diff options
Diffstat (limited to 'drivers/dma/dw_dmac.c')
| -rw-r--r-- | drivers/dma/dw_dmac.c | 1122 |
1 files changed, 1122 insertions, 0 deletions
diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c new file mode 100644 index 00000000000..94df9177124 --- /dev/null +++ b/drivers/dma/dw_dmac.c @@ -0,0 +1,1122 @@ +/* + * Driver for the Synopsys DesignWare DMA Controller (aka DMACA on + * AVR32 systems.) + * + * Copyright (C) 2007-2008 Atmel Corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +#include "dw_dmac_regs.h" + +/* + * This supports the Synopsys "DesignWare AHB Central DMA Controller", + * (DW_ahb_dmac) which is used with various AMBA 2.0 systems (not all + * of which use ARM any more). See the "Databook" from Synopsys for + * information beyond what licensees probably provide. + * + * The driver has currently been tested only with the Atmel AT32AP7000, + * which does not support descriptor writeback. + */ + +/* NOTE: DMS+SMS is system-specific. We should get this information + * from the platform code somehow. + */ +#define DWC_DEFAULT_CTLLO (DWC_CTLL_DST_MSIZE(0) \ + | DWC_CTLL_SRC_MSIZE(0) \ + | DWC_CTLL_DMS(0) \ + | DWC_CTLL_SMS(1) \ + | DWC_CTLL_LLP_D_EN \ + | DWC_CTLL_LLP_S_EN) + +/* + * This is configuration-dependent and usually a funny size like 4095. + * Let's round it down to the nearest power of two. + * + * Note that this is a transfer count, i.e. if we transfer 32-bit + * words, we can do 8192 bytes per descriptor. + * + * This parameter is also system-specific. + */ +#define DWC_MAX_COUNT 2048U + +/* + * Number of descriptors to allocate for each channel. This should be + * made configurable somehow; preferably, the clients (at least the + * ones using slave transfers) should be able to give us a hint. + */ +#define NR_DESCS_PER_CHANNEL 64 + +/*----------------------------------------------------------------------*/ + +/* + * Because we're not relying on writeback from the controller (it may not + * even be configured into the core!) we don't need to use dma_pool. These + * descriptors -- and associated data -- are cacheable. We do need to make + * sure their dcache entries are written back before handing them off to + * the controller, though. + */ + +static struct dw_desc *dwc_first_active(struct dw_dma_chan *dwc) +{ + return list_entry(dwc->active_list.next, struct dw_desc, desc_node); +} + +static struct dw_desc *dwc_first_queued(struct dw_dma_chan *dwc) +{ + return list_entry(dwc->queue.next, struct dw_desc, desc_node); +} + +static struct dw_desc *dwc_desc_get(struct dw_dma_chan *dwc) +{ + struct dw_desc *desc, *_desc; + struct dw_desc *ret = NULL; + unsigned int i = 0; + + spin_lock_bh(&dwc->lock); + list_for_each_entry_safe(desc, _desc, &dwc->free_list, desc_node) { + if (async_tx_test_ack(&desc->txd)) { + list_del(&desc->desc_node); + ret = desc; + break; + } + dev_dbg(&dwc->chan.dev, "desc %p not ACKed\n", desc); + i++; + } + spin_unlock_bh(&dwc->lock); + + dev_vdbg(&dwc->chan.dev, "scanned %u descriptors on freelist\n", i); + + return ret; +} + +static void dwc_sync_desc_for_cpu(struct dw_dma_chan *dwc, struct dw_desc *desc) +{ + struct dw_desc *child; + + list_for_each_entry(child, &desc->txd.tx_list, desc_node) + dma_sync_single_for_cpu(dwc->chan.dev.parent, + child->txd.phys, sizeof(child->lli), + DMA_TO_DEVICE); + dma_sync_single_for_cpu(dwc->chan.dev.parent, + desc->txd.phys, sizeof(desc->lli), + DMA_TO_DEVICE); +} + +/* + * Move a descriptor, including any children, to the free list. + * `desc' must not be on any lists. + */ +static void dwc_desc_put(struct