* [PATCH v4 5/6] dmaengine: Driver for the Synopsys DesignWare DMA controller
2008-06-26 13:23 ` [PATCH v4 4/6] dmaengine: Make DMA Engine menu visible for AVR32 users Haavard Skinnemoen
@ 2008-06-26 13:23 ` Haavard Skinnemoen
0 siblings, 0 replies; 3+ messages in thread
From: Haavard Skinnemoen @ 2008-06-26 13:23 UTC (permalink / raw)
To: Dan Williams, Pierre Ossman
Cc: linux-kernel, linux-embedded, kernel, shannon.nelson,
David Brownell, Haavard Skinnemoen
This adds a driver for the Synopsys DesignWare DMA controller (aka
DMACA on AVR32 systems.) This DMA controller can be found integrated
on the AT32AP7000 chip and is primarily meant for peripheral DMA
transfer, but can also be used for memory-to-memory transfers.
This patch is based on a driver from David Brownell which was based on
an older version of the DMA Engine framework. It also implements the
proposed extensions to the DMA Engine API for slave DMA operations.
The dmatest client shows no problems, but there may still be room for
improvement performance-wise. DMA slave transfer performance is
definitely "good enough"; reading 100 MiB from an SD card running at ~20
MHz yields ~7.2 MiB/s average transfer rate.
Full documentation for this controller can be found in the Synopsys
DW AHB DMAC Databook:
http://www.synopsys.com/designware/docs/iip/DW_ahb_dmac/latest/doc/dw_ahb_dmac_db.pdf
The controller has lots of implementation options, so it's usually a
good idea to check the data sheet of the chip it's intergrated on as
well. The AT32AP7000 data sheet can be found here:
http://www.atmel.com/dyn/products/datasheets.asp?family_id=682
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Changes since v3:
* Update to latest DMA engine and DMA slave APIs
* Embed the hw descriptor into the sw descriptor
* Clean up and update MODULE_DESCRIPTION, copyright date, etc.
Changes since v2:
* Dequeue all pending transfers in terminate_all()
* Rename dw_dmac.h -> dw_dmac_regs.h
* Define and use controller-specific dma_slave data
* Fix up a few outdated comments
* Define hardware registers as structs (doesn't generate better
code, unfortunately, but it looks nicer.)
* Get number of channels from platform_data instead of hardcoding it
based on CONFIG_WHATEVER_CPU.
* Give slave clients exclusive access to the channel
---
arch/avr32/mach-at32ap/at32ap700x.c | 26 +-
drivers/dma/Kconfig | 9 +
drivers/dma/Makefile | 1 +
drivers/dma/dw_dmac.c | 1105 ++++++++++++++++++++++++++++
drivers/dma/dw_dmac_regs.h | 224 ++++++
include/asm-avr32/arch-at32ap/at32ap700x.h | 16 +
include/linux/dw_dmac.h | 62 ++
7 files changed, 1430 insertions(+), 13 deletions(-)
create mode 100644 drivers/dma/dw_dmac.c
create mode 100644 drivers/dma/dw_dmac_regs.h
create mode 100644 include/linux/dw_dmac.h
diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c
index 0f24b4f..2b92047 100644
--- a/arch/avr32/mach-at32ap/at32ap700x.c
+++ b/arch/avr32/mach-at32ap/at32ap700x.c
@@ -599,6 +599,17 @@ static void __init genclk_init_parent(struct clk *clk)
clk->parent = parent;
}
+static struct dw_dma_platform_data dw_dmac0_data = {
+ .nr_channels = 3,
+};
+
+static struct resource dw_dmac0_resource[] = {
+ PBMEM(0xff200000),
+ IRQ(2),
+};
+DEFINE_DEV_DATA(dw_dmac, 0);
+DEV_CLK(hclk, dw_dmac0, hsb, 10);
+
/* --------------------------------------------------------------------
* System peripherals
* -------------------------------------------------------------------- */
@@ -705,17 +716,6 @@ static struct clk pico_clk = {
.users = 1,
};
-static struct resource dmaca0_resource[] = {
- {
- .start = 0xff200000,
- .end = 0xff20ffff,
- .flags = IORESOURCE_MEM,
- },
- IRQ(2),
-};
-DEFINE_DEV(dmaca, 0);
-DEV_CLK(hclk, dmaca0, hsb, 10);
-
/* --------------------------------------------------------------------
* HMATRIX
* -------------------------------------------------------------------- */
@@ -828,7 +828,7 @@ void __init at32_add_system_devices(void)
platform_device_register(&at32_eic0_device);
platform_device_register(&smc0_device);
platform_device_register(&pdc_device);
- platform_device_register(&dmaca0_device);
+ platform_device_register(&dw_dmac0_device);
platform_device_register(&at32_tcb0_device);
platform_device_register(&at32_tcb1_device);
@@ -1891,7 +1891,7 @@ struct clk *at32_clock_list[] = {
&smc0_mck,
&pdc_hclk,
&pdc_pclk,
- &dmaca0_hclk,
+ &dw_dmac0_hclk,
&pico_clk,
&pio0_mck,
&pio1_mck,
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 2ac09be..4fac4e3 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -37,6 +37,15 @@ config INTEL_IOP_ADMA
help
Enable support for the Intel(R) IOP Series RAID engines.
+config DW_DMAC
+ tristate "Synopsys DesignWare AHB DMA support"
+ depends on AVR32
+ select DMA_ENGINE
+ default y if CPU_AT32AP7000
+ help
+ Support the Synopsys DesignWare AHB DMA controller. This
+ can be integrated in chips such as the Atmel AT32ap7000.
+
config FSL_DMA
bool "Freescale MPC85xx/MPC83xx DMA support"
depends on PPC
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 2ff6d7f..beebae4 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -1,6 +1,7 @@
obj-$(CONFIG_DMA_ENGINE) += dmaengine.o
obj-$(CONFIG_NET_DMA) += iovlock.o
obj-$(CONFIG_INTEL_IOATDMA) += ioatdma.o
+obj-$(CONFIG_DW_DMAC) += dw_dmac.o
ioatdma-objs := ioat.o ioat_dma.o ioat_dca.o
obj-$(CONFIG_INTEL_IOP_ADMA) += iop-adma.o
obj-$(CONFIG_FSL_DMA) