From 1099dc79245719c046e632212ec09d6ec1154ef5 Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Tue, 8 Jul 2008 11:58:05 -0700 Subject: dmaengine: Couple DMA channels to their physical DMA device Set the 'parent' field of channel class devices to point to the physical DMA device initialized by the DMA engine driver. This allows drivers to use chan->dev.parent for syncing DMA buffers and adds a 'device' symlink to the real device in /sys/class/dma/dmaXchanY. Signed-off-by: Haavard Skinnemoen Signed-off-by: Dan Williams --- drivers/dma/dmaengine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/dma/dmaengine.c') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 97b329e76798..99c22b42bada 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -378,7 +378,7 @@ int dma_async_device_register(struct dma_device *device) chan->chan_id = chancnt++; chan->dev.class = &dma_devclass; - chan->dev.parent = NULL; + chan->dev.parent = device->dev; snprintf(chan->dev.bus_id, BUS_ID_SIZE, "dma%dchan%d", device->dev_id, chan->chan_id); -- cgit v1.2.3 From 7cc5bf9a3a84e5a02e23e5739fb894790b37c101 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 8 Jul 2008 11:58:21 -0700 Subject: dmaengine: track the number of clients using a channel Haavard's dma-slave interface would like to test for exclusive access to a channel. The standard channel refcounting is not sufficient in that it tracks more than just client references, it is also inaccurate as reference counts are percpu until the channel is removed. This change also enables a future fix to deallocate resources when a client declines to use a capable channel. Acked-by: Haavard Skinnemoen Signed-off-by: Dan Williams --- drivers/dma/dmaengine.c | 14 ++++++++++---- include/linux/dmaengine.h | 2 ++ 2 files changed, 12 insertions(+), 4 deletions(-) (limited to 'drivers/dma/dmaengine.c') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 99c22b42bada..10de69eb1a3e 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -183,9 +183,10 @@ static void dma_client_chan_alloc(struct dma_client *client) /* we are done once this client rejects * an available resource */ - if (ack == DMA_ACK) + if (ack == DMA_ACK) { dma_chan_get(chan); - else if (ack == DMA_NAK) + chan->client_count++; + } else if (ack == DMA_NAK) return; } } @@ -272,8 +273,10 @@ static void dma_clients_notify_removed(struct dma_chan *chan) /* client was holding resources for this channel so * free it */ - if (ack == DMA_ACK) + if (ack == DMA_ACK) { dma_chan_put(chan); + chan->client_count--; + } } mutex_unlock(&dma_list_mutex); @@ -313,8 +316,10 @@ void dma_async_client_unregister(struct dma_client *client) ack = client->event_callback(client, chan, DMA_RESOURCE_REMOVED); - if (ack == DMA_ACK) + if (ack == DMA_ACK) { dma_chan_put(chan); + chan->client_count--; + } } list_del(&client->global_node); @@ -394,6 +399,7 @@ int dma_async_device_register(struct dma_device *device) kref_get(&device->refcount); kref_get(&device->refcount); kref_init(&chan->refcount); + chan->client_count = 0; chan->slow_ref = 0; INIT_RCU_HEAD(&chan->rcu); } diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index d08a5c5eb928..6432b8343220 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -139,6 +139,7 @@ struct dma_chan_percpu { * @rcu: the DMA channel's RCU head * @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 */ struct dma_chan { struct dma_device *device; @@ -154,6 +155,7 @@ struct dma_chan { struct list_head device_node; struct dma_chan_percpu *local; + int client_count; }; #define to_dma_chan(p) container_of(p, struct dma_chan, dev) -- cgit v1.2.3 From 848c536a37b8db4e461f14ca15fe29850151c822 Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Tue, 8 Jul 2008 11:58:58 -0700 Subject: dmaengine: Add dma_client parameter to device_alloc_chan_resources A DMA controller capable of doing slave transfers may need to know a few things about the slave when preparing the channel. We don't want to add this information to struct dma_channel since the channel hasn't yet been bound to a client at this point. Instead, pass a reference to the client requesting the channel to the driver's device_alloc_chan_resources hook so that it can pick the necessary information from the dma_client struct by itself. [dan.j.williams@intel.com: fixed up fsldma and mv_xor] Acked-by: Maciej Sosnowski Signed-off-by: Haavard Skinnemoen Signed-off-by: Dan Williams --- drivers/dma/dmaengine.c | 3 ++- drivers/dma/fsldma.c | 7 ++++--- drivers/dma/ioat_dma.c | 5 +++-- drivers/dma/iop-adma.c | 7 ++++--- drivers/dma/mv_xor.c | 7 ++++--- include/linux/dmaengine.h | 3 ++- 6 files changed, 19 insertions(+), 13 deletions(-) (limited to 'drivers/dma/dmaengine.c') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 10de69eb1a3e..7344f5dbd501 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -174,7 +174,8 @@ static void dma_client_chan_alloc(struct dma_client *client) if (!dma_chan_satisfies_mask(chan, client->cap_mask)) continue; - desc = chan->device->device_alloc_chan_resources(chan); + desc = chan->device->device_alloc_chan_resources( + chan, client); if (desc >= 0) { ack = client->event_callback(client, chan, diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c index 724f6fdd0af6..c0059ca58340 100644 --- a/drivers/dma/fsldma.c +++ b/drivers/dma/fsldma.c @@ -366,7 +366,8 @@ static struct fsl_desc_sw *fsl_dma_alloc_descriptor( * * Return - The number of descriptors allocated. */ -static int fsl_dma_alloc_chan_resources(struct dma_chan *chan) +static int fsl_dma_alloc_chan_resources(struct dma_chan *chan, + struct dma_client *client) { struct fsl_dma_chan *fsl_chan = to_fsl_chan(chan); LIST_HEAD(tmp_list); @@ -819,7 +820,7 @@ static int fsl_dma_self_test(struct fsl_dma_chan *fsl_chan) chan = &fsl_chan->common; - if (fsl_dma_alloc_chan_resources(chan) < 1) { + if (fsl_dma_alloc_chan_resources(chan, NULL) < 1) { dev_err(fsl_chan->dev, "selftest: Cannot alloc resources for DMA\n"); err = -ENODEV; @@ -847,7 +848,7 @@ static int fsl_dma_self_test(struct fsl_dma_chan *fsl_chan) /* Test free and re-alloc channel resources */ fsl_dma_free_chan_resources(chan); - if (fsl_dma_alloc_chan_resources(chan) < 1) { + if (fsl_dma_alloc_chan_resources(chan, NULL) < 1) { dev_err(fsl_chan->dev, "selftest: Cannot alloc resources for DMA\n"); err = -ENODEV; diff --git a/drivers/dma/ioat_dma.c b/drivers/dma/ioat_dma.c index 318e8a22d814..90e5b0a28cbf 100644 --- a/drivers/dma/ioat_dma.c +++ b/drivers/dma/ioat_dma.c @@ -452,7 +452,8 @@ static void ioat2_dma_massage_chan_desc(struct ioat_dma_chan *ioat_chan) * ioat_dma_alloc_chan_resources - returns the number of allocated descriptors * @chan: the channel to be filled out */ -static int ioat_dma_alloc_chan_resources(struct dma_chan *chan) +static int ioat_dma_alloc_chan_resources(struct dma_chan *chan, + struct dma_client *client) { struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan); struct ioat_desc_sw *desc; @@ -1049,7 +1050,7 @@ static int ioat_dma_self_test(struct ioatdma_device *device) dma_chan = container_of(device->common.channels.next, struct dma_chan, device_node); - if (device->common.device_alloc_chan_resources(dma_chan) < 1) { + if (device->common.device_alloc_chan_resources(dma_chan, NULL) < 1) { dev_err(&device->pdev->dev, "selftest cannot allocate chan resource\n"); err = -ENODEV; diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c index 4e6b052c0654..b57564dd0232 100644 --- a/drivers/dma/iop-adma.c +++ b/drivers/dma/iop-adma.c @@ -444,7 +444,8 @@ static void iop_chan_start_null_memcpy(struct iop_adma_chan *iop_chan); static void iop_chan_start_null_xor(struct iop_adma_chan *iop_chan); /* returns the number of allocated descriptors */ -static int iop_adma_alloc_chan_resources(struct dma_chan *chan) +static int iop_adma_alloc_chan_resources(struct dma_chan *chan, + struct dma_client *client) { char *hw_desc; int idx; @@ -838,7 +839,7 @@ static int __devinit iop_adma_memcpy_self_test(struct iop_adma_device *device) dma_chan = container_of(device->common.channels.next, struct dma_chan, device_node); - if (iop_adma_alloc_chan_resources(dma_chan) < 1) { + if (iop_adma_alloc_chan_resources(dma_chan, NULL) < 1) { err = -ENODEV; goto out; } @@ -936,7 +937,7 @@ iop_adma_xor_zero_sum_self_test(struct iop_adma_device *device) dma_chan = container_of(device->common.channels.next, struct dma_chan, device_node); - if (iop_adma_alloc_chan_resources(dma_chan) < 1) { + if (iop_adma_alloc_chan_resources(dma_chan, NULL) < 1) { err = -ENODEV; goto out; } diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c index f0c123ce8ae0..8239cfdbc2e6 100644 --- a/drivers/dma/mv_xor.c +++ b/drivers/dma/mv_xor.c @@ -588,7 +588,8 @@ submit_done: } /* returns the number of allocated descriptors */ -static int mv_xor_alloc_chan_resources(struct dma_chan *chan) +static int mv_xor_alloc_chan_resources(struct dma_chan *chan, + struct dma_client *client) { char *hw_desc; int idx; @@ -938,7 +939,7 @@ static int __devinit mv_xor_memcpy_self_test(struct mv_xor_device *device) dma_chan = container_of(device->common.channels.next, struct dma_chan, device_node); - if (mv_xor_alloc_chan_resources(dma_chan) < 1) { + if (mv_xor_alloc_chan_resources(dma_chan, NULL) < 1) { err = -ENODEV; goto out; } @@ -1033,7 +1034,7 @@ mv_xor_xor_self_test(struct mv_xor_device *device) dma_chan = container_of(device->common.channels.next, struct dma_chan, device_node); - if (mv_xor_alloc_chan_resources(dma_chan) < 1) { + if (mv_xor_alloc_chan_resources(dma_chan, NULL) < 1) { err = -ENODEV; goto out; } diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 6432b8343220..ba89b0f5056e 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -281,7 +281,8 @@ struct dma_device { int dev_id; struct device *dev; - int (*device_alloc_chan_resources)(struct dma_chan *chan); + int (*device_alloc_chan_resources)(struct dma_chan *chan, + struct dma_client *client); void (*device_free_chan_resources)(struct dma_chan *chan); struct dma_async_tx_descriptor *(*device_prep_dma_memcpy)( -- cgit v1.2.3 From dc0ee6435cb92ccc81b14ff28d163fecc5a7f120 Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Tue, 8 Jul 2008 11:59:35 -0700 Subject: dmaengine: Add slave DMA interface This patch adds the necessary interfaces to the DMA Engine framework to use functionality found on most embedded DMA controllers: DMA from and to I/O registers with hardware handshaking. In this context, hardware hanshaking means that the peripheral that owns the I/O registers in question is able to tell the DMA controller when more data is available for reading, or when there is room for more data to be written. This usually happens internally on the chip, but these signals may also be exported outside the chip for things like IDE DMA, etc. A new struct dma_slave is introduced. This contains information that the DMA engine driver needs to set up slave transfers to and from a slave device. Most engines supporting DMA slave transfers will want to extend this structure with controller-specific parameters. This additional information is usually passed from the platform/board code through the client driver. A "slave" pointer is added to the dma_client struct. This must point to a valid dma_slave structure iff the DMA_SLAVE capability is requested. The DMA engine driver may use this information in its device_alloc_chan_resources hook to configure the DMA controller for slave transfers from and to the given slave device. A