Now that the generic DMAEngine API has support for scatterlist to scatterlist copying, this implementation of the DMA_SLAVE API is no longer necessary.
In order to let device_control() continue to function, a stub device_prep_slave_sg() function is provided. This allows custom device configuration, such as enabling external control. Signed-off-by: Ira W. Snyder <[email protected]> --- arch/powerpc/include/asm/fsldma.h | 115 ++------------------ drivers/dma/fsldma.c | 219 +++++++------------------------------ 2 files changed, 48 insertions(+), 286 deletions(-) diff --git a/arch/powerpc/include/asm/fsldma.h b/arch/powerpc/include/asm/fsldma.h index debc5ed..dc0bd27 100644 --- a/arch/powerpc/include/asm/fsldma.h +++ b/arch/powerpc/include/asm/fsldma.h @@ -1,7 +1,7 @@ /* * Freescale MPC83XX / MPC85XX DMA Controller * - * Copyright (c) 2009 Ira W. Snyder <[email protected]> + * Copyright (c) 2009-2010 Ira W. Snyder <[email protected]> * * This file is licensed under the terms of the GNU General Public License * version 2. This program is licensed "as is" without any warranty of any @@ -11,127 +11,32 @@ #ifndef __ARCH_POWERPC_ASM_FSLDMA_H__ #define __ARCH_POWERPC_ASM_FSLDMA_H__ -#include <linux/slab.h> #include <linux/dmaengine.h> /* - * Definitions for the Freescale DMA controller's DMA_SLAVE implemention + * The Freescale DMA controller has several features that are not accomodated + * in the Linux DMAEngine API. Therefore, the generic structure is expanded + * to allow drivers to use these features. * - * The Freescale DMA_SLAVE implementation was designed to handle many-to-many - * transfers. An example usage would be an accelerated copy between two - * scatterlists. Another example use would be an accelerated copy from - * multiple non-contiguous device buffers into a single scatterlist. + * This structure should be passed into the DMAEngine routine device_control() + * as in this example: * - * A DMA_SLAVE transaction is defined by a struct fsl_dma_slave. This - * structure contains a list of hardware addresses that should be copied - * to/from the scatterlist passed into device_prep_slave_sg(). The structure - * also has some fields to enable hardware-specific features. + * chan->device->device_control(chan, DMA_SLAVE_CONFIG, (unsigned long)cfg); */ /** - * struct fsl_dma_hw_addr - * @entry: linked list entry - * @address: the hardware address - * @length: length to transfer - * - * Holds a single physical hardware address / length pair for use - * with the DMAEngine DMA_SLAVE API. - */ -struct fsl_dma_hw_addr { - struct list_head entry; - - dma_addr_t address; - size_t length; -}; - -/** * struct fsl_dma_slave - * @addresses: a linked list of struct fsl_dma_hw_addr structures + * @config: the standard Linux DMAEngine API DMA_SLAVE configuration * @request_count: value for DMA request count - * @src_loop_size: setup and enable constant source-address DMA transfers - * @dst_loop_size: setup and enable constant destination address DMA transfers * @external_start: enable externally started DMA transfers * @external_pause: enable externally paused DMA transfers - * - * Holds a list of address / length pairs for use with the DMAEngine - * DMA_SLAVE API implementation for the Freescale DMA controller. */ -struct fsl_dma_slave { +struct fsldma_slave_config { + struct dma_slave_config config; - /* List of hardware address/length pairs */ - struct list_head addresses; - - /* Support for extra controller features */ unsigned int request_count; - unsigned int src_loop_size; - unsigned int dst_loop_size; bool external_start; bool external_pause; }; -/** - * fsl_dma_slave_append - add an address/length pair to a struct fsl_dma_slave - * @slave: the &struct fsl_dma_slave to add to - * @address: the hardware address to add - * @length: the length of bytes to transfer from @address - * - * Add a hardware address/length pair to a struct fsl_dma_slave. Returns 0 on - * success, -ERRNO otherwise. - */ -static inline int