RE: [PATCH v10 05/12] dmaengine: dma: imx-sdma: add fw_loaded and is_ram_script

[Robin Gong <yibin.gong@xxxxxxx>]

On 2020/07/23 17:04 Frieder Schrempf <frieder.schrempf@xxxxxxxxxx> wrote: 
> Hi Robin,
> 
> On 30.06.20 15:31, Robin Gong wrote:
> > Add 'fw_loaded' and 'is_ram_script' to check if the script used by
> > channel is ram script and it's loaded or not, so that could prevent
> > meaningless following malloc dma descriptor and bd allocate in
> > sdma_transfer_init(), otherwise memory may be consumed out potentially
> > without free in case that spi fallback into pio while dma transfer
> > failed by sdma firmware not ready(next ERR009165 patch depends on sdma
> RAM scripts/firmware).
> >
> > Signed-off-by: Robin Gong <yibin.gong@xxxxxxx>
> > Acked-By: Vinod Koul <vkoul@xxxxxxxxxx>
> > ---
> >   drivers/dma/imx-sdma.c | 13 +++++++++++++
> >   1 file changed, 13 insertions(+)
> >
> > diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index
> > 5411e01e..ce1c83e 100644
> > --- a/drivers/dma/imx-sdma.c
> > +++ b/drivers/dma/imx-sdma.c
> > @@ -379,6 +379,7 @@ struct sdma_channel {
> >   	enum dma_status			status;
> >   	struct imx_dma_data		data;
> >   	struct work_struct		terminate_worker;
> > +	bool				is_ram_script;
> >   };
> >
> >   #define IMX_DMA_SG_LOOP		BIT(0)
> > @@ -443,6 +444,7 @@ struct sdma_engine {
> >   	struct sdma_buffer_descriptor	*bd0;
> >   	/* clock ratio for AHB:SDMA core. 1:1 is 1, 2:1 is 0*/
> >   	bool				clk_ratio;
> > +	bool                            fw_loaded;
> >   };
> >
> >   static int sdma_config_write(struct dma_chan *chan, @@ -929,6 +931,7
> > @@ static void sdma_get_pc(struct sdma_channel *sdmac,
> >   	case IMX_DMATYPE_SSI_DUAL:
> >   		per_2_emi = sdma->script_addrs->ssish_2_mcu_addr;
> >   		emi_2_per = sdma->script_addrs->mcu_2_ssish_addr;
> > +		sdmac->is_ram_script = true;
> >   		break;
> >   	case IMX_DMATYPE_SSI_SP:
> >   	case IMX_DMATYPE_MMC:
> > @@ -943,6 +946,7 @@ static void sdma_get_pc(struct sdma_channel
> *sdmac,
> >   		per_2_emi = sdma->script_addrs->asrc_2_mcu_addr;
> >   		emi_2_per = sdma->script_addrs->asrc_2_mcu_addr;
> >   		per_2_per = sdma->script_addrs->per_2_per_addr;
> > +		sdmac->is_ram_script = true;
> >   		break;
> >   	case IMX_DMATYPE_ASRC_SP:
> >   		per_2_emi = sdma->script_addrs->shp_2_mcu_addr;
> > @@ -1339,6 +1343,11 @@ static struct sdma_desc
> *sdma_transfer_init(struct sdma_channel *sdmac,
> >   {
> >   	struct sdma_desc *desc;
> >
> > +	if (!sdmac->sdma->fw_loaded && sdmac->is_ram_script) {
> > +		dev_err(sdmac->sdma->dev, "sdma firmware not ready!\n");
> > +		goto err_out;
> > +	}
> 
> I tried your v10 patches on next-20200722 with i.MX8MM and it mostly
> seems to work fine.
> 
> When I tried first, I had the imx-sdma driver compiled into the kernel, so it
> didn't load the firmware and fell back to the ROM scripts.
> With this, SPI transactions work just fine, but I got the above error message
> printed continuously when sending data in SPI3 via spidev.
That's caused by you didn't load ram firmware as this patch set described.
Please follow below steps to load firmware manually if you don't want to
use NXP official Yocto release package:

1. Get sdma firmware from below linux-firmware and copy it to your
local rootfs /lib/firmware/imx/sdma.
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/imx/sdma
2. Load firmware manually:
        echo 1 > /sys/$DEVPATH/loading
        cat $MY_FW_DIR/$FIRMWARE > /sys/$DEVPATH/data
        echo 0 > /sys/$DEVPATH/loading
Please refer to Documentation/driver-api/firmware/fallback-mechanisms.rst
and load the firmware in 60s (firmware fallback loading timeout) from kernel
boot up.

> 
> When I build imx-sdma as a module, the firmware is loaded correctly and
> everything works as expected.
I guess that's not related with sdma building as module. If sdma build as
module, spi will fall to pio mode at spi-imx driver probe phase so that the above
warning log never to be walked. Would you please add some debug info to double
confirm?  
> 
> Can you have a look at this and provide a fix?
> 
> Thanks,
> Frieder