--- /dev/null
+/*
+ * 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>");
projects / kernel / kernel-generic.git / commitdiff