new operation for preparing slave DMA transfers is added to struct dma_device. This takes a scatterlist and returns a single descriptor representing the whole transfer. Another new operation for terminating all pending transfers is added as well. The latter is needed because there may be errors outside the scope of the DMA Engine framework that may require DMA operations to be terminated prematurely. DMA Engine drivers may extend the dma_device, dma_chan and/or dma_slave_descriptor structures to allow controller-specific operations. The client driver can detect such extensions by looking at the DMA Engine's struct device, or it can request a specific DMA Engine device by setting the dma_dev field in struct dma_slave. dmaslave interface changes since v4: * Fix checkpatch errors * Fix changelog (there are no slave descriptors anymore) dmaslave interface changes since v3: * Use dma_data_direction instead of a new enum * Submit slave transfers as scatterlists * Remove the DMA slave descriptor struct dmaslave interface changes since v2: * Add a dma_dev field to struct dma_slave. If set, the client can only be bound to the DMA controller that corresponds to this device. This allows controller-specific extensions of the dma_slave structure; if the device matches, the controller may safely assume its extensions are present. * Move reg_width into struct dma_slave as there are currently no users that need to be able to set the width on a per-transfer basis. dmaslave interface changes since v1: * Drop the set_direction and set_width descriptor hooks. Pass the direction and width to the prep function instead. * Declare a dma_slave struct with fixed information about a slave, i.e. register addresses, handshake interfaces and such. * Add pointer to a dma_slave struct to dma_client. Can be NULL if the DMA_SLAVE capability isn't requested. * Drop the set_slave device hook since the alloc_chan_resources hook now has enough information to set up the channel for slave transfers. Acked-by: Maciej Sosnowski Signed-off-by: Haavard Skinnemoen Signed-off-by: Dan Williams --- drivers/dma/dmaengine.c | 16 ++++++++++++++- include/linux/dmaengine.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 66 insertions(+), 2 deletions(-) (limited to 'drivers/dma/dmaengine.c') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 7344f5dbd501..dc003a3a787d 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -169,7 +169,12 @@ static void dma_client_chan_alloc(struct dma_client *client) enum dma_state_client ack; /* Find a channel */ - list_for_each_entry(device, &dma_device_list, global_node) + list_for_each_entry(device, &dma_device_list, global_node) { + /* Does the client require a specific DMA controller? */ + if (client->slave && client->slave->dma_dev + && client->slave->dma_dev != device->dev) + continue; + list_for_each_entry(chan, &device->channels, device_node) { if (!dma_chan_satisfies_mask(chan, client->cap_mask)) continue; @@ -191,6 +196,7 @@ static void dma_client_chan_alloc(struct dma_client *client) return; } } + } } enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie) @@ -289,6 +295,10 @@ static void dma_clients_notify_removed(struct dma_chan *chan) */ void dma_async_client_register(struct dma_client *client) { + /* validate client data */ + BUG_ON(dma_has_cap(DMA_SLAVE, client->cap_mask) && + !client->slave); + mutex_lock(&dma_list_mutex); list_add_tail(&client->global_node, &dma_client_list); mutex_unlock(&dma_list_mutex); @@ -365,6 +375,10 @@ int dma_async_device_register(struct dma_device *device) !device->device_prep_dma_memset); BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) && !device->device_prep_dma_interrupt); + BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) && + !device->device_prep_slave_sg); + BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) && + !device->device_terminate_all); BUG_ON(!device->device_alloc_chan_resources); BUG_ON(!device->device_free_chan_resources); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index