dw_dma_chan *dwc, struct dw_desc *desc) +{ + if (desc) { + struct dw_desc *child; + + dwc_sync_desc_for_cpu(dwc, desc); + + spin_lock_bh(&dwc->lock); + list_for_each_entry(child, &desc->txd.tx_list, desc_node) + dev_vdbg(&dwc->chan.dev, + "moving child desc %p to freelist\n", + child); + list_splice_init(&desc->txd.tx_list, &dwc->free_list); + dev_vdbg(&dwc->chan.dev, "moving desc %p to freelist\n", desc); + list_add(&desc->desc_node, &dwc->free_list); + spin_unlock_bh(&dwc->lock); + } +} + +/* Called with dwc->lock held and bh disabled */ +static dma_cookie_t +dwc_assign_cookie(struct dw_dma_chan *dwc, struct dw_desc *desc) +{ + dma_cookie_t cookie = dwc->chan.cookie; + + if (++cookie < 0) + cookie = 1; + + dwc->chan.cookie = cookie; + desc->txd.cookie = cookie; + + return cookie; +} + +/*----------------------------------------------------------------------*/ + +/* Called with dwc->lock held and bh disabled */ +static void dwc_dostart(struct dw_dma_chan *dwc, struct dw_desc *first) +{ + struct dw_dma *dw = to_dw_dma(dwc->chan.device); + + /* ASSERT: channel is idle */ + if (dma_readl(dw, CH_EN) & dwc->mask) { + dev_err(&dwc->chan.dev, + "BUG: Attempted to start non-idle channel\n"); + dev_err(&dwc->chan.dev, + " SAR: 0x%x DAR: 0x%x LLP: 0x%x CTL: 0x%x:%08x\n", + channel_readl(dwc, SAR), + channel_readl(dwc, DAR), + channel_readl(dwc, LLP), + channel_readl(dwc, CTL_HI), + channel_readl(dwc, CTL_LO)); + + /* The tasklet will hopefully advance the queue... */ + return; + } + + channel_writel(dwc, LLP, first->txd.phys); + channel_writel(dwc, CTL_LO, + DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN); + channel_writel(dwc, CTL_HI, 0); + channel_set_bit(dw, CH_EN, dwc->mask); +} + +/*----------------------------------------------------------------------*/ + +static void +dwc_descriptor_complete(struct dw_dma_chan *dwc, struct dw_desc *desc) +{ + dma_async_tx_callback callback; + void *param; + struct dma_async_tx_descriptor *txd = &desc->txd; + + dev_vdbg(&dwc->chan.dev, "descriptor %u complete\n", txd->cookie); + + dwc->completed = txd->cookie; + callback = txd->callback; + param = txd->callback_param; + + dwc_sync_desc_for_cpu(dwc, desc); + list_splice_init(&txd->tx_list, &dwc->free_list); + list_move(&desc->desc_node, &dwc->free_list); + + /* + * We use dma_unmap_page() regardless of how the buffers were + * mapped before they were submitted... + */ + if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP)) + dma_unmap_page(dwc->chan.dev.parent, desc->lli.dar, desc->len, + DMA_FROM_DEVICE); + if (!(txd->flags & DMA_COMPL_SKIP_SRC_UNMAP)) + dma_unmap_page(dwc->chan.dev.parent, desc->lli.sar, desc->len, + DMA_TO_DEVICE); + + /* + * 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); +} + +static void dwc_complete_all(struct dw_dma *dw, struct dw_dma_chan *dwc) +{ + struct dw_desc *desc, *_desc; + LIST_HEAD(list); + + if (dma_readl(dw, CH_EN) & dwc->mask) { + dev_err(&dwc->chan.dev, + "BUG: XFER bit set, but channel not idle!\n"); + + /* Try to continue after resetting the channel... */ + channel_clear_bit(dw, CH_EN, dwc->mask); + while (dma_readl(dw, CH_EN) & dwc->mask) + cpu_relax(); + } + + /* + * Submit queued descriptors ASAP, i.e. before we go through + * the completed ones. + */ + if (!list_empty(&dwc->queue)) + dwc_dostart(dwc, dwc_first_queued(dwc)); + list_splice_init(&dwc->active_list, &list); + list_splice_init(&dwc->queue, &dwc->active_list); + + list_for_each_entry_safe(desc, _desc, &list, desc_node) + dwc_descriptor_complete(dwc, desc); +} + +static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc) +{ + dma_addr_t llp; + struct dw_desc *desc, *_desc; + struct dw_desc *child; + u32 status_xfer; + + /* + * Clear block interrupt flag before scanning so that we don't + * miss any, and read LLP before RAW_XFER to ensure it is + * valid if we decide to scan the list. + */ + dma_writel(dw, CLEAR.BLOCK, dwc->mask); + llp = channel_readl(dwc, LLP); + status_xfer = dma_readl(dw, RAW.XFER); + + if (status_xfer & dwc->mask) { + /* Everything we've submitted is done */ + dma_writel(dw, CLEAR.XFER, dwc->mask); + dwc_complete_all(dw, dwc); + return; + } + + dev_vdbg(&dwc->chan.dev, "scan_descriptors: llp=0x%x\n", llp); + + list_for_each_entry_safe(desc, _desc, &dwc->active_list, desc_node) { + if (desc->lli.llp == llp) + /* This one is currently in progress */ + return; + + list_for_each_entry(child, &desc->txd.tx_list, desc_node) + if (child->lli.llp == llp) + /* Currently in progress */ + return; + + /* + * No descriptors so far seem to be in progress, i.e. + * this one must be done. + */ + dwc_descriptor_complete(dwc, desc); + } + + dev_err(&dwc->chan.dev, + "BUG: All descriptors done, but channel not idle!\n"); + + /* Try to continue after resetting the channel... */ + channel_clear_bit(dw, CH_EN, dwc->mask); + while (dma_readl(dw, CH_EN) & dwc->mask) + cpu_relax(); + + if (!list_empty(&dwc->queue)) { + dwc_dostart(dwc, dwc_first_queued(dwc)); + list_splice_init(&dwc->queue, &dwc->active_list); + } +} + +static void dwc_dump_lli(struct dw_dma_chan *dwc, struct dw_lli *lli) +{ + dev_printk(KERN_CRIT, &dwc->chan.dev, + " desc: s0x%x d0x%x l0x%x c0x%x:%x\n", + lli->sar, lli->dar, lli->llp, + lli->ctlhi, lli->ctllo); +} + +static void dwc_handle_error(struct dw_dma *dw, struct dw_dma_chan *dwc) +{ + struct dw_desc *bad_desc; + struct dw_desc *child; + + dwc_scan_descriptors(dw, dwc); + + /* + * The descriptor currently at the head of the active list is + * borked. Since we don't have any way to report errors, we'll + * just have to scream loudly and try to carry on. + */ + bad_desc = dwc_first_active(dwc); + list_del_init(&bad_desc->desc_node); + list_splice_init(&dwc->queue, dwc->active_list.prev); + + /* Clear the error flag and try to restart the controller */ + dma_writel(dw, CLEAR.ERROR, dwc->mask); + if (!list_empty(&dwc->active_list)) + dwc_dostart(dwc, dwc_first_active(dwc)); + + /* + * 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_printk(KERN_CRIT, &dwc->chan.dev, + "Bad descriptor submitted for DMA!\n"); + dev_printk(KERN_CRIT, &dwc->chan.dev, + " cookie: %d\n", bad_desc->txd.cookie); + dwc_dump_lli(dwc, &bad_desc->lli); + list_for_each_entry(child, &bad_desc->txd.tx_list, desc_node) + dwc_dump_lli(dwc, &child->lli); + + /* Pretend the descriptor completed successfully */ + dwc_descriptor_complete(dwc, bad_desc); +} + +static void dw_dma_tasklet(unsigned long data) +{ + struct dw_dma *dw = (struct dw_dma *)data; + struct dw_dma_chan *dwc; + u32 status_block; + u32 status_xfer; + u32 status_err; + int i; + + status_block = dma_readl(dw, RAW.BLOCK); + status_xfer = dma_readl(dw, RAW.BLOCK); + status_err = dma_readl(dw, RAW.ERROR); + + dev_vdbg(dw->dma.dev, "tasklet: status_block=%x status_err=%x\n", + status_block, status_err); + + for (i = 0; i < dw->dma.chancnt; i++) { + dwc = &dw->chan[i]; + spin_lock(&dwc->lock); + if (status_err & (1 << i)) + dwc_handle_error(dw, dwc); + else if ((status_block | status_xfer) & (1 << i)) + dwc_scan_descriptors(dw, dwc); + spin_unlock(&dwc->lock); + } + + /* + * Re-enable interrupts. Block Complete interrupts are only + * enabled if the INT_EN bit in the descriptor is set. This + * will trigger a scan before the whole list is done. + */ + channel_set_bit(dw, MASK.XFER, dw->all_chan_mask); + channel_set_bit(dw, MASK.BLOCK, dw->all_chan_mask); + channel_set_bit(dw, MASK.ERROR, dw->all_chan_mask); +} + +static irqreturn_t dw_dma_interrupt(int irq, void *dev_id) +{ + struct dw_dma *dw = dev_id; + u32 status; + + dev_vdbg(dw->dma.dev, "interrupt: status=0x%x\n", + dma_readl(dw, STATUS_INT)); + + /* + * Just disable the interrupts. We'll turn them back on in the + * softirq handler. + */ + channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask); + channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask); + channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask); + + status = dma_readl(dw, STATUS_INT); + if (status) { + dev_err(dw->dma.dev, + "BUG: Unexpected interrupts pending: 0x%x\n", + status); + + /* Try to recover */ + channel_clear_bit(dw, MASK.XFER, (1 << 8) - 1); + channel_clear_bit(dw, MASK.BLOCK, (1 << 8) - 1); + channel_clear_bit(dw, MASK.SRC_TRAN, (1 << 8) - 1); + channel_clear_bit(dw, MASK.DST_TRAN, (1 << 8) - 1); + channel_clear_bit(dw, MASK.ERROR, (1 << 8) - 1); + } + + tasklet_schedule(&dw->tasklet); + + return IRQ_HANDLED; +} + +/*----------------------------------------------------------------------*/ + +static dma_cookie_t dwc_tx_submit(struct dma_async_tx_descriptor *tx) +{ + struct dw_desc *desc = txd_to_dw_desc(tx); + struct dw_dma_chan *dwc = to_dw_dma_chan(tx->chan); + dma_cookie_t cookie; + + spin_lock_bh(&dwc->lock); + cookie = dwc_assign_cookie(dwc, desc); + + /* + * REVISIT: We should attempt to chain as many descriptors as + * possible, perhaps even appending to those already submitted + * for DMA. But this is hard to do in a race-free manner. + */ + if (list_empty(&dwc->active_list)) { + dev_vdbg(&tx->chan->dev, "tx_submit: started %u\n", + desc->txd.cookie); + dwc_dostart(dwc, desc); + list_add_tail(&desc->desc_node, &dwc->active_list); + } else { + dev_vdbg(&tx->chan->dev, "tx_submit: queued %u\n", + desc->txd.cookie); + + list_add_tail(&desc->desc_node, &dwc->queue); + } + + spin_unlock_bh(&dwc->lock); + + return cookie; +} + +static struct dma_async_tx_descriptor * +dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, + size_t len, unsigned long flags) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_desc *desc; + struct dw_desc *first; + struct dw_desc *prev; + size_t xfer_count; + size_t offset; + unsigned int src_width; + unsigned int dst_width; + u32 ctllo; + + dev_vdbg(&chan->dev, "prep_dma_memcpy d0x%x s0x%x l0x%zx f0x%lx\n", + dest, src, len, flags); + + if (unlikely(!len)) { + dev_dbg(&chan->dev, "prep_dma_memcpy: length is zero!\n"); + return NULL; + } + + /* + * We can be a lot more clever here, but this should take care + * of the most common optimization. + */ + if (!((src | dest | len) & 3)) + src_width = dst_width = 2; + else if (!((src | dest | len) & 1)) + src_width = dst_width = 1; + else + src_width = dst_width = 0; + + ctllo = DWC_DEFAULT_CTLLO + | DWC_CTLL_DST_WIDTH(dst_width) + | DWC_CTLL_SRC_WIDTH(src_width) + | DWC_CTLL_DST_INC + | DWC_CTLL_SRC_INC + | DWC_CTLL_FC_M2M; + prev = first = NULL; + + for (offset = 0; offset < len; offset += xfer_count << src_width) { + xfer_count = min_t(size_t, (len - offset) >> src_width, + DWC_MAX_COUNT); + + desc = dwc_desc_get(dwc); + if (!desc) + goto err_desc_get; + + desc->lli.sar = src + offset; + desc->lli.dar = dest + offset; + desc->lli.ctllo = ctllo; + desc->lli.ctlhi = xfer_count; + + if (!first) { + first = desc; + } else { + prev->lli.llp = desc->txd.phys; + dma_sync_single_for_device(chan->dev.parent, + prev->txd.phys, sizeof(prev->lli), + DMA_TO_DEVICE); + list_add_tail(&desc->desc_node, + &first->txd.tx_list); + } + prev = desc; + } + + + if (flags & DMA_PREP_INTERRUPT) + /* Trigger interrupt after last block */ + prev->lli.ctllo |= DWC_CTLL_INT_EN; + + prev->lli.llp = 0; + dma_sync_single_for_device(chan->dev.parent, + prev->txd.phys, sizeof(prev->lli), + DMA_TO_DEVICE); + + first->txd.flags = flags; + first->len = len; + + return &first->txd; + +err_desc_get: + dwc_desc_put(dwc, first); + return NULL; +} + +static struct dma_async_tx_descriptor * +dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, + unsigned int sg_len, enum dma_data_direction direction, + unsigned long flags) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma_slave *dws = dwc->dws; + struct dw_desc *prev; + struct dw_desc *first; + u32 ctllo; + 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(&chan->dev, "prep_dma_slave\n"); + + if (unlikely(!dws || !sg_len)) + return NULL; + + reg_width = dws->slave.reg_width; + prev = first = NULL; + + sg_len = dma_map_sg(chan->dev.parent, sgl, sg_len, direction); + + switch (direction) { + case DMA_TO_DEVICE: + ctllo = (DWC_DEFAULT_CTLLO + | DWC_CTLL_DST_WIDTH(reg_width) + | DWC_CTLL_DST_FIX + | DWC_CTLL_SRC_INC + | DWC_CTLL_FC_M2P); + reg = dws->slave.tx_reg; + for_each_sg(sgl, sg, sg_len, i) { + struct dw_desc *desc; + u32 len; + u32 mem; + + desc = dwc_desc_get(dwc); + if (!desc) { + dev_err(&chan->dev, + "not enough descriptors available\n"); + goto err_desc_get; + } + + mem = sg_phys(sg); + len = sg_dma_len(sg); + mem_width = 2; + if (unlikely(mem & 3 || len & 3)) + mem_width = 0; + + desc->lli.sar = mem; + desc->lli.dar = reg; + desc->lli.ctllo = ctllo | DWC_CTLL_SRC_WIDTH(mem_width); + desc->lli.ctlhi = len >> mem_width; + + if (!first) { + first = desc; + } else { + prev->lli.llp = desc->txd.phys; + dma_sync_single_for_device(chan->dev.parent, + prev->txd.phys, + sizeof(prev->lli), + DMA_TO_DEVICE); + list_add_tail(&desc->desc_node, + &first->txd.tx_list); + } + prev = desc; + total_len += len; + } + break; + case DMA_FROM_DEVICE: + ctllo = (DWC_DEFAULT_CTLLO + | DWC_CTLL_SRC_WIDTH(reg_width) + | DWC_CTLL_DST_INC + | DWC_CTLL_SRC_FIX + | DWC_CTLL_FC_P2M); + + reg = dws->slave.rx_reg; + for_each_sg(sgl, sg, sg_len, i) { + struct dw_desc *desc; + u32 len; + u32 mem; + + desc = dwc_desc_get(dwc); + if (!desc) { + dev_err(&chan->dev, + "not enough descriptors available\n"); + goto err_desc_get; + } + + mem = sg_phys(sg); + len = sg_dma_len(sg); + mem_width = 2; + if (unlikely(mem & 3 || len & 3)) + mem_width = 0; + + desc->lli.sar = reg; + desc->lli.dar = mem; + desc->lli.ctllo = ctllo | DWC_CTLL_DST_WIDTH(mem_width); + desc->lli.ctlhi = len >> reg_width; + + if (!first) { + first = desc; + } else { + prev->lli.llp = desc->txd.phys; + dma_sync_single_for_device(chan->dev.parent, + prev->txd.phys, + sizeof(prev->lli), + DMA_TO_DEVICE); + list_add_tail(&desc->desc_node, + &first->txd.tx_list); + } + prev = desc; + total_len += len; + } + break; + default: + return NULL; + } + + if (flags & DMA_PREP_INTERRUPT) + /* Trigger interrupt after last block */ + prev->lli.ctllo |= DWC_CTLL_INT_EN; + + prev->lli.llp = 0; + dma_sync_single_for_device(chan->dev.parent, + prev->txd.phys, sizeof(prev->lli), + DMA_TO_DEVICE); + + first->len = total_len; + + return &first->txd; + +err_desc_get: + dwc_desc_put(dwc, first); + return NULL; +} + +static void dwc_terminate_all(struct