From: Vinod Koul <vkoul@kernel.org>
To: Lubomir Rintel <lkundrak@v3.sk>
Cc: Dan Williams <dan.j.williams@intel.com>,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/7] dmaengine: mmp_tdma: Validate the transfer direction
Date: Thu, 23 Apr 2020 12:36:57 +0530 [thread overview]
Message-ID: <20200423070657.GW72691@vkoul-mobl> (raw)
In-Reply-To: <20200419164912.670973-4-lkundrak@v3.sk>
On 19-04-20, 18:49, Lubomir Rintel wrote:
> We only support DMA_DEV_TO_MEM and DMA_MEM_TO_DEV. Let's not do
> undefined things with other values and reject them.
>
> Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
> ---
> drivers/dma/mmp_tdma.c | 37 ++++++++++++++++++++++++++++---------
> 1 file changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/mmp_tdma.c b/drivers/dma/mmp_tdma.c
> index d559bb4d6a31d..d574641791598 100644
> --- a/drivers/dma/mmp_tdma.c
> +++ b/drivers/dma/mmp_tdma.c
> @@ -207,10 +207,17 @@ static int mmp_tdma_config_chan(struct dma_chan *chan)
>
> mmp_tdma_disable_chan(chan);
>
> - if (tdmac->dir == DMA_MEM_TO_DEV)
> - tdcr = TDCR_DSTDIR_ADDR_HOLD | TDCR_SRCDIR_ADDR_INC;
> - else if (tdmac->dir == DMA_DEV_TO_MEM)
> + switch (tdmac->dir) {
> + case DMA_DEV_TO_MEM:
> tdcr = TDCR_SRCDIR_ADDR_HOLD | TDCR_DSTDIR_ADDR_INC;
> + break;
> + case DMA_MEM_TO_DEV:
> + tdcr = TDCR_DSTDIR_ADDR_HOLD | TDCR_SRCDIR_ADDR_INC;
> + break;
> + default:
> + dev_err(tdmac->dev, "invalid transfer direction\n");
> + return -EINVAL;
> + }
You can use macros is_slave_direction() to validate
> if (tdmac->type == MMP_AUD_TDMA) {
> tdcr |= TDCR_PACKMOD;
> @@ -455,12 +462,18 @@ static struct dma_async_tx_descriptor *mmp_tdma_prep_dma_cyclic(
> desc->nxt_desc = tdmac->desc_arr_phys +
> sizeof(*desc) * (i + 1);
>
It would make more sense to use is_slave_direction() and reject up early
in the function and proceed only when good :)
> - if (direction == DMA_MEM_TO_DEV) {
> - desc->src_addr = dma_addr;
> - desc->dst_addr = tdmac->dev_addr;
> - } else {
> + switch (direction) {
> + case DMA_DEV_TO_MEM:
> desc->src_addr = tdmac->dev_addr;
> desc->dst_addr = dma_addr;
> + break;
> + case DMA_MEM_TO_DEV:
> + desc->src_addr = dma_addr;
> + desc->dst_addr = tdmac->dev_addr;
> + break;
> + default:
> + dev_err(tdmac->dev, "invalid transfer direction\n");
> + goto err_out;
> }
> desc->byte_cnt = period_len;
> dma_addr += period_len;
> @@ -510,14 +523,20 @@ static int mmp_tdma_config_write(struct dma_chan *chan,
> {
> struct mmp_tdma_chan *tdmac = to_mmp_tdma_chan(chan);
>
> - if (dir == DMA_DEV_TO_MEM) {
> + switch (dir) {
> + case DMA_DEV_TO_MEM:
> tdmac->dev_addr = dmaengine_cfg->src_addr;
> tdmac->burst_sz = dmaengine_cfg->src_maxburst;
> tdmac->buswidth = dmaengine_cfg->src_addr_width;
> - } else {
> + break;
> + case DMA_MEM_TO_DEV:
> tdmac->dev_addr = dmaengine_cfg->dst_addr;
> tdmac->burst_sz = dmaengine_cfg->dst_maxburst;
> tdmac->buswidth = dmaengine_cfg->dst_addr_width;
> + break;
> + default:
> + dev_err(tdmac->dev, "invalid transfer direction\n");
> + return -EINVAL;
is this required, if you have checked in all _prep() fns then you are
guaranteed that this will never hit, right?
--
~Vinod
next prev parent reply other threads:[~2020-04-23 7:07 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-19 16:49 [PATCH 0/7] dmaengine: mmp_tdma: Make the driver actually work Lubomir Rintel
2020-04-19 16:49 ` [PATCH 1/7] dmaengine: mmp_tdma: Do not ignore slave config validation errors Lubomir Rintel
2020-04-23 7:13 ` Vinod Koul
2020-04-19 16:49 ` [PATCH 2/7] dmaengine: mmp_tdma: Drop "mmp_tdma: from error messages Lubomir Rintel
2020-04-23 7:13 ` Vinod Koul
2020-04-19 16:49 ` [PATCH 3/7] dmaengine: mmp_tdma: Validate the transfer direction Lubomir Rintel
2020-04-23 7:06 ` Vinod Koul [this message]
2020-04-19 16:49 ` [PATCH 4/7] dmaengine: mmp_tdma: Reset channel error on release Lubomir Rintel
2020-04-23 7:14 ` Vinod Koul
2020-04-19 16:49 ` [PATCH 5/7] dmaengine: mmp_tdma: Log an error if channel is in wrong state Lubomir Rintel
2020-04-23 7:15 ` Vinod Koul
2020-04-19 16:49 ` [PATCH 6/7] dmaengine: mmp_tdma: Fill in slave capabilities Lubomir Rintel
2020-04-23 7:16 ` Vinod Koul
2020-04-19 16:49 ` [PATCH 7/7] dmaengine: mmp_tdma: Remove the MMP_SRAM dependency Lubomir Rintel
2020-04-23 7:16 ` Vinod Koul
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