b058d6360383..9b91d341e1fa 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -89,10 +89,23 @@ enum dma_transaction_type { DMA_MEMSET, DMA_MEMCPY_CRC32C, DMA_INTERRUPT, + DMA_SLAVE, }; /* last transaction type for creation of the capabilities mask */ -#define DMA_TX_TYPE_END (DMA_INTERRUPT + 1) +#define DMA_TX_TYPE_END (DMA_SLAVE + 1) + +/** + * enum dma_slave_width - DMA slave register access width. + * @DMA_SLAVE_WIDTH_8BIT: Do 8-bit slave register accesses + * @DMA_SLAVE_WIDTH_16BIT: Do 16-bit slave register accesses + * @DMA_SLAVE_WIDTH_32BIT: Do 32-bit slave register accesses + */ +enum dma_slave_width { + DMA_SLAVE_WIDTH_8BIT, + DMA_SLAVE_WIDTH_16BIT, + DMA_SLAVE_WIDTH_32BIT, +}; /** * enum dma_ctrl_flags - DMA flags to augment operation preparation, @@ -118,6 +131,32 @@ enum dma_ctrl_flags { */ typedef struct { DECLARE_BITMAP(bits, DMA_TX_TYPE_END); } dma_cap_mask_t; +/** + * struct dma_slave - Information about a DMA slave + * @dev: device acting as DMA slave + * @dma_dev: required DMA master device. If non-NULL, the client can not be + * bound to other masters than this. + * @tx_reg: physical address of data register used for + * memory-to-peripheral transfers + * @rx_reg: physical address of data register used for + * peripheral-to-memory transfers + * @reg_width: peripheral register width + * + * If dma_dev is non-NULL, the client can not be bound to other DMA + * masters than the one corresponding to this device. The DMA master + * driver may use this to determine if there is controller-specific + * data wrapped around this struct. Drivers of platform code that sets + * the dma_dev field must therefore make sure to use an appropriate + * controller-specific dma slave structure wrapping this struct. + */ +struct dma_slave { + struct device *dev; + struct device *dma_dev; + dma_addr_t tx_reg; + dma_addr_t rx_reg; + enum dma_slave_width reg_width; +}; + /** * struct dma_chan_percpu - the per-CPU part of struct dma_chan * @refcount: local_t used for open-coded "bigref" counting @@ -208,11 +247,14 @@ typedef enum dma_state_client (*dma_event_callback) (struct dma_client *client, * @event_callback: func ptr to call when something happens * @cap_mask: only return channels that satisfy the requested capabilities * a value of zero corresponds to any capability + * @slave: data for preparing slave transfer. Must be non-NULL iff the + * DMA_SLAVE capability is requested. * @global_node: list_head for global dma_client_list */ struct dma_client { dma_event_callback event_callback; dma_cap_mask_t cap_mask; + struct dma_slave *slave; struct list_head global_node; }; @@ -269,6 +311,8 @@ struct dma_async_tx_descriptor { * @device_prep_dma_zero_sum: prepares a zero_sum operation * @device_prep_dma_memset: prepares a memset operation * @device_prep_dma_interrupt: prepares an end of chain interrupt operation + * @device_prep_slave_sg: prepares a slave dma operation + * @device_terminate_all: terminate all pending operations * @device_issue_pending: push pending transactions to hardware */ struct dma_device { @@ -304,6 +348,12 @@ struct dma_device { struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)( struct dma_chan *chan, unsigned long flags); + struct dma_async_tx_descriptor *(*device_prep_slave_sg)( + struct dma_chan *chan, struct scatterlist *sgl, + unsigned int sg_len, enum dma_data_direction direction, + unsigned long flags); + void (*device_terminate_all)(struct dma_chan *chan); + enum dma_status (*device_is_tx_complete)(struct dma_chan *chan, dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used); -- cgit v1.2.3