Hi,
On 07/05/2019 9.09, Baolin Wang wrote:
> When user try to request one DMA channel by __dma_request_channel(), it won't
> validate if it is the correct DMA device to request, that will lead each DMA
> engine driver to validate the correct device node in their filter function
> if it is necessary.
>
> Thus we can add the matching device node validation in the DMA engine core,
> to remove all of device node validation in the drivers.
I have picked this patch to my TI UDMA series and with
__dma_request_channel() it works as expected - picking the channel from
the correct DMA device.
Tested-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
>
> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
> ---
> drivers/dma/dmaengine.c | 10 ++++++++--
> drivers/dma/of-dma.c | 4 ++--
> include/linux/dmaengine.h | 12 ++++++++----
> 3 files changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 3a11b10..610080c 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -641,11 +641,13 @@ struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
> * @mask: capabilities that the channel must satisfy
> * @fn: optional callback to disposition available channels
> * @fn_param: opaque parameter to pass to dma_filter_fn
> + * @np: device node to look for DMA channels
> *
> * Returns pointer to appropriate DMA channel on success or NULL.
> */
> struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
> - dma_filter_fn fn, void *fn_param)
> + dma_filter_fn fn, void *fn_param,
> + struct device_node *np)
> {
> struct dma_device *device, *_d;
> struct dma_chan *chan = NULL;
> @@ -653,6 +655,10 @@ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
> /* Find a channel */
> mutex_lock(&dma_list_mutex);
> list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
> + /* Finds a DMA controller with matching device node */
> + if (np && device->dev->of_node && np != device->dev->of_node)
> + continue;
> +
> chan = find_candidate(device, mask, fn, fn_param);
> if (!IS_ERR(chan))
> break;
> @@ -769,7 +775,7 @@ struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
> if (!mask)
> return ERR_PTR(-ENODEV);
>
> - chan = __dma_request_channel(mask, NULL, NULL);
> + chan = __dma_request_channel(mask, NULL, NULL, NULL);
> if (!chan) {
> mutex_lock(&dma_list_mutex);
> if (list_empty(&dma_device_list))
> diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
> index 91fd395..6b43d04 100644
> --- a/drivers/dma/of-dma.c
> +++ b/drivers/dma/of-dma.c
> @@ -316,8 +316,8 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
> if (count != 1)
> return NULL;
>
> - return dma_request_channel(info->dma_cap, info->filter_fn,
> - &dma_spec->args[0]);
> + return __dma_request_channel(&info->dma_cap, info->filter_fn,
> + &dma_spec->args[0], dma_spec->np);
> }
> EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
>
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index d49ec5c..504085b 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -1314,7 +1314,8 @@ static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
> enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
> void dma_issue_pending_all(void);
> struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
> - dma_filter_fn fn, void *fn_param);
> + dma_filter_fn fn, void *fn_param,
> + struct device_node *np);
> struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name);
>
> struct dma_chan *dma_request_chan(struct device *dev, const char *name);
> @@ -1339,7 +1340,9 @@ static inline void dma_issue_pending_all(void)
> {
> }
> static inline struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
> - dma_filter_fn fn, void *fn_param)
> + dma_filter_fn fn,
> + void *fn_param,
> + struct device_node *np)
> {
> return NULL;
> }
> @@ -1411,7 +1414,8 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
> void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
> struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
> struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);
> -#define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)
> +#define dma_request_channel(mask, x, y) \
> + __dma_request_channel(&(mask), x, y, NULL)
> #define dma_request_slave_channel_compat(mask, x, y, dev, name) \
> __dma_request_slave_channel_compat(&(mask), x, y, dev, name)
>
> @@ -1429,6 +1433,6 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
> if (!fn || !fn_param)
> return NULL;
>
> - return __dma_request_channel(mask, fn, fn_param);
> + return __dma_request_channel(mask, fn, fn_param, NULL);
> }
> #endif /* DMAENGINE_H */
>
- Péter
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