From 0ad7c00057dc1640647c1dc81ccbd009de17a767 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Tue, 26 Nov 2013 10:04:22 -0700 Subject: dma: add channel request API that supports deferred probe dma_request_slave_channel() simply returns NULL whenever DMA channel lookup fails. Lookup could fail for two distinct reasons: a) No DMA specification exists for the channel name. This includes situations where no DMA specifications exist at all, or other general lookup problems. b) A DMA specification does exist, yet the driver for that channel is not yet registered. Case (b) should trigger deferred probe in client drivers. However, since they have no way to differentiate the two situations, it cannot. Implement new function dma_request_slave_channel_reason(), which performs identically to dma_request_slave_channel(), except that it returns an error-pointer rather than NULL, which allows callers to detect when deferred probe should occur. Eventually, all drivers should be converted to this new API, the old API removed, and the new API renamed to the more desirable name. This patch doesn't convert the existing API and all drivers in one go, since some drivers call dma_request_slave_channel() then dma_request_channel() if that fails. That would require either modifying dma_request_channel() in the same way, or adding extra error-handling code to all affected drivers, and there are close to 100 drivers using the other API, rather than just the 15-20 or so that use dma_request_slave_channel(), which might be tenable in a single patch. acpi_dma_request_slave_chan_by_name() doesn't currently implement deferred probe. It should, but this will be addressed later. Acked-by: Dan Williams Signed-off-by: Stephen Warren Signed-off-by: Vinod Koul --- include/linux/dmaengine.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/linux/dmaengine.h') diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 41cf0c399288..ed92b30a02fd 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -22,6 +22,7 @@ #define LINUX_DMAENGINE_H #include +#include #include #include #include @@ -1040,6 +1041,8 @@ 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); +struct dma_chan *dma_request_slave_channel_reason(struct device *dev, + const char *name); struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name); void dma_release_channel(struct dma_chan *chan); #else @@ -1063,6 +1066,11 @@ static inline struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask, { return NULL; } +static inline struct dma_chan *dma_request_slave_channel_reason( + struct device *dev, const char *name) +{ + return ERR_PTR(-ENODEV); +} static inline struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name) { -- cgit v1.2.3 From 8010dad55a0ab0e829f3733854e5235eef4e2734 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Tue, 26 Nov 2013 12:40:51 -0700 Subject: dma: add dma_get_any_slave_channel(), for use in of_xlate() mmp_pdma.c implements a custom of_xlate() function that is 95% identical to what Tegra will need. Create a function to implement the common part, so everyone doesn't just cut/paste the implementation. Cc: Dan Williams Cc: Vinod Koul Cc: Lars-Peter Clausen Cc: dmaengine@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Stephen Warren Signed-off-by: Vinod Koul --- include/linux/dmaengine.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/dmaengine.h') diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 41cf0c399288..09ef23ee8bce 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -1079,6 +1079,7 @@ int dma_async_device_register(struct dma_device *device); void dma_async_device_unregister(struct dma_device *device); 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); struct dma_chan *net_dma_find_channel(void); #define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y) #define dma_request_slave_channel_compat(mask, x, y, dev, name) \ -- cgit v1.2.3 From 397321f45d31159c84982978106f3165be44bc2b Mon Sep 17 00:00:00 2001 From: Alexander Popov Date: Mon, 16 Dec 2013 12:12:17 +0400 Subject: dmaengine: fix incorrect kernel-doc comment for struct dma_slave_config The 'direction' member of 'struct dma_slave_config' is of data type 'enum dma_transfer_direction', so update the kernel-doc comment for 'struct dma_slave_config' to refer to appropriate values. Signed-off-by: Alexander Popov Signed-off-by: Vinod Koul --- include/linux/dmaengine.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include/linux/dmaengine.h') diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 41cf0c399288..bd6b88222ced 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -305,9 +305,8 @@ enum dma_slave_buswidth { /** * struct dma_slave_config - dma slave channel runtime config * @direction: whether the data shall go in or out on this slave - * channel, right now. DMA_TO_DEVICE and DMA_FROM_DEVICE are - * legal values, DMA_BIDIRECTIONAL is not acceptable since we - * need to differentiate source and target addresses. + * channel, right now. DMA_MEM_TO_DEV and DMA_DEV_TO_MEM are + * legal values. * @src_addr: this is the physical address where DMA slave data * should be read (RX), if the source is memory this argument is * ignored. -- cgit v1.2.3 From 507205632dd12636cfe4af4322dace263dca0c21 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Sat, 11 Jan 2014 14:02:16 +0100 Subject: dma: Indicate residue granularity in dma_slave_caps This patch adds a new field to the dma_slave_caps struct which indicates the granularity with which the driver is able to update the residue field of the