/* * Driver for the Atmel AHB DMA Controller (aka HDMA or DMAC on AT91 systems) * * Copyright (C) 2008 Atmel Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * * This supports the Atmel AHB DMA Controller, * * The driver has currently been tested with the Atmel AT91SAM9RL * and AT91SAM9G45 series. */ #include #include #include #include #include #include #include #include #include "at_hdmac_regs.h" /* * Glossary * -------- * * at_hdmac : Name of the ATmel AHB DMA Controller * at_dma_ / atdma : ATmel DMA controller entity related * atc_ / atchan : ATmel DMA Channel entity related */ #define ATC_DEFAULT_CFG (ATC_FIFOCFG_HALFFIFO) #define ATC_DEFAULT_CTRLA (0) #define ATC_DEFAULT_CTRLB (ATC_SIF(AT_DMA_MEM_IF) \ |ATC_DIF(AT_DMA_MEM_IF)) /* * Initial number of descriptors to allocate for each channel. This could * be increased during dma usage. */ static unsigned int init_nr_desc_per_channel = 64; module_param(init_nr_desc_per_channel, uint, 0644); MODULE_PARM_DESC(init_nr_desc_per_channel, "initial descriptors per channel (default: 64)"); /* prototypes */ static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx); /*----------------------------------------------------------------------*/ static struct at_desc *atc_first_active(struct at_dma_chan *atchan) { return list_first_entry(&atchan->active_list, struct at_desc, desc_node); } static struct at_desc *atc_first_queued(struct at_dma_chan *atchan) { return list_first_entry(&atchan->queue, struct at_desc, desc_node); } /** * atc_alloc_descriptor - allocate and return an initialized descriptor * @chan: the channel to allocate descriptors for * @gfp_flags: GFP allocation flags * * Note: The ack-bit is positioned in the descriptor flag at creation time * to make initial allocation more convenient. This bit will be cleared * and control will be given to client at usage time (during * preparation functions). */ static struct at_desc *atc_alloc_descriptor(struct dma_chan *chan, gfp_t gfp_flags) { struct at_desc *desc = NULL; struct at_dma *atdma = to_at_dma(chan->device); dma_addr_t phys; desc = dma_pool_alloc(atdma->dma_desc_pool, gfp_flags, &phys); if (desc) { memset(desc, 0, sizeof(struct at_desc)); INIT_LIST_HEAD(&desc->tx_list); dma_async_tx_descriptor_init(&desc->txd, chan); /* txd.flags will be overwritten in prep functions */ desc->txd.flags = DMA_CTRL_ACK; desc->txd.tx_submit = atc_tx_submit; desc->txd.phys = phys; } return desc; } /** * atc_desc_get - get an unused descriptor from free_list * @atchan: channel we want a new descriptor for */ static struct at_desc *atc_desc_get(struct at_dma_chan *atchan) { struct at_desc *desc, *_desc; struct at_desc *ret = NULL; unsigned long flags; unsigned int i = 0; LIST_HEAD(tmp_list); spin_lock_irqsave(&atchan->lock, flags); list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) { i++; if (async_tx_test_ack(&desc->txd)) { list_del(&desc->desc_node); ret = desc; break; } dev_dbg(chan2dev(&atchan->chan_common), "desc %p not ACKed\n", desc); } spin_unlock_irqrestore(&atchan->lock, flags); dev_vdbg(chan2dev(&atchan->chan_common), "scanned %u descriptors on freelist\n", i); /* no more descriptor available in initial pool: create one more */ if (!ret) { ret = atc_alloc_descriptor(&atchan->chan_common, GFP_ATOMIC); if (ret) { spin_lock_irqsave(&atchan->lock, flags); atchan->descs_allocated++; spin_unlock_irqrestore(&atchan->lock, flags); } else { dev_err(chan2dev(&atchan->chan_common), "not enough descriptors available\n"); } } return ret; } /** * atc_desc_put - move a descriptor, including any children, to the free list * @atchan: channel we work on * @desc: descriptor, at the head of a chain, to move to free list */ static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc) { if (desc) { struct at_desc *child; unsigned long flags; spin_lock_irqsave(&atchan->lock, flags); list_for_each_entry(child, &desc->tx_list, desc_node) dev_vdbg(chan2dev(&atchan->chan_common), "moving child desc %p to freelist\n", child); list_splice_init(&desc->tx_list, &atchan->free_list); dev_vdbg(chan2dev(&atchan->chan_common), "moving desc %p to freelist\n", desc); list_add(&desc->desc_node, &atchan->free_list); spin_unlock_irqrestore(&atchan->lock, flags); } } /** * atc_desc_chain - build chain adding a descripor * @first: address of first descripor of the chain * @prev: address of previous descripor of the chain * @desc: descriptor to queue * * Called from prep_* functions */ static void atc_desc_chain(struct at_desc **first, struct at_desc **prev, struct at_desc *desc) { if (!