fsl_dma_slave_append(struct fsl_dma_slave *slave, - dma_addr_t address, size_t length) -{ - struct fsl_dma_hw_addr *addr; - - addr = kzalloc(sizeof(*addr), GFP_ATOMIC); - if (!addr) - return -ENOMEM; - - INIT_LIST_HEAD(&addr->entry); - addr->address = address; - addr->length = length; - - list_add_tail(&addr->entry, &slave->addresses); - return 0; -} - -/** - * fsl_dma_slave_free - free a struct fsl_dma_slave - * @slave: the struct fsl_dma_slave to free - * - * Free a struct fsl_dma_slave and all associated address/length pairs - */ -static inline void fsl_dma_slave_free(struct fsl_dma_slave *slave) -{ - struct fsl_dma_hw_addr *addr, *tmp; - - if (slave) { - list_for_each_entry_safe(addr, tmp, &slave->addresses, entry) { - list_del(&addr->entry); - kfree(addr); - } - - kfree(slave); - } -} - -/** - * fsl_dma_slave_alloc - allocate a struct fsl_dma_slave - * @gfp: the flags to pass to kmalloc when allocating this structure - * - * Allocate a struct fsl_dma_slave for use by the DMA_SLAVE API. Returns a new - * struct fsl_dma_slave on success, or NULL on failure. - */ -static inline struct fsl_dma_slave *fsl_dma_slave_alloc(gfp_t gfp) -{ - struct fsl_dma_slave *slave; - - slave = kzalloc(sizeof(*slave), gfp); - if (!slave) - return NULL; - - INIT_LIST_HEAD(&slave->addresses); - return slave; -} - #endif /* __ARCH_POWERPC_ASM_FSLDMA_H__ */ diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c index 1ed29d1..d3ce25b 100644 --- a/drivers/dma/fsldma.c +++ b/drivers/dma/fsldma.c @@ -719,207 +719,64 @@ static struct dma_async_tx_descriptor *fsl_dma_prep_slave_sg( struct dma_chan *dchan, struct scatterlist *sgl, unsigned int sg_len, enum dma_data_direction direction, unsigned long flags) { - struct fsldma_chan *chan; - struct fsl_desc_sw *first = NULL, *prev = NULL, *new = NULL; - struct fsl_dma_slave *slave; - size_t copy; - - int i; - struct scatterlist *sg; - size_t sg_used; - size_t hw_used; - struct fsl_dma_hw_addr *hw; - dma_addr_t dma_dst, dma_src; - - if (!dchan) - return NULL; - - if (!dchan->private) - return NULL; - - chan = to_fsl_chan(dchan); - slave = dchan->private; - - if (list_empty(&slave->addresses)) - return NULL; - - hw = list_first_entry(&slave->addresses, struct fsl_dma_hw_addr, entry); - hw_used = 0; - /* - * Build the hardware transaction to copy from the scatterlist to - * the hardware, or from the hardware to the scatterlist - * - * If you are copying from the hardware to the scatterlist and it - * takes two hardware entries to fill an entire page, then both - * hardware entries will be coalesced into the same page + * This operation is not supported on the Freescale DMA controller * - * If you are copying from the scatterlist to the hardware and a - * single page can fill two hardware entries, then the data will - * be read out of the page into the first hardware entry, and so on + * However, we need to provide the function pointer to allow the + * device_control() method to work. */ - for_each_sg(sgl, sg, sg_len, i) { - sg_used = 0; - - /* Loop until the entire scatterlist entry is used */ - while (sg_used < sg_dma_len(sg)) { - - /* - * If we've used up the current hardware address/length - * pair, we need to load a new one - * - * This is done in a while loop so that descriptors with - * length == 0 will be skipped - */ - while (hw_used >= hw->length) { - - /* - * If the current hardware entry is the last - * entry in the list, we're finished - */ - if (list_is_last(&hw->entry, &slave->addresses)) - goto finished; - - /* Get the next hardware address/length pair */ - hw = list_entry(hw->entry.next, - struct fsl_dma_hw_addr, entry); - hw_used = 0; - } - - /* Allocate the link descriptor from DMA pool */ - new = fsl_dma_alloc_descriptor(chan); - if (!new) { - dev_err(chan->dev, "No free memory for " - "link descriptor\n"); - goto fail; - } -#ifdef FSL_DMA_LD_DEBUG - dev_dbg(chan->dev, "new link desc alloc %p\n", new); -#endif - - /* - * Calculate the maximum number of bytes to transfer, - * making