diff options
| -rw-r--r-- | arch/powerpc/include/asm/fsldma.h | 136 | ||||
| -rw-r--r-- | drivers/dma/fsldma.c | 227 |
2 files changed, 363 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/fsldma.h b/arch/powerpc/include/asm/fsldma.h new file mode 100644 index 000000000000..a67aeed17d40 --- /dev/null +++ b/arch/powerpc/include/asm/fsldma.h @@ -0,0 +1,136 @@ +/* + * Freescale MPC83XX / MPC85XX DMA Controller + * + * Copyright (c) 2009 Ira W. Snyder <iws@ovro.caltech.edu> + * + * 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 + * kind, whether express or implied. + */ + +#ifndef __ARCH_POWERPC_ASM_FSLDMA_H__ +#define __ARCH_POWERPC_ASM_FSLDMA_H__ + +#include <linux/dmaengine.h> + +/* + * Definitions for the Freescale DMA controller's DMA_SLAVE implemention + * + * 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. + * + * 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. + */ + +/** + * 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 + * @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 { + + /* 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 7a0cb6064f83..296f9e747fac 100644 --- a/drivers/dma/fsldma.c +++ b/drivers/dma/fsldma.c @@ -34,6 +34,7 @@ #include <linux/dmapool.h> #include <linux/of_platform.h> +#include <asm/fsldma.h> #include "fsldma.h" static void dma_init(struct fsl_dma_chan *fsl_chan) @@ -552,6 +553,229 @@ fail: } /** + * fsl_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction + * @chan: DMA channel + * @sgl: scatterlist to transfer to/from + * @sg_len: number of entries in @scatterlist + * @direction: DMA direction + * @flags: DMAEngine flags + * + * Prepare a set of descriptors for a DMA_SLAVE transaction. Following the + * DMA_SLAVE API, this gets the device-specific information from the + * chan->private variable. + */ +static struct dma_async_tx_descriptor *fsl_dma_prep_slave_sg( + struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len, + enum dma_data_direction direction, unsigned long flags) +{ + struct fsl_dma_chan *fsl_chan; + struct fsl_desc_sw *first = NULL, *prev = NULL, *new = NULL; + struct fsl_dma_slave *slave; + struct list_head *tx_list; + 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 (!chan) + return NULL; + + if (!chan->private) + return NULL; + + fsl_chan = to_fsl_chan(chan); + slave = chan->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 + * + * 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 + */ + 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(fsl_chan); + if (!new) { + dev_err(fsl_chan->dev, "No free memory for " + "link descriptor\n"); + goto fail; + } +#ifdef FSL_DMA_LD_DEBUG + dev_dbg(fsl_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(fsl_chan, &new->hw, copy); + set_desc_src(fsl_chan, &new->hw, dma_src); + set_desc_dest(fsl_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(fsl_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(fsl_chan, new); + + /* Enable extra controller features */ + if (fsl_chan->set_src_loop_size) + fsl_chan->set_src_loop_size(fsl_chan, slave->src_loop_size); + + if (fsl_chan->set_dest_loop_size) + fsl_chan->set_dest_loop_size(fsl_chan, slave->dst_loop_size); + + if (fsl_chan->toggle_ext_start) + fsl_chan->toggle_ext_start(fsl_chan, slave->external_start); + + if (fsl_chan->toggle_ext_pause) + fsl_chan->toggle_ext_pause(fsl_chan, slave->external_pause); + + if (fsl_chan->set_request_count) + fsl_chan->set_request_count(fsl_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 + */ + tx_list = &first->tx_list; + list_for_each_entry_safe_reverse(new, prev, tx_list, node) { + list_del_init(&new->node); + dma_pool_free(fsl_chan->desc_pool, new, new->async_tx.phys); + } + + return NULL; +} + +static void fsl_dma_device_terminate_all(struct dma_chan *chan) +{ + struct fsl_dma_chan *fsl_chan; + struct fsl_desc_sw *desc, *tmp; + unsigned long flags; + + if (!chan) + return; + + fsl_chan = to_fsl_chan(chan); + + /* Halt the DMA engine */ + dma_halt(fsl_chan); + + spin_lock_irqsave(&fsl_chan->desc_lock, flags); + + /* Remove and free all of the descriptors in the LD queue */ + list_for_each_entry_safe(desc, tmp, &fsl_chan->ld_queue, node) { + list_del(&desc->node); + dma_pool_free(fsl_chan->desc_pool, desc, desc->async_tx.phys); + } + + spin_unlock_irqrestore(&fsl_chan->desc_lock, flags); +} + +/** * fsl_dma_update_completed_cookie - Update the completed cookie. * @fsl_chan : Freescale DMA channel */ @@ -977,12 +1201,15 @@ static int __devinit of_fsl_dma_probe(struct of_device *dev, dma_cap_set(DMA_MEMCPY, fdev->common.cap_mask); dma_cap_set(DMA_INTERRUPT, fdev->common.cap_mask); + dma_cap_set(DMA_SLAVE, fdev->common.cap_mask); fdev->common.device_alloc_chan_resources = fsl_dma_alloc_chan_resources; fdev->common.device_free_chan_resources = fsl_dma_free_chan_resources; fdev->common.device_prep_dma_interrupt = fsl_dma_prep_interrupt; fdev->common.device_prep_dma_memcpy = fsl_dma_prep_memcpy; fdev->common.device_is_tx_complete = fsl_dma_is_complete; fdev->common.device_issue_pending = fsl_dma_memcpy_issue_pending; + fdev->common.device_prep_slave_sg = fsl_dma_prep_slave_sg; + fdev->common.device_terminate_all = fsl_dma_device_terminate_all; fdev->common.dev = &dev->dev; fdev->irq = irq_of_parse_and_map(dev->node, 0); |