dma_chan *chan) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma *dw = to_dw_dma(chan->device); + struct dw_desc *desc, *_desc; + LIST_HEAD(list); + + /* + * 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_bh(&dwc->lock); + + channel_clear_bit(dw, CH_EN, dwc->mask); + + while (dma_readl(dw, CH_EN) & dwc->mask) + cpu_relax(); + + /* active_list entries will end up before queued entries */ + list_splice_init(&dwc->queue, &list); + list_splice_init(&dwc->active_list, &list); + + spin_unlock_bh(&dwc->lock); + + /* Flush all pending and queued descriptors */ + list_for_each_entry_safe(desc, _desc, &list, desc_node) + dwc_descriptor_complete(dwc, desc); +} + +static enum dma_status +dwc_is_tx_complete(struct dma_chan *chan, + dma_cookie_t cookie, + dma_cookie_t *done, dma_cookie_t *used) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + dma_cookie_t last_used; + dma_cookie_t last_complete; + int ret; + + last_complete = dwc->completed; + last_used = chan->cookie; + + ret = dma_async_is_complete(cookie, last_complete, last_used); + if (ret != DMA_SUCCESS) { + dwc_scan_descriptors(to_dw_dma(chan->device), dwc); + + last_complete = dwc->completed; + last_used = chan->cookie; + + ret = dma_async_is_complete(cookie, last_complete, last_used); + } + + if (done) + *done = last_complete; + if (used) + *used = last_used; + + return ret; +} + +static void dwc_issue_pending(struct dma_chan *chan) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + + spin_lock_bh(&dwc->lock); + if (!list_empty(&dwc->queue)) + dwc_scan_descriptors(to_dw_dma(chan->device), dwc); + spin_unlock_bh(&dwc->lock); +} + +static int dwc_alloc_chan_resources(struct dma_chan *chan, + struct dma_client *client) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma *dw = to_dw_dma(chan->device); + struct dw_desc *desc; + struct dma_slave *slave; + struct dw_dma_slave *dws; + int i; + u32 cfghi; + u32 cfglo; + + dev_vdbg(&chan->dev, "alloc_chan_resources\n"); + + /* Channels doing slave DMA can only handle one client. */ + if (dwc->dws || client->slave) { + if (chan->client_count) + return -EBUSY; + } + + /* ASSERT: channel is idle */ + if (dma_readl(dw, CH_EN) & dwc->mask) { + dev_dbg(&chan->dev, "DMA channel not idle?\n"); + return -EIO; + } + + dwc->completed = chan->cookie = 1; + + cfghi = DWC_CFGH_FIFO_MODE; + cfglo = 0; + + slave = client->slave; + if (slave) { + /* + * We need controller-specific data to set up slave + * transfers. + */ + BUG_ON(!slave->dma_dev || slave->dma_dev != dw->dma.dev); + + dws = container_of(slave, struct dw_dma_slave, slave); + + dwc->dws = dws; + cfghi = dws->cfg_hi; + cfglo = dws->cfg_lo; + } else { + dwc->dws = NULL; + } + + channel_writel(dwc, CFG_LO, cfglo); + channel_writel(dwc, CFG_HI, cfghi); + + /* + * NOTE: some controllers may have additional features that we + * need to initialize here, like "scatter-gather" (which + * doesn't mean what you think it means), and status writeback. + */ + + spin_lock_bh(&dwc->lock); + i = dwc->descs_allocated; + while (dwc->descs_allocated < NR_DESCS_PER_CHANNEL) { + spin_unlock_bh(&dwc->lock); + + desc = kzalloc(sizeof(struct dw_desc), GFP_KERNEL); + if (!desc) { + dev_info(&chan->dev, + "only allocated %d descriptors\n", i); + spin_lock_bh(&dwc->lock); + break; + } + + dma_async_tx_descriptor_init(&desc->txd, chan); + desc->txd.tx_submit = dwc_tx_submit; + desc->txd.flags = DMA_CTRL_ACK; + INIT_LIST_HEAD(&desc->txd.tx_list); + desc->txd.phys = dma_map_single(chan->dev.parent, &desc->lli, + sizeof(desc->lli), DMA_TO_DEVICE); + dwc_desc_put(dwc, desc); + + spin_lock_bh(&dwc->lock); + i = ++dwc->descs_allocated; + } + + /* Enable interrupts */ + channel_set_bit(dw, MASK.XFER, dwc->mask); + channel_set_bit(dw, MASK.BLOCK, dwc->mask); + channel_set_bit(dw, MASK.ERROR, dwc->mask); + + spin_unlock_bh(&dwc->lock); + + dev_dbg(&chan->dev, + "alloc_chan_resources allocated %d descriptors\n", i); + + return i; +} + +static void dwc_free_chan_resources(struct dma_chan *chan) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma *dw = to_dw_dma(chan->device); + struct dw_desc *desc, *_desc; + LIST_HEAD(list); + + dev_dbg(&chan->dev, "free_chan_resources (descs allocated=%u)\n", + dwc->descs_allocated); + + /* ASSERT: channel is idle */ + BUG_ON(!list_empty(&dwc->active_list)); + BUG_ON(!list_empty(&dwc->queue)); + BUG_ON(dma_readl(to_dw_dma(chan->device), CH_EN) & dwc->mask); + + spin_lock_bh(&dwc->lock); + list_splice_init(&dwc->free_list, &list); + dwc->descs_allocated = 0; + dwc->dws = NULL; + + /* Disable interrupts */ + channel_clear_bit(dw, MASK.XFER, dwc->mask); + channel_clear_bit(dw, MASK.BLOCK, dwc->mask); + channel_clear_bit(dw, MASK.ERROR, dwc->mask); + + spin_unlock_bh(&dwc->lock); + + list_for_each_entry_safe(desc, _desc, &list, desc_node) { + dev_vdbg(&chan->dev, " freeing descriptor %p\n", desc); + dma_unmap_single(chan->dev.parent, desc->txd.phys, + sizeof(desc->lli), DMA_TO_DEVICE); + kfree(desc); + } + + dev_vdbg(&chan->dev, "free_chan_resources done\n"); +} + +/*----------------------------------------------------------------------*/ + +static void dw_dma_off(struct dw_dma *dw) +{ + dma_writel(dw, CFG, 0); + + channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask); + channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask); + channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask); + channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask); + channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask); + + while (dma_readl(dw, CFG) & DW_CFG_DMA_EN) + cpu_relax(); +} + +static int __init dw_probe(struct platform_device *pdev) +{ + struct dw_dma_platform_data *pdata; + struct resource *io; + struct dw_dma *dw; + size_t size; + int irq; + int err; + int i; + + pdata = pdev->dev.platform_data; + if (!pdata || pdata->nr_channels > DW_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 dw_dma); + size += pdata->nr_channels * sizeof(struct dw_dma_chan); + dw = kzalloc(size, GFP_KERNEL); + if (!dw) + return -ENOMEM; + + if (!request_mem_region(io->start, DW_REGLEN, pdev->dev.driver->name)) { + err = -EBUSY; + goto err_kfree; + } + + memset(dw, 0, sizeof *dw); + + dw->regs = ioremap(io->start, DW_REGLEN); + if (!dw->regs) { + err = -ENOMEM; + goto err_release_r; + } + + dw->clk = clk_get(&pdev->dev, "hclk"); + if (IS_ERR(dw->clk)) { + err = PTR_ERR(dw->clk); + goto err_clk; + } + clk_enable(dw->clk); + + /* force dma off, just in case */ + dw_dma_off(dw); + + err = request_irq(irq, dw_dma_interrupt, 0, "dw_dmac", dw); + if (err) + goto err_irq; + + platform_set_drvdata(pdev, dw); + + tasklet_init(&dw->tasklet, dw_dma_tasklet, (unsigned long)dw); + + dw->all_chan_mask = (1 << pdata->nr_channels) - 1; + + INIT_LIST_HEAD(&dw->dma.channels); + for (i = 0; i < pdata->nr_channels; i++, dw->dma.chancnt++) { + struct dw_dma_chan *dwc = &dw->chan[i]; + + dwc->chan.device = &dw->dma; + dwc->chan.cookie = dwc->completed = 1; + dwc->chan.chan_id = i; + list_add_tail(&dwc->chan.device_node, &dw->dma.channels); + + dwc->ch_regs = &__dw_regs(dw)->CHAN[i]; + spin_lock_init(&dwc->lock); + dwc->mask = 1 << i; + + INIT_LIST_HEAD(&dwc->active_list); + INIT_LIST_HEAD(&dwc->queue); + INIT_LIST_HEAD(&dwc->free_list); + + channel_clear_bit(dw, CH_EN, dwc->mask); + } + + /* Clear/disable all interrupts on all channels. */ + dma_writel(dw, CLEAR.XFER, dw->all_chan_mask); + dma_writel(dw, CLEAR.BLOCK, dw->all_chan_mask); + dma_writel(dw, CLEAR.SRC_TRAN, dw->all_chan_mask); + dma_writel(dw, CLEAR.DST_TRAN, dw->all_chan_mask); + dma_writel(dw, CLEAR.ERROR, dw->all_chan_mask); + + channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask); + channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask); + channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask); + channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask); + channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask); + + dma_cap_set(DMA_MEMCPY, dw->dma.cap_mask); + dma_cap_set(DMA_SLAVE, dw->dma.cap_mask); + dw->dma.dev = &pdev->dev; + dw->dma.device_alloc_chan_resources = dwc_alloc_chan_resources; + dw->dma.device_free_chan_resources = dwc_free_chan_resources; + + dw->dma.device_prep_dma_memcpy = dwc_prep_dma_memcpy; + + dw->dma.device_prep_slave_sg = dwc_prep_slave_sg; + dw->dma.device_terminate_all = dwc_terminate_all; + + dw->dma.device_is_tx_complete = dwc_is_tx_complete; + dw->dma.device_issue_pending = dwc_issue_pending; + + dma_writel(dw, CFG, DW_CFG_DMA_EN); + + printk(KERN_INFO "%s: DesignWare DMA Controller, %d channels\n", + pdev->dev.bus_id, dw->dma.chancnt); + + dma_async_device_register(&dw->dma); + + return 0; + +err_irq: + clk_disable(dw->clk); + clk_put(dw->clk); +err_clk: + iounmap(dw->regs); + dw->regs = NULL; +err_release_r: + release_resource(io); +err_kfree: + kfree(dw); + return err; +} + +static int __exit dw_remove(struct platform_device *pdev) +{ + struct dw_dma *dw = platform_get_drvdata(pdev); + struct dw_dma_chan *dwc, *_dwc; + struct resource *io; + + dw_dma_off(dw); + dma_async_device_unregister(&dw->dma); + + free_irq(platform_get_irq(pdev, 0), dw); + tasklet_kill(&dw->tasklet); + + list_for_each_entry_safe(dwc, _dwc, &dw->dma.channels, + chan.device_node) { + list_del(&dwc->chan.device_node); + channel_clear_bit(dw, CH_EN, dwc->mask); + } + + clk_disable(dw->clk); + clk_put(dw->clk); + + iounmap(dw->regs); + dw->regs = NULL; + + io = platform_get_resource(pdev, IORESOURCE_MEM, 0); + release_mem_region(io->start, DW_REGLEN); + + kfree(dw); + + return 0; +} + +static void dw_shutdown(struct platform_device *pdev) +{ + struct dw_dma *dw = platform_get_drvdata(pdev); + + dw_dma_off(platform_get_drvdata(pdev)); + clk_disable(dw->clk); +} + +static int dw_suspend_late(struct platform_device *pdev, pm_message_t mesg) +{ + struct dw_dma *dw = platform_get_drvdata(pdev); + + dw_dma_off(platform_get_drvdata(pdev)); + clk_disable(dw->clk); + return 0; +} + +static int dw_resume_early(struct platform_device *pdev) +{ + struct dw_dma *dw = platform_get_drvdata(pdev); + + clk_enable(dw->clk); + dma_writel(dw, CFG, DW_CFG_DMA_EN); + return 0; + +} + +static struct platform_driver dw_driver = { + .remove = __exit_p(dw_remove), + .shutdown = dw_shutdown, + .suspend_late = dw_suspend_late, + .resume_early = dw_resume_early, + .driver = { + .name = "dw_dmac", + }, +}; + +static int __init dw_init(void) +{ + return platform_driver_probe(&dw_driver, dw_probe); +} +module_init(dw_init); + +static void __exit dw_exit(void) +{ + platform_driver_unregister(&dw_driver); +} +module_exit(dw_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Synopsys DesignWare DMA Controller driver"); +MODULE_AUTHOR("Haavard Skinnemoen <haavard.skinnemoen@atmel.com>"); |