(*first)) { *first = desc; } else { /* inform the HW lli about chaining */ (*prev)->lli.dscr = desc->txd.phys; /* insert the link descriptor to the LD ring */ list_add_tail(&desc->desc_node, &(*first)->tx_list); } *prev = desc; } /** * atc_assign_cookie - compute and assign new cookie * @atchan: channel we work on * @desc: descriptor to assign cookie for * * Called with atchan->lock held and bh disabled */ static dma_cookie_t atc_assign_cookie(struct at_dma_chan *atchan, struct at_desc *desc) { dma_cookie_t cookie = atchan->chan_common.cookie; if (++cookie < 0) cookie = 1; atchan->chan_common.cookie = cookie; desc->txd.cookie = cookie; return cookie; } /** * atc_dostart - starts the DMA engine for real * @atchan: the channel we want to start * @first: first descriptor in the list we want to begin with * * Called with atchan->lock held and bh disabled */ static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first) { struct at_dma *atdma = to_at_dma(atchan->chan_common.device); /* ASSERT: channel is idle */ if (atc_chan_is_enabled(atchan)) { dev_err(chan2dev(&atchan->chan_common), "BUG: Attempted to start non-idle channel\n"); dev_err(chan2dev(&atchan->chan_common), " channel: s0x%x d0x%x ctrl0x%x:0x%x l0x%x\n", channel_readl(atchan, SADDR), channel_readl(atchan, DADDR), channel_readl(atchan, CTRLA), channel_readl(atchan, CTRLB), channel_readl(atchan, DSCR)); /* The tasklet will hopefully advance the queue... */ return; } vdbg_dump_regs(atchan); /* clear any pending interrupt */ while (dma_readl(atdma, EBCISR)) cpu_relax(); channel_writel(atchan, SADDR, 0); channel_writel(atchan, DADDR, 0); channel_writel(atchan, CTRLA, 0); channel_writel(atchan, CTRLB, 0); channel_writel(atchan, DSCR, first->txd.phys); dma_writel(atdma, CHER, atchan->mask); vdbg_dump_regs(atchan); } /** * atc_chain_complete - finish work for one transaction chain * @atchan: channel we work on * @desc: descriptor at the head of the chain we want do complete * * Called with atchan->lock held and bh disabled */ static void atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) { struct dma_async_tx_descriptor *txd = &desc->txd; dev_vdbg(chan2dev(&atchan->chan_common), "descriptor %u complete\n", txd->cookie); atchan->completed_cookie = txd->cookie; /* move children to free_list */ list_splice_init(&desc->tx_list, &atchan->free_list); /* move myself to free_list */ list_move(&desc->desc_node, &atchan->free_list); /* unmap dma addresses (not on slave channels) */ if (!atchan->chan_common.private) { struct device *parent = chan2parent(&atchan->chan_common); if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP)) { if (txd->flags & DMA_COMPL_DEST_UNMAP_SINGLE) dma_unmap_single(parent, desc->lli.daddr, desc->len, DMA_FROM_DEVICE); else dma_unmap_page(parent, desc->lli.daddr, desc->len, DMA_FROM_DEVICE); } if (!(txd->flags & DMA_COMPL_SKIP_SRC_UNMAP)) { if (txd->flags & DMA_COMPL_SRC_UNMAP_SINGLE) dma_unmap_single(parent, desc->lli.saddr, desc->len, DMA_TO_DEVICE); else dma_unmap_page(parent, desc->lli.saddr, desc->len, DMA_TO_DEVICE); } } /* for cyclic transfers, * no need to replay callback function while stopping */ if (!atc_chan_is_cyclic(atchan)) { dma_async_tx_callback callback = txd->callback; void *param = txd->callback_param; /* * The API requires that no submissions are done from a * callback, so we don't need to drop the lock here */ if (callback) callback(param); } dma_run_dependencies(txd); } /** * atc_complete_all - finish work for all transactions * @atchan: channel to complete transactions for * * Eventually submit queued descriptors if any * * Assume channel is idle while calling this function * Called with atchan->lock held and bh disabled */ static void atc_complete_all(struct at_dma_chan *atchan) { struct at_desc *desc, *_desc; LIST_HEAD(list); dev_vdbg(chan2dev(&atchan->chan_common), "complete all\n"); BUG_ON(atc_chan_is_enabled(atchan)); /* * Submit queued descriptors ASAP, i.e. before we go through * the completed ones. */ if (!list_empty(&atchan->queue)) atc_dostart(atchan, atc_first_queued(atchan)); /* empty active_list now it is completed */ list_splice_init(&atchan->active_list, &list); /* empty queue list by moving descriptors (if any) to active_list */ list_splice_init(&atchan->queue, &atchan->active_list); list_for_each_entry_safe(desc, _desc, &list, desc_node) atc_chain_complete(atchan, desc); } /** * atc_cleanup_descriptors - cleanup up finished descriptors in active_list * @atchan: channel to be cleaned up * * Called with atchan->lock held and bh disabled */ static void atc_cleanup_descriptors(struct at_dma_chan *atchan) { struct at_desc *desc, *_desc; struct at_desc *child; dev_vdbg(chan2dev(&atchan->chan_common), "cleanup descriptors\n"); list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) { if (!(desc->lli.ctrla & ATC_DONE)) /* This one is currently in progress */ return; list_for_each_entry(child, &desc->tx_list, desc_node) if (!(child->lli.ctrla & ATC_DONE)) /* Currently in progress */ return; /* * No descriptors so far seem to be in progress, i.e. * this chain must be done. */ atc_chain_complete(atchan, desc); } } /** * atc_advance_work - at the end of a transaction, move forward * @atchan: channel where the transaction ended * * Called with atchan->lock held and bh disabled */ static void atc_advance_work(struct at_dma_chan *atchan) { dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n"); if (list_empty(&atchan->active_list) || list_is_singular(&atchan->active_list)) { atc_complete_all(atchan); } else { atc_chain_complete(atchan, atc_first_active(atchan)); /* advance work */ atc_dostart(atchan, atc_first_active(atchan)); } } /** * atc_handle_error - handle errors reported by DMA controller * @atchan: channel where error occurs * * Called with atchan->lock held and bh disabled */ static void atc_handle_error(struct at_dma_chan *atchan) { struct at_desc *bad_desc; struct at_desc *child; /* * The descriptor currently at the head of the active list is * broked. Since we don't have any way to report errors, we'll * just have to scream loudly and try to carry on. */ bad_desc = atc_first_active(atchan); list_del_init(&bad_desc->desc_node); /* As we are stopped, take advantage to push queued descriptors * in active_list */ list_splice_init(&atchan->queue, atchan->active_list.prev); /* Try to restart the controller */ if (!list_empty(&atchan->active_list)) atc_dostart(atchan, atc_first_active(atchan)); /* * KERN_CRITICAL may seem harsh, but since this only happens * when someone submits a bad physical address in a * descriptor, we should consider ourselves lucky that the * controller flagged an error instead of scribbling over * random memory locations. */ dev_crit(chan2dev(&atchan->chan_common), "Bad descriptor submitted for DMA!\n"); dev_crit(chan2dev(&atchan->chan_common), " cookie: %d\n", bad_desc->txd.cookie); atc_dump_lli(atchan, &bad_desc->lli); list_for_each_entry(child, &bad_desc->tx_list, desc_node) atc_dump_lli(atchan, &child->lli); /* Pretend the descriptor completed successfully */ atc_chain_complete(atchan, bad_desc); } /** * atc_handle_cyclic - at the end of a period, run callback function * @atchan: channel used for cyclic operations * * Called with atchan->lock held and bh disabled */ static void atc_handle_cyclic(struct at_dma_chan *atchan) { struct at_desc *first = atc_first_active(atchan); struct dma_async_tx_descriptor *txd = &first->txd; dma_async_tx_callback callback = txd->callback; void *param = txd->callback_param; dev_vdbg(chan2dev(&atchan->chan_common), "new cyclic period llp 0x%08x\n", channel_readl(atchan, DSCR)); if (callback) callback(param); } /*-- IRQ & Tasklet ---------------------------------------------------*/ static void atc_tasklet(unsigned long data) { struct at_dma_chan *atchan = (struct at_dma_chan *)data; unsigned long flags; spin_lock_irqsave(&atchan->lock, flags); if (test_and_clear_bit(ATC_IS_ERROR, &atchan->status)) atc_handle_error(atchan); else if (atc_chan_is_cyclic(atchan)) atc_handle_cyclic(atchan); else atc_advance_work(atchan); spin_unlock_irqrestore(&atchan->lock, flags); } static irqreturn_t at_dma_interrupt(int irq, void *dev_id) { struct at_dma *atdma = (struct at_dma *)dev_id; struct at_dma_chan *atchan; int i; u32 status, pending, imr; int ret = IRQ_NONE; do { imr = dma_readl(atdma, EBCIMR); status = dma_readl(atdma, EBCISR); pending = status & imr; if (!pending) break; dev_vdbg(atdma->dma_common.dev, "interrupt: status = 0x%08x, 0x%08x, 0x%08x\n", status, imr, pending); for (i = 0; i < atdma->dma_common.chancnt; i++) { atchan = &atdma->chan[i]; if (pending & (AT_DMA_BTC(i) | AT_DMA_ERR(i))) { if (pending & AT_DMA_ERR(i)) { /* Disable channel on AHB error */ dma_writel(atdma, CHDR, AT_DMA_RES(i) | atchan->mask); /* Give information to tasklet */ set_bit(ATC_IS_ERROR, &atchan->status); } tasklet_schedule(&atchan->tasklet); ret = IRQ_HANDLED; } } } while (pending); return ret; } /*-- DMA Engine API --------------------------------------------------*/ /** * atc_tx_submit - set the prepared descriptor(s) to be executed by the engine * @desc: descriptor at the head of the transaction chain * * Queue chain if DMA engine is working already * * Cookie increment and adding to active_list or queue must be atomic */ static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx) { struct at_desc *desc = txd_to_at_desc(tx); struct at_dma_chan *atchan = to_at_dma_chan(tx->chan); dma_cookie_t cookie; unsigned long flags; spin_lock_irqsave(&atchan->lock, flags); cookie = atc_assign_cookie(atchan, desc); if (list_empty(&atchan->active_list)) { dev_vdbg(chan2dev(tx->chan), "tx_submit: started %u\n", desc->txd.cookie); atc_dostart(atchan, desc); list_add_tail(&desc->desc_node, &atchan->active_list); } else { dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n", desc->txd.cookie); list_add_tail(&desc->desc_node, &atchan->queue); } spin_unlock_irqrestore(&atchan->lock, flags); return cookie; } /** * atc_prep_dma_memcpy - prepare a memcpy operation * @chan: the channel to prepare operation on * @dest: operation virtual destination address * @src: operation virtual source address * @len: operation length * @flags: tx descriptor status flags */ static struct dma_async_tx_descriptor * atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, size_t len, unsigned long flags) { struct at_dma_chan *atchan = to_at_dma_chan(chan); struct at_desc *desc = NULL; struct at_desc *first = NULL; struct at_desc *prev = NULL; size_t xfer_count; size_t offset; unsigned int src_width; unsigned int dst_width; u32 ctrla; u32 ctrlb; dev_vdbg(chan2dev(chan), "prep_dma_memcpy: d0x%x s0x%x l0x%zx f0x%lx\n", dest, src, len, flags); if (unlikely(!len)) { dev_dbg(chan2dev(chan), "prep_dma_memcpy: length is zero!\n"); return NULL; } ctrla = ATC_DEFAULT_CTRLA; ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN | ATC_SRC_ADDR_MODE_INCR | ATC_DST_ADDR_MODE_INCR | ATC_FC_MEM2MEM; /* * We can be a lot more clever here, but this should take care * of the most common optimization. */ if (!((src | dest | len) & 3)) { ctrla |= ATC_SRC_WIDTH_WORD | ATC_DST_WIDTH_WORD; src_width = dst_width = 2; } else if (!((src | dest | len) & 1)) { ctrla |= ATC_SRC_WIDTH_HALFWORD | ATC_DST_WIDTH_HALFWORD; src_width = dst_width = 1; } else { ctrla |= ATC_SRC_WIDTH_BYTE | ATC_DST_WIDTH_BYTE; src_width = dst_width = 0; } for (offset = 0; offset < len; offset += xfer_count << src_width) { xfer_count = min_t(size_t, (len - offset) >> src_width, ATC_BTSIZE_MAX); desc = atc_desc_get(atchan); if (!desc) goto err_desc_get; desc->lli.saddr = src + offset; desc->lli.daddr = dest + offset; desc->lli.ctrla = ctrla | xfer_count; desc->lli.ctrlb = ctrlb; desc->txd.cookie = 0; atc_desc_chain(&first, &prev, desc); } /* First descriptor of the chain embedds additional information */ first->txd.cookie = -EBUSY; first->len = len; /* set end-of-link to the last link descriptor of list*/ set_desc_eol(desc); first->txd.flags = flags; /* client is in control of this ack */ return &first->txd; err_desc_get: atc_desc_put(atchan, first); return NULL; } /** * atc_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: tx descriptor status flags */ static struct dma_async_tx_descriptor * atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len, enum dma_data_direction direction, unsigned long flags) { struct at_dma_chan *atchan = to_at_dma_chan(chan); struct at_dma_slave *atslave = chan->private; struct at_desc *first = NULL; struct at_desc *prev = NULL; u32 ctrla; u32 ctrlb; dma_addr_t reg; unsigned int reg_width; unsigned int mem_width; unsigned int i; struct scatterlist *sg; size_t total_len = 0; dev_vdbg(chan2dev(chan), "prep_slave_sg (%d): %s f0x%lx\n", sg_len, direction == DMA_TO_DEVICE ? "TO DEVICE" : "FROM DEVICE", flags); if (unlikely(!atslave || !sg_len)) { dev_dbg(chan2dev(chan), "prep_dma_memcpy: length is zero!\n"); return NULL; } reg_width = atslave->reg_width; ctrla = ATC_DEFAULT_CTRLA | atslave->ctrla; ctrlb = ATC_IEN; switch (direction) { case DMA_TO_DEVICE: ctrla |= ATC_DST_WIDTH(reg_width); ctrlb |= ATC_DST_ADDR_MODE_FIXED | ATC_SRC_ADDR_MODE_INCR | ATC_FC_MEM2PER | ATC_SIF(AT_DMA_MEM_IF) | ATC_DIF(AT_DMA_PER_IF); reg = atslave->tx_reg; for_each_sg(sgl, sg, sg_len, i) { struct at_desc *desc; u32 len; u32 mem; desc = atc_desc_get(atchan); if (!desc) goto err_desc_get; mem = sg_dma_address(sg); len = sg_dma_len(sg); mem_width = 2; if (unlikely(mem & 3 || len & 3)) mem_width = 0; desc->lli.saddr = mem; desc->lli.daddr = reg; desc->lli.ctrla = ctrla | ATC_SRC_WIDTH(mem_width) | len >> mem_width; desc->lli.ctrlb = ctrlb; atc_desc_chain(&first, &prev, desc); total_len += len; } break; case DMA_FROM_DEVICE: ctrla |= ATC_SRC_WIDTH(reg_width); ctrlb |= ATC_DST_ADDR_MODE_INCR | ATC_SRC_ADDR_MODE_FIXED | ATC_FC_PER2MEM | ATC_SIF(AT_DMA_PER_IF) | ATC_DIF(AT_DMA_MEM_IF); reg = atslave->rx_reg; for_each_sg(sgl, sg, sg_len, i) { struct at_desc *desc; u32 len; u32 mem; desc = atc_desc_get(atchan); if (!desc) goto err_desc_get; mem = sg_dma_address(sg); len = sg_dma_len(sg); mem_width = 2; if (unlikely(mem & 3 || len & 3)) mem_width = 0; desc->lli.saddr = reg; desc->lli.daddr = mem; desc->lli.ctrla = ctrla | ATC_DST_WIDTH(mem_width) | len >> reg_width; desc->lli.ctrlb = ctrlb; atc_desc_chain(&first, &prev, desc); total_len += len; } break; default: return NULL; } /* set end-of-link to the last link descriptor of list*/ set_desc_eol(prev); /* First descriptor of the chain embedds additional information */ first->txd.cookie = -EBUSY; first->len = total_len; /* first link descriptor of list is responsible of flags */ first->txd.flags = flags; /* client is in control of this ack */ return &first->txd; err_desc_get: dev_err(chan2dev(chan), "not enough descriptors available\n"); atc_desc_put(atchan, first); return NULL; } /** * atc_dma_cyclic_check_values * Check for too big/unaligned periods and unaligned DMA buffer */ static int atc_dma_cyclic_check_values(unsigned int reg_width, dma_addr_t buf_addr, size_t period_len, enum dma_data_direction direction) { if (period_len > (ATC_BTSIZE_MAX << reg_width)) goto err_out; if (unlikely(period_len & ((1 << reg_width) - 1))) goto err_out; if (unlikely(buf_addr & ((1 << reg_width) - 1))) goto err_out; if (unlikely(!