dma_tx_state struct. Making this information available to dmaengine users allows them to make better decisions on how to operate. E.g. for audio certain features like wakeup less operation or timer based scheduling only make sense and work correctly if the reported residue is fine-grained enough. Right now four different levels of granularity are supported: * DESCRIPTOR: The DMA channel is only able to tell whether a descriptor has been completed or not, which means residue reporting is not supported by this channel. The residue field of the dma_tx_state field will always be 0. * SEGMENT: The DMA channel updates the residue field after each successfully completed segment of the transfer (For cyclic transfers this is after each period). This is typically implemented by having the hardware generate an interrupt after each transferred segment and then the drivers updates the outstanding residue by the size of the segment. Another possibility is if the hardware supports SG and the segment descriptor has a field which gets set after the segment has been completed. The driver then counts the number of segments without the flag set to compute the residue. * BURST: The DMA channel updates the residue field after each transferred burst. This is typically only supported if the hardware has a progress register of some sort (E.g. a register with the current read/write address or a register with the amount of bursts/beats/bytes that have been transferred or still need to be transferred). Signed-off-by: Lars-Peter Clausen Acked-by: Vinod Koul Signed-off-by: Mark Brown --- include/linux/dmaengine.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include/linux/dmaengine.h') diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index ed92b30a02fd..ba5f96db0754 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -364,6 +364,32 @@ struct dma_slave_config { unsigned int slave_id; }; +/** + * enum dma_residue_granularity - Granularity of the reported transfer residue + * @DMA_RESIDUE_GRANULARITY_DESCRIPTOR: Residue reporting is not support. The + * DMA channel is only able to tell whether a descriptor has been completed or + * not, which means residue reporting is not supported by this channel. The + * residue field of the dma_tx_state field will always be 0. + * @DMA_RESIDUE_GRANULARITY_SEGMENT: Residue is updated after each successfully + * completed segment of the transfer (For cyclic transfers this is after each + * period). This is typically implemented by having the hardware generate an + * interrupt after each transferred segment and then the drivers updates the + * outstanding residue by the size of the segment. Another possibility is if + * the hardware supports scatter-gather and the segment descriptor has a field + * which gets set after the segment has been completed. The driver then counts + * the number of segments without the flag set to compute the residue. + * @DMA_RESIDUE_GRANULARITY_BURST: Residue is updated after each transferred + * burst. This is typically only supported if the hardware has a progress + * register of some sort (E.g. a register with the current read/write address + * or a register with the amount of bursts/beats/bytes that have been + * transferred or still need to be transferred). + */ +enum dma_residue_granularity { + DMA_RESIDUE_GRANULARITY_DESCRIPTOR = 0, + DMA_RESIDUE_GRANULARITY_SEGMENT = 1, + DMA_RESIDUE_GRANULARITY_BURST = 2, +}; + /* struct dma_slave_caps - expose capabilities of a slave channel only * * @src_addr_widths: bit mask of src addr widths the channel supports @@ -374,6 +400,7 @@ struct dma_slave_config { * should be checked by controller as well * @cmd_pause: true, if pause and thereby resume is supported * @cmd_terminate: true, if terminate cmd is supported + * @residue_granularity: granularity of the reported transfer residue */ struct dma_slave_caps { u32 src_addr_widths; @@ -381,6 +408,7 @@ struct dma_slave_caps { u32 directions; bool cmd_pause; bool cmd_terminate; + enum dma_residue_granularity residue_granularity; }; static inline const char *dma_chan_name(struct dma_chan *chan) -- cgit v1.2.3 From 868d2ee252918e7640df80156df9e1299f8118f5 Mon Sep 17 00:00:00 2001 From: Vinod Koul Date: Wed, 18 Dec 2013 21:39:39 +0530 Subject: dmaengine: fix kernel-doc style typos for few comments Signed-off-by: Vinod Koul --- include/linux/dmaengine.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include/linux/dmaengine.h') diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index fa6b4285d8d2..188108c36313 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -257,7 +257,7 @@ struct dma_chan_percpu { * @dev: class device for sysfs * @device_node: used to add this to the device chan list * @local: per-cpu pointer to a struct dma_chan_percpu - * @client-count: how many clients are using this channel + * @client_count: how many clients are using this channel * @table_count: number of appearances in the mem-to-mem allocation table * @private: private data for certain client-channel associations */ @@ -279,10 +279,10 @@ struct dma_chan { /** * struct dma_chan_dev - relate sysfs device node to backing channel device - * @chan - driver channel device - * @device - sysfs device - * @dev_id - parent dma_device dev_id - * @idr_ref - reference count to gate release of dma_device dev_id + * @chan: driver channel device + * @device: sysfs device + * @dev_id: parent dma_device dev_id + * @idr_ref: reference count to gate release of dma_device dev_id */ struct dma_chan_dev { struct dma_chan *chan; -- cgit v1.2.3