RE: [PATCH v14 05/12] dmaengine: dma: imx-sdma: add fw_loaded and is_ram_script

[Robin Gong <yibin.gong@nxp.com>]

On 09/07/21 17:25 Lucas Stach <l.stach@pengutronix.de> wrote:
> Am Mittwoch, dem 07.04.2021 um 23:30 +0800 schrieb Robin Gong:
> > 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@nxp.com>
> > Acked-by: Vinod Koul <vkoul@kernel.org>
> > ---
> >  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
> > 1c636d2..78dcfe2 100644
> > --- a/drivers/dma/imx-sdma.c
> > +++ b/drivers/dma/imx-sdma.c
> > @@ -381,6 +381,7 @@ 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)
> > @@ -444,6 +445,7 @@ 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, @@ -899,6 +901,7
> > @@ 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:
> > @@ -913,6 +916,7 @@ 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;
> > @@ -1309,6 +1313,11 @@ 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_warn_once(sdmac->sdma->dev, "sdma firmware not ready!\n");
> > +		goto err_out;
> > +	}
> > +
> >  	desc = kzalloc((sizeof(*desc)), GFP_NOWAIT);
> >  	if (!desc)
> >  		goto err_out;
> > @@ -1559,6 +1568,8 @@ static int sdma_config_write(struct dma_chan
> > *chan,  {
> >  	struct sdma_channel *sdmac = to_sdma_chan(chan);
> >
> > +	sdmac->is_ram_script = false;
> > +
> While it's working correctly, I find it confusing to have this initialization at this
> point in the code. Please fold this into sdma_get_pc(), where it gets changed as
> needed.
Here 'is_ram_script = false' just clear is_ram_script so that the later sdma_get_pc()
could set is_ram_script correctly if it's a ram script. Yes, move it to early part of sdma_get_pc
also works.

> 
> Other than this small issue, this patch is:
> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> 
> >  	if (direction == DMA_DEV_TO_MEM) {
> >  		sdmac->per_address = dmaengine_cfg->src_addr;
> >  		sdmac->watermark_level = dmaengine_cfg->src_maxburst * @@
> -1738,6
> > +1749,8 @@ static void sdma_load_firmware(const struct firmware *fw,
> > void *context)
> >
> >  	sdma_add_scripts(sdma, addr);
> >
> > +	sdma->fw_loaded = true;
> > +
> >  	dev_info(sdma->dev, "loaded firmware %d.%d\n",
> >  			header->version_major,
> >  			header->version_minor);
>