(direction & (DMA_TO_DEVICE | DMA_FROM_DEVICE)))) goto err_out; return 0; err_out: return -EINVAL; } /** * atc_dma_cyclic_fill_desc - Fill one period decriptor */ static int atc_dma_cyclic_fill_desc(struct at_dma_slave *atslave, struct at_desc *desc, unsigned int period_index, dma_addr_t buf_addr, size_t period_len, enum dma_data_direction direction) { u32 ctrla; unsigned int reg_width = atslave->reg_width; /* prepare common CRTLA value */ ctrla = ATC_DEFAULT_CTRLA | atslave->ctrla | ATC_DST_WIDTH(reg_width) | ATC_SRC_WIDTH(reg_width) | period_len >> reg_width; switch (direction) { case DMA_TO_DEVICE: desc->lli.saddr = buf_addr + (period_len * period_index); desc->lli.daddr = atslave->tx_reg; desc->lli.ctrla = ctrla; desc->lli.ctrlb = ATC_DST_ADDR_MODE_FIXED | ATC_SRC_ADDR_MODE_INCR | ATC_FC_MEM2PER | ATC_SIF(AT_DMA_MEM_IF) | ATC_DIF(AT_DMA_PER_IF); break; case DMA_FROM_DEVICE: desc->lli.saddr = atslave->rx_reg; desc->lli.daddr = buf_addr + (period_len * period_index); desc->lli.ctrla = ctrla; desc->lli.ctrlb = ATC_DST_ADDR_MODE_INCR | ATC_SRC_ADDR_MODE_FIXED | ATC_FC_PER2MEM | ATC_SIF(AT_DMA_PER_IF) | ATC_DIF(AT_DMA_MEM_IF); break; default: return -EINVAL; } return 0; } /** * atc_prep_dma_cyclic - prepare the cyclic DMA transfer * @chan: the DMA channel to prepare * @buf_addr: physical DMA address where the buffer starts * @buf_len: total number of bytes for the entire buffer * @period_len: number of bytes for each period * @direction: transfer direction, to or from device */ static struct dma_async_tx_descriptor * atc_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, size_t period_len, enum dma_data_direction direction) { struct at_dma_chan *atchan = to_at_dma_chan(chan); struct at_dma_slave *atslave = chan->private; struct at_desc *first = NULL; struct at_desc *prev = NULL; unsigned long was_cyclic; unsigned int periods = buf_len / period_len; unsigned int i; dev_vdbg(chan2dev(chan), "prep_dma_cyclic: %s buf@0x%08x - %d (%d/%d)\n", direction == DMA_TO_DEVICE ? "TO DEVICE" : "FROM DEVICE", buf_addr, periods, buf_len, period_len); if (unlikely(!atslave || !buf_len || !period_len)) { dev_dbg(chan2dev(chan), "prep_dma_cyclic: length is zero!\n"); return NULL; } was_cyclic = test_and_set_bit(ATC_IS_CYCLIC, &atchan->status); if (was_cyclic) { dev_dbg(chan2dev(chan), "prep_dma_cyclic: channel in use!\n"); return NULL; } /* Check for too big/unaligned periods and unaligned DMA buffer */ if (atc_dma_cyclic_check_values(atslave->reg_width, buf_addr, period_len, direction)) goto err_out; /* build cyclic linked list */ for (i = 0; i < periods; i++) { struct at_desc *desc; desc = atc_desc_get(atchan); if (!desc) goto err_desc_get; if (atc_dma_cyclic_fill_desc(atslave, desc, i, buf_addr, period_len, direction)) goto err_desc_get; atc_desc_chain(&first, &prev, desc); } /* lets make a cyclic list */ prev->lli.dscr = first->txd.phys; /* First descriptor of the chain embedds additional information */ first->txd.cookie = -EBUSY; first->len = buf_len; return &first->txd; err_desc_get: dev_err(chan2dev(chan), "not enough descriptors available\n"); atc_desc_put(atchan, first); err_out: clear_bit(ATC_IS_CYCLIC, &atchan->status); return NULL; } static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned long arg) { struct at_dma_chan *atchan = to_at_dma_chan(chan); struct at_dma *atdma = to_at_dma(chan->device); int chan_id = atchan->chan_common.chan_id; unsigned long flags; LIST_HEAD(list); dev_vdbg(chan2dev(chan), "atc_control (%d)\n", cmd); if (cmd == DMA_PAUSE) { spin_lock_irqsave(&atchan->lock, flags); dma_writel(atdma, CHER, AT_DMA_SUSP(chan_id)); set_bit(ATC_IS_PAUSED, &atchan->status); spin_unlock_irqrestore(&atchan->lock, flags); } else if (cmd == DMA_RESUME) { if (!atc_chan_is_paused(atchan)) return 0; spin_lock_irqsave(&atchan->lock, flags); dma_writel(atdma, CHDR, AT_DMA_RES(chan_id)); clear_bit(ATC_IS_PAUSED, &atchan->status); spin_unlock_irqrestore(&atchan->lock, flags); } else if (cmd == DMA_TERMINATE_ALL) { struct at_desc *desc, *_desc; /* * This is only called when something went wrong elsewhere, so * we don't really care about the data. Just disable