:09PM +0000, Jack Mitchell wrote: >>>>> >>>>> Hi, >>>>> >>>>> I am currently having issues with the SPI driver on the beaglebone >>>>> using the 3.7-rc8 kernel[1]. I have probed the SPI pins and I have >>>>> found that writing works however reading doesn't. When using DMA the >>>>> program seems to lock hard and no data is sent on the bus. I am >>>>> testing the bus using spidev and the spidev_test[2] application, >>>>> however I first came across spi issues with a custom spi driver which >>>>> stopped working when I transitioned from 3.2-psp to 3.7-rc8. >>>>> >>>>> The current output I am seeing from the spidev_test program is just a >>>>> series of 0x00 data, which looks to me like no data is getting in at >>>>> all. The spidev_test program is not using DMA as the buffer size is >>>>> too low, so I forced the dma on when buffer size is > 1 and the >>>>> program hangs hard with the system still responding to other >>>>> commands.I have briged the pins 18 and 21 on the BeagleBone P9 >>>>> header. >>>>> >>>>> Has anyone seen issues like this, or if not if someone could please >>>>> test the latest 3.7-rc8 from [1] and let me know if it works for them >>>>> and the issue is at my end. >>>>> >>>>> To get spidev working with devicetree I applied the patch from [3] >>>>> and changed the dtb as in the patch pasted below. >>>>> >>>>> [1] https://github.com/beagleboard/kernel/tree/3.7 >>>>> [2] http://lxr.linux.no/#linux+v3.6.9/Documentation/spi/spidev_test.c >>>>> [3] >>>>> http://www.mail-archive.com/spi-devel-general@xxxxxxxxxxxxxxxxxxxxx/msg09958.html >>>> >>>> do you have any debugging output from that driver ? It would be cool to >>>> see if DMA is at least being kicked properly for small transfers. >>> >>> When I run the spidev program with dma for transfers > 1, the program >>> hangs and the only output in dmesg is: >>> >>> [ 12.613952] libphy: 4a101000.mdio:00 - Link is Up - 100/Full <---- >>> Last line from initial log in [2] >>> [ 47.669202] spidev spi1.0: setup: speed 24000000, sample leading >>> edge, clk normal >>> [ 47.669246] spidev spi1.0: setup mode 0, 8 bits/w, 24000000 Hz max --> >>> 0 >>> [ 47.669260] spidev spi1.0: spi mode 00 >>> [ 47.669283] spidev spi1.0: setup: speed 24000000, sample leading >>> edge, clk normal >>> [ 47.669300] spidev spi1.0: setup mode 0, 16 bits/w, 24000000 Hz max >>> --> 0 >>> [ 47.669312] spidev spi1.0: 16 bits per word >>> [ 47.669330] spidev spi1.0: setup: speed 24000000, sample leading >>> edge, clk normal >>> [ 47.669347] spidev spi1.0: setup mode 0, 16 bits/w, 24000000 Hz max >>> --> 0 >>> [ 47.669358] spidev spi1.0: 24000000 Hz (max) >>> [ 47.673811] spidev spi1.0: setup: speed 24000000, sample leading >>> edge, clk normal >>> >>> The initial dmesg statup log is at [2]. >> >> can you apply the debugging patch below to spi driver and show me the >> output again ? >> >> Note that I'm allowing DMA for as small as 1-byte transfers (as you >> needed) and I'm also disabling DMA Request line before calling >> complete() as I think the current way could race, but likely wouldn't >> cause issues. Anyway, please show me the output. >> >> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c >> index 3542fdc..d2b1af2 100644 >> --- a/drivers/spi/spi-omap2-mcspi.c >> +++ b/drivers/spi/spi-omap2-mcspi.c >> @@ -108,7 +108,7 @@ struct omap2_mcspi_dma { >> /* use PIO for small transfers, avoiding DMA setup/teardown overhead and >> * cache operations; better heuristics consider