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dmaengine: core: Introduce new, universal API to request a channel
The two API function can cover most, if not all current APIs used to request a channel. With minimal effort dmaengine drivers, platforms and dmaengine user drivers can be converted to use the two function. struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask); To request any channel matching with the requested capabilities, can be used to request channel for memcpy, memset, xor, etc where no hardware synchronization is needed. struct dma_chan *dma_request_chan(struct device *dev, const char *name); To request a slave channel. The dma_request_chan() will try to find the channel via DT, ACPI or in case if the kernel booted in non DT/ACPI mode it will use a filter lookup table and retrieves the needed information from the dma_slave_map provided by the DMA drivers. This legacy mode needs changes in platform code, in dmaengine drivers and finally the dmaengine user drivers can be converted: For each dmaengine driver an array of DMA device, slave and the parameter for the filter function needs to be added: static const struct dma_slave_map da830_edma_map[] = { { "davinci-mcasp.0", "rx", EDMA_FILTER_PARAM(0, 0) }, { "davinci-mcasp.0", "tx", EDMA_FILTER_PARAM(0, 1) }, { "davinci-mcasp.1", "rx", EDMA_FILTER_PARAM(0, 2) }, { "davinci-mcasp.1", "tx", EDMA_FILTER_PARAM(0, 3) }, { "davinci-mcasp.2", "rx", EDMA_FILTER_PARAM(0, 4) }, { "davinci-mcasp.2", "tx", EDMA_FILTER_PARAM(0, 5) }, { "spi_davinci.0", "rx", EDMA_FILTER_PARAM(0, 14) }, { "spi_davinci.0", "tx", EDMA_FILTER_PARAM(0, 15) }, { "da830-mmc.0", "rx", EDMA_FILTER_PARAM(0, 16) }, { "da830-mmc.0", "tx", EDMA_FILTER_PARAM(0, 17) }, { "spi_davinci.1", "rx", EDMA_FILTER_PARAM(0, 18) }, { "spi_davinci.1", "tx", EDMA_FILTER_PARAM(0, 19) }, }; This information is going to be needed by the dmaengine driver, so modification to the platform_data is needed, and the driver map should be added to the pdata of the DMA driver: da8xx_edma0_pdata.slave_map = da830_edma_map; da8xx_edma0_pdata.slavecnt = ARRAY_SIZE(da830_edma_map); The DMA driver then needs to configure the needed device -> filter_fn mapping before it registers with dma_async_device_register() : ecc->dma_slave.filter_map.map = info->slave_map; ecc->dma_slave.filter_map.mapcnt = info->slavecnt; ecc->dma_slave.filter_map.fn = edma_filter_fn; When neither DT or ACPI lookup is available the dma_request_chan() will try to match the requester's device name with the filter_map's list of device names, when a match found it will use the information from the dma_slave_map to get the channel with the dma_get_channel() internal function. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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3 changed files with 126 additions and 35 deletions
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@ -606,12 +606,39 @@ enum dmaengine_alignment {
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DMAENGINE_ALIGN_64_BYTES = 6,
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};
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/**
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* struct dma_slave_map - associates slave device and it's slave channel with
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* parameter to be used by a filter function
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* @devname: name of the device
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* @slave: slave channel name
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* @param: opaque parameter to pass to struct dma_filter.fn
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*/
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struct dma_slave_map {
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const char *devname;
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const char *slave;
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void *param;
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};
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/**
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* struct dma_filter - information for slave device/channel to filter_fn/param
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* mapping
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* @fn: filter function callback
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* @mapcnt: number of slave device/channel in the map
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* @map: array of channel to filter mapping data
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*/
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struct dma_filter {
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dma_filter_fn fn;
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int mapcnt;
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const struct dma_slave_map *map;
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};
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/**
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* struct dma_device - info on the entity supplying DMA services
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* @chancnt: how many DMA channels are supported
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* @privatecnt: how many DMA channels are requested by dma_request_channel
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* @channels: the list of struct dma_chan
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* @global_node: list_head for global dma_device_list
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* @filter: information for device/slave to filter function/param mapping
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* @cap_mask: one or more dma_capability flags
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* @max_xor: maximum number of xor sources, 0 if no capability
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* @max_pq: maximum number of PQ sources and PQ-continue capability
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@ -666,6 +693,7 @@ struct dma_device {
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unsigned int privatecnt;
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struct list_head channels;
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struct list_head global_node;
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struct dma_filter filter;
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dma_cap_mask_t cap_mask;
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unsigned short max_xor;
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unsigned short max_pq;
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@ -1140,9 +1168,11 @@ enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
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void dma_issue_pending_all(void);
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struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
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dma_filter_fn fn, void *fn_param);
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struct dma_chan *dma_request_slave_channel_reason(struct device *dev,
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const char *name);
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struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name);
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struct dma_chan *dma_request_chan(struct device *dev, const char *name);
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struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask);
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void dma_release_channel(struct dma_chan *chan);
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int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps);
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#else
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@ -1166,16 +1196,21 @@ static inline struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
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{
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return NULL;
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}
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static inline struct dma_chan *dma_request_slave_channel_reason(
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struct device *dev, const char *name)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline struct dma_chan *dma_request_slave_channel(struct device *dev,
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const char *name)
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{
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return NULL;
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}
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static inline struct dma_chan *dma_request_chan(struct device *dev,
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const char *name)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline struct dma_chan *dma_request_chan_by_mask(
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const dma_cap_mask_t *mask)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline void dma_release_channel(struct dma_chan *chan)
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{
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}
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@ -1186,6 +1221,8 @@ static inline int dma_get_slave_caps(struct dma_chan *chan,
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}
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#endif
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#define dma_request_slave_channel_reason(dev, name) dma_request_chan(dev, name)
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static inline int dmaengine_desc_set_reuse(struct dma_async_tx_descriptor *tx)
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{
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struct dma_slave_caps caps;
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