sure it is less than the DMA controller limit - */ - copy = min_t(size_t, sg_dma_len(sg) - sg_used, - hw->length - hw_used); - copy = min_t(size_t, copy, FSL_DMA_BCR_MAX_CNT); - - /* - * DMA_FROM_DEVICE - * from the hardware to the scatterlist - * - * DMA_TO_DEVICE - * from the scatterlist to the hardware - */ - if (direction == DMA_FROM_DEVICE) { - dma_src = hw->address + hw_used; - dma_dst = sg_dma_address(sg) + sg_used; - } else { - dma_src = sg_dma_address(sg) + sg_used; - dma_dst = hw->address + hw_used; - } - - /* Fill in the descriptor */ - set_desc_cnt(chan, &new->hw, copy); - set_desc_src(chan, &new->hw, dma_src); - set_desc_dst(chan, &new->hw, dma_dst); - - /* - * If this is not the first descriptor, chain the - * current descriptor after the previous descriptor - */ - if (!first) { - first = new; - } else { - set_desc_next(chan, &prev->hw, - new->async_tx.phys); - } - - new->async_tx.cookie = 0; - async_tx_ack(&new->async_tx); - - prev = new; - sg_used += copy; - hw_used += copy; - - /* Insert the link descriptor into the LD ring */ - list_add_tail(&new->node, &first->tx_list); - } - } - -finished: - - /* All of the hardware address/length pairs had length == 0 */ - if (!first || !new) - return NULL; - - new->async_tx.flags = flags; - new->async_tx.cookie = -EBUSY; - - /* Set End-of-link to the last link descriptor of new list */ - set_ld_eol(chan, new); - - /* Enable extra controller features */ - if (chan->set_src_loop_size) - chan->set_src_loop_size(chan, slave->src_loop_size); - - if (chan->set_dst_loop_size) - chan->set_dst_loop_size(chan, slave->dst_loop_size); - - if (chan->toggle_ext_start) - chan->toggle_ext_start(chan, slave->external_start); - - if (chan->toggle_ext_pause) - chan->toggle_ext_pause(chan, slave->external_pause); - - if (chan->set_request_count) - chan->set_request_count(chan, slave->request_count); - - return &first->async_tx; - -fail: - /* If first was not set, then we failed to allocate the very first - * descriptor, and we're done */ - if (!first) - return NULL; - - /* - * First is set, so all of the descriptors we allocated have been added - * to first->tx_list, INCLUDING "first" itself. Therefore we - * must traverse the list backwards freeing each descriptor in turn - * - * We're re-using variables for the loop, oh well - */ - fsldma_free_desc_list_reverse(chan, &first->tx_list); return NULL; } static int fsl_dma_device_control(struct dma_chan *dchan, enum dma_ctrl_cmd cmd, unsigned long arg) { + struct fsldma_slave_config *cfg; struct fsldma_chan *chan; unsigned long flags; - /* Only supports DMA_TERMINATE_ALL */ - if (cmd != DMA_TERMINATE_ALL) - return -ENXIO; - if (!dchan) return -EINVAL; chan = to_fsl_chan(dchan); - /* Halt the DMA engine */ - dma_halt(chan); + switch (cmd) { + case DMA_TERMINATE_ALL: + /* Halt the DMA engine */ + dma_halt(chan); - spin_lock_irqsave(&chan->desc_lock, flags); + spin_lock_irqsave(&chan->desc_lock, flags); - /* Remove and free all of the descriptors in the LD queue */ - fsldma_free_desc_list(chan, &chan->ld_pending); - fsldma_free_desc_list(chan, &chan->ld_running); + /* Remove and free all of the descriptors in the LD queue */ + fsldma_free_desc_list(chan, &chan->ld_pending); + fsldma_free_desc_list(chan, &chan->ld_running); - spin_unlock_irqrestore(&chan->desc_lock, flags); + spin_unlock_irqrestore(&chan->desc_lock, flags); + return 0; + + case DMA_SLAVE_CONFIG: + + cfg = (struct fsldma_slave_config *)arg; + if (chan->set_request_count) + chan->set_request_count(chan, cfg->request_count); + + if (chan->toggle_ext_start) + chan->toggle_ext_start(chan, cfg->external_start); + + if (chan->toggle_ext_pause) + chan->toggle_ext_pause(chan, cfg->external_pause); + + /* + * TODO: add other features + * + * I'm not sure how to use the members dma_slave_config to + * control the src/dst address hold features. + */ + return 0; + + default: + return -ENXIO; + } return 0; } -- 1.7.1 _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
