Re: [PATCH 1/8] dmaengine: Add matching device node validation in __dma_request_channel()
From: Baolin Wang
Date: Mon May 20 2019 - 07:29:40 EST
On Tue, 7 May 2019 at 16:37, Peter Ujfalusi <peter.ujfalusi@xxxxxx> wrote:
>
> 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>
Thanks Peter.
>
> >
> > 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 */
> >
>
> - PÃter
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
--
Baolin Wang
Best Regards