wordsize and bitrate. >> */ >> -#define DMA_MIN_BYTES 160 >> +#define DMA_MIN_BYTES 1 >> /* >> @@ -298,10 +298,11 @@ static void omap2_mcspi_rx_callback(void *data) >> struct omap2_mcspi *mcspi = spi_master_get_devdata(spi->master); >> struct omap2_mcspi_dma *mcspi_dma = >> &mcspi->dma_channels[spi->chip_select]; >> - complete(&mcspi_dma->dma_rx_completion); >> - >> /* We must disable the DMA RX request */ >> + dev_info(&spi->dev, "Disabling RX Request Line\n"); >> omap2_mcspi_set_dma_req(spi, 1, 0); >> + >> + complete(&mcspi_dma->dma_rx_completion); >> } >> static void omap2_mcspi_tx_callback(void *data) >> @@ -310,10 +311,11 @@ static void omap2_mcspi_tx_callback(void *data) >> struct omap2_mcspi *mcspi = spi_master_get_devdata(spi->master); >> struct omap2_mcspi_dma *mcspi_dma = >> &mcspi->dma_channels[spi->chip_select]; >> - complete(&mcspi_dma->dma_tx_completion); >> - >> /* We must disable the DMA TX request */ >> + dev_info(&spi->dev, "Disabling TX Request Line\n"); >> omap2_mcspi_set_dma_req(spi, 0, 0); >> + >> + complete(&mcspi_dma->dma_tx_completion); >> } >> static void omap2_mcspi_tx_dma(struct spi_device *spi, >> @@ -328,6 +330,7 @@ static void omap2_mcspi_tx_dma(struct spi_device *spi, >> void __iomem *chstat_reg; >> struct omap2_mcspi_cs *cs = spi->controller_state; >> + dev_info(&spi->dev, "kicking TX DMA\n"); >> mcspi = spi_master_get_devdata(spi->master); >> mcspi_dma = &mcspi->dma_channels[spi->chip_select]; >> count = xfer->len; >> @@ -359,7 +362,9 @@ static void omap2_mcspi_tx_dma(struct spi_device *spi, >> dma_async_issue_pending(mcspi_dma->dma_tx); >> omap2_mcspi_set_dma_req(spi, 0, 1); >> + dev_info(&spi->dev, "Waiting for TX Completion\n"); >> wait_for_completion(&mcspi_dma->dma_tx_completion); >> + dev_info(&spi->dev, "TX Completed\n"); >> dma_unmap_single(mcspi->dev, xfer->tx_dma, count, >> DMA_TO_DEVICE); >> @@ -392,6 +397,7 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct >> spi_transfer *xfer, >> word_len = cs->word_len; >> l = mcspi_cached_chconf0(spi); >> + dev_info(&spi->dev, "kicking RX DMA\n"); >> if (word_len <= 8) >> element_count = count; >> else if (word_len <= 16) >> @@ -428,7 +434,9 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct >> spi_transfer *xfer, >> dma_async_issue_pending(mcspi_dma->dma_rx); >> omap2_mcspi_set_dma_req(spi, 1, 1); >> + dev_info(&spi->dev, "Waiting for RX Completion\n"); >> wait_for_completion(&mcspi_dma->dma_rx_completion); >> + dev_info(&spi->dev, "RX Completed\n"); >> dma_unmap_single(mcspi->dev, xfer->rx_dma, count, >> DMA_FROM_DEVICE); >> omap2_mcspi_set_enable(spi, 0); >> >>>> It would also be nice to have a clear picture of what "custom spi >>>> driver" you're talking about. >>> >>> The custom SPI driver is for connecting and reading registers from an >>> in house FPGA design and can be found at [1]. It's fairly rudimentary >>> and also in the development stages, I'm very new to Linux kernel >>> programming so please take that into account :) >> >> no problem ;-) >> >>> However it did work flawlessly with 3.2-psp. >> >> yeah, it could be some regression introduced somewhere, or just a bugfix >> which was done on 3.2-psp and was missed upstream... annoying when those >> happen :-p >> Can you try the following git://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc.git spi-next Alternatively you can use the linux-next. And let me know if you still see the issue. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