the * channel. We still have to poll the channel enable bit due * to AHB/HSB limitations. */ spin_lock_irqsave(&atchan->lock, flags); /* disabling channel: must also remove suspend state */ dma_writel(atdma, CHDR, AT_DMA_RES(chan_id) | atchan->mask); /* confirm that this channel is disabled */ while (dma_readl(atdma, CHSR) & atchan->mask) cpu_relax(); /* active_list entries will end up before queued entries */ list_splice_init(&atchan->queue, &list); list_splice_init(&atchan->active_list, &list); /* Flush all pending and queued descriptors */ list_for_each_entry_safe(desc, _desc, &list, desc_node) atc_chain_complete(atchan, desc); clear_bit(ATC_IS_PAUSED, &atchan->status); /* if channel dedicated to cyclic operations, free it */ clear_bit(ATC_IS_CYCLIC, &atchan->status); spin_unlock_irqrestore(&atchan->lock, flags); } else { return -ENXIO; } return 0; } /** * atc_tx_status - poll for transaction completion * @chan: DMA channel * @cookie: transaction identifier to check status of * @txstate: if not %NULL updated with transaction state * * If @txstate is passed in, upon return it reflect the driver * internal state and can be used with dma_async_is_complete() to check * the status of multiple cookies without re-checking hardware state. */ static enum dma_status atc_tx_status(struct dma_chan *chan, dma_cookie_t cookie, struct dma_tx_state *txstate) { struct at_dma_chan *atchan = to_at_dma_chan(chan); dma_cookie_t last_used; dma_cookie_t last_complete; unsigned long flags; enum dma_status ret; spin_lock_irqsave(&atchan->lock, flags); last_complete = atchan->completed_cookie; last_used = chan->cookie; ret = dma_async_is_complete(cookie, last_complete, last_used); if (ret != DMA_SUCCESS) { atc_cleanup_descriptors(atchan); last_complete = atchan->completed_cookie; last_used = chan->cookie; ret = dma_async_is_complete(cookie, last_complete, last_used); } spin_unlock_irqrestore(&atchan->lock, flags); if (ret != DMA_SUCCESS) dma_set_tx_state(txstate, last_complete, last_used, atc_first_active(atchan)->len); else dma_set_tx_state(txstate, last_complete, last_used, 0); if (atc_chan_is_paused(atchan)) ret = DMA_PAUSED; dev_vdbg(chan2dev(chan), "tx_status %d: cookie = %d (d%d, u%d)\n", ret, cookie, last_complete ? last_complete : 0, last_used ? last_used : 0); return ret; } /** * atc_issue_pending - try to finish work * @chan: target DMA channel */ static void atc_issue_pending(struct dma_chan *chan) { struct at_dma_chan *atchan = to_at_dma_chan(chan); unsigned long flags; dev_vdbg(chan2dev(chan), "issue_pending\n"); /* Not needed for cyclic transfers */ if (atc_chan_is_cyclic(atchan)) return; spin_lock_irqsave(&atchan->lock, flags); if (!atc_chan_is_enabled(atchan)) { atc_advance_work(atchan); } spin_unlock_irqrestore(&atchan->lock, flags); } /** * atc_alloc_chan_resources - allocate resources for DMA channel * @chan: allocate descriptor resources for this channel * @client: current client requesting the channel be ready for requests * * return - the number of allocated descriptors */ static int atc_alloc_chan_resources(struct dma_chan *chan) { struct at_dma_chan *atchan = to_at_dma_chan(chan); struct at_dma *atdma = to_at_dma(chan->device); struct at_desc *desc; struct at_dma_slave *atslave; unsigned long flags; int i; u32 cfg; LIST_HEAD(tmp_list); dev_vdbg(chan2dev(chan), "alloc_chan_resources\n"); /* ASSERT: channel is idle */ if (atc_chan_is_enabled(atchan)) { dev_dbg(chan2dev(chan), "DMA channel not idle ?\n"); return -EIO; } cfg = ATC_DEFAULT_CFG; atslave = chan->private; if (atslave) { /* * We need controller-specific data to set up slave * transfers. */ BUG_ON(!atslave->dma_dev || atslave->dma_dev != atdma->dma_common.dev); /* if cfg configuration specified take it instad of default */ if (atslave->cfg) cfg = atslave->cfg; } /* have we already been set up? * reconfigure channel but no need to reallocate descriptors */ if (!list_empty(&atchan->free_list)) return atchan->descs_allocated; /* Allocate initial pool of descriptors */ for (i = 0; i < init_nr_desc_per_channel; i++) { desc = atc_alloc_descriptor(chan, GFP_KERNEL); if (!desc) { dev_err(atdma->dma_common.dev, "Only %d initial descriptors\n", i); break; } list_add_tail(&desc->desc_node, &tmp_list); } spin_lock_irqsave(&atchan->lock, flags); atchan->descs_allocated = i; list_splice(&tmp_list, &atchan->free_list); atchan->completed_cookie = chan->cookie = 1; spin_unlock_irqrestore(&atchan->lock, flags); /* channel parameters */ channel_writel(atchan, CFG, cfg); dev_dbg(chan2dev(chan), "alloc_chan_resources: allocated %d descriptors\n", atchan->descs_allocated); return atchan->descs_allocated; } /** * atc_free_chan_resources - free all channel resources * @chan: DMA channel */ static void atc_free_chan_resources(struct dma_chan *chan) { struct at_dma_chan *atchan = to_at_dma_chan(chan); struct at_dma *atdma = to_at_dma(chan->device); struct at_desc *desc, *_desc; LIST_HEAD(list); dev_dbg(chan2dev(chan), "free_chan_resources: (descs allocated=%u)\n", atchan->descs_allocated); /* ASSERT: channel is idle */ BUG_ON(!list_empty(&atchan->active_list)); BUG_ON(!list_empty(&atchan->queue)); BUG_ON(atc_chan_is_enabled(atchan)); list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) { dev_vdbg(chan2dev(chan), " freeing descriptor %p\n", desc); list_del(&desc->desc_node); /* free link descriptor */ dma_pool_free(atdma->dma_desc_pool, desc, desc->txd.phys); } list_splice_init(&atchan->free_list, &list); atchan->descs_allocated = 0; atchan->status = 0; dev_vdbg(chan2dev(chan), "free_chan_resources: done\n"); } /*-- Module Management -----------------------------------------------*/ /** * at_dma_off - disable DMA controller * @atdma: the Atmel HDAMC device */ static void at_dma_off(struct at_dma *atdma) { dma_writel(atdma, EN, 0); /* disable all interrupts */ dma_writel(atdma, EBCIDR, -1L); /* confirm that all channels are disabled */ while (dma_readl(atdma, CHSR) & atdma->all_chan_mask) cpu_relax(); } static int __init at_dma_probe(struct platform_device *pdev) { struct at_dma_platform_data *pdata; struct resource *io; struct at_dma *atdma; size_t size; int irq; int err; int i; /* get DMA Controller parameters from platform */ pdata = pdev->dev.platform_data; if (!pdata || pdata->nr_channels > AT_DMA_MAX_NR_CHANNELS) return -EINVAL; io = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!io) return -EINVAL; irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; size = sizeof(struct at_dma); size += pdata->nr_channels * sizeof(struct at_dma_chan); atdma = kzalloc(size, GFP_KERNEL); if (!atdma) return -ENOMEM; /* discover transaction capabilites from the platform data */ atdma->dma_common.cap_mask = pdata->cap_mask; atdma->all_chan_mask = (1 << pdata->nr_channels) - 1; size = resource_size(io); if (!request_mem_region(io->start, size, pdev->dev.driver->name)) { err = -EBUSY; goto err_kfree; } atdma->regs = ioremap(io->start, size); if (!atdma->regs) { err = -ENOMEM; goto err_release_r; } atdma->clk = clk_get(&pdev->dev, "dma_clk"); if (IS_ERR(atdma->clk)) { err = PTR_ERR(atdma->clk); goto err_clk; } clk_enable(atdma->clk); /* force dma off, just in case */ at_dma_off(atdma); err = request_irq(irq, at_dma_interrupt, 0, "at_hdmac", atdma); if (err) goto err_irq; platform_set_drvdata(pdev, atdma); /* create a pool of consistent memory blocks for hardware descriptors */ atdma->dma_desc_pool = dma_pool_create("at_hdmac_desc_pool", &pdev->dev, sizeof(struct at_desc), 4 /* word alignment */, 0); if (!atdma->dma_desc_pool) { dev_err(&pdev->dev, "No memory for descriptors dma pool\n"); err = -ENOMEM; goto err_pool_create; } /* clear any pending interrupt */ while (dma_readl(atdma, EBCISR)) cpu_relax(); /* initialize channels related values */ INIT_LIST_HEAD(&atdma->dma_common.channels); for (i = 0; i < pdata->nr_channels; i++) { struct at_dma_chan *atchan = &atdma->chan[i]; atchan->chan_common.device = &atdma->dma_common; atchan->chan_common.cookie = atchan->completed_cookie = 1; list_add_tail(&atchan->chan_common.device_node, &atdma->dma_common.channels); atchan->ch_regs = atdma->regs + ch_regs(i); spin_lock_init(&atchan->lock); atchan->mask = 1 << i; INIT_LIST_HEAD(&atchan->active_list); INIT_LIST_HEAD(&atchan->queue); INIT_LIST_HEAD(&atchan->free_list); tasklet_init(&atchan->tasklet, atc_tasklet, (unsigned long)atchan); atc_enable_irq(atchan); } /* set base routines */ atdma->dma_common.device_alloc_chan_resources = atc_alloc_chan_resources; atdma->dma_common.device_free_chan_resources = atc_free_chan_resources; atdma->dma_common.device_tx_status = atc_tx_status; atdma->dma_common.device_issue_pending = atc_issue_pending; atdma->dma_common.dev = &pdev->dev; /* set prep routines based on capability */ if (dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask)) atdma->dma_common.device_prep_dma_memcpy = atc_prep_dma_memcpy; if (dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)) { atdma->dma_common.device_prep_slave_sg = atc_prep_slave_sg; /* controller can do slave DMA: can trigger cyclic transfers */ dma_cap_set(DMA_CYCLIC, atdma->dma_common.cap_mask); atdma->dma_common.device_prep_dma_cyclic = atc_prep_dma_cyclic; atdma->dma_common.device_control = atc_control; } dma_writel(atdma, EN, AT_DMA_ENABLE); dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s), %d channels\n", dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "", dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask) ? "slave " : "", pdata->nr_channels); dma_async_device_register(&atdma->dma_common); return 0; err_pool_create: platform_set_drvdata(pdev, NULL); free_irq(platform_get_irq(pdev, 0), atdma); err_irq: clk_disable(atdma->clk); clk_put(atdma->clk); err_clk: iounmap(atdma->regs); atdma->regs = NULL; err_release_r: release_mem_region(io->start, size); err_kfree: kfree(atdma); return err; } static int __exit at_dma_remove(struct platform_device *pdev) { struct at_dma *atdma = platform_get_drvdata(pdev); struct dma_chan *chan, *_chan; struct resource *io; at_dma_off(atdma); dma_async_device_unregister(&atdma->dma_common); dma_pool_destroy(atdma->dma_desc_pool); platform_set_drvdata(pdev, NULL); free_irq(platform_get_irq(pdev, 0), atdma); list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels, device_node) { struct at_dma_chan *atchan = to_at_dma_chan(chan); /* Disable interrupts */ atc_disable_irq(atchan); tasklet_disable(&atchan->tasklet); tasklet_kill(&atchan->tasklet); list_del(&chan->device_node); } clk_disable(atdma->clk); clk_put(atdma->clk); iounmap(atdma->regs); atdma->regs = NULL; io = platform_get_resource(pdev, IORESOURCE_MEM, 0); release_mem_region(io->start, resource_size(io)); kfree(atdma); return 0; } static void at_dma_shutdown(struct platform_device *pdev) { struct at_dma *atdma = platform_get_drvdata(pdev); at_dma_off(platform_get_drvdata(pdev)); clk_disable(atdma->clk); } static int at_dma_prepare(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct at_dma *atdma = platform_get_drvdata(pdev); struct dma_chan *chan, *_chan; list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels, device_node) { struct at_dma_chan *atchan = to_at_dma_chan(chan); /* wait for transaction completion (except in cyclic case) */ if (atc_chan_is_enabled(atchan) && !atc_chan_is_cyclic(atchan)) return -EAGAIN; } return 0; } static void atc_suspend_cyclic(struct at_dma_chan *atchan) { struct dma_chan *chan = &atchan->chan_common; /* Channel should be paused by user * do it anyway even if it is not done already */ if (!atc_chan_is_paused(atchan)) { dev_warn(chan2dev(chan), "cyclic channel not paused, should be done by channel user\n"); atc_control(chan, DMA_PAUSE, 0); } /* now preserve additional data for cyclic operations */ /* next descriptor address in the cyclic list */ atchan->save_dscr = channel_readl(atchan, DSCR); vdbg_dump_regs(atchan); } static int at_dma_suspend_noirq(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct at_dma *atdma = platform_get_drvdata(pdev); struct dma_chan *chan, *_chan; /* preserve data */ list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels, device_node) { struct at_dma_chan *atchan = to_at_dma_chan(chan); if (atc_chan_is_cyclic(atchan)) atc_suspend_cyclic(atchan); atchan->save_cfg = channel_readl(atchan, CFG); } atdma->save_imr = dma_readl(atdma, EBCIMR); /* disable DMA controller */ at_dma_off(atdma); clk_disable(atdma->clk); return 0; } static void atc_resume_cyclic(struct at_dma_chan *atchan) { struct at_dma *atdma = to_at_dma(atchan->chan_common.device); /* restore channel status for cyclic descriptors list: * next descriptor in the cyclic list at the time of suspend */ channel_writel(atchan, SADDR, 0); channel_writel(atchan, DADDR, 0); channel_writel(atchan, CTRLA, 0); channel_writel(atchan, CTRLB, 0); channel_writel(atchan, DSCR, atchan->save_dscr); dma_writel(atdma, CHER, atchan->mask); /* channel pause status should be removed by channel user * We cannot take the initiative to do it here */ vdbg_dump_regs(atchan); } static int at_dma_resume_noirq(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct at_dma *atdma = platform_get_drvdata(pdev); struct dma_chan *chan, *_chan; /* bring back DMA controller */ clk_enable(atdma->clk); dma_writel(atdma, EN, AT_DMA_ENABLE); /* clear any pending interrupt */ while (dma_readl(atdma, EBCISR)) cpu_relax(); /* restore saved data */ dma_writel(atdma, EBCIER, atdma->save_imr); list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels, device_node) { struct at_dma_chan *atchan = to_at_dma_chan(chan); channel_writel(atchan, CFG, atchan->save_cfg); if (atc_chan_is_cyclic(atchan)) atc_resume_cyclic(atchan); } return 0; } static const struct dev_pm_ops at_dma_dev_pm_ops = { .prepare = at_dma_prepare, .suspend_noirq = at_dma_suspend_noirq, .resume_noirq = at_dma_resume_noirq, }; static struct platform_driver at_dma_driver = { .remove = __exit_p(at_dma_remove), .shutdown = at_dma_shutdown, .driver = { .name = "at_hdmac", .pm = &at_dma_dev_pm_ops, }, }; static int __init at_dma_init(void) { return platform_driver_probe(&at_dma_driver, at_dma_probe); } subsys_initcall(at_dma_init); static void __exit at_dma_exit(void) { platform_driver_unregister(&at_dma_driver); } module_exit(at_dma_exit); MODULE_DESCRIPTION("Atmel AHB DMA Controller driver"); MODULE_AUTHOR("Nicolas Ferre "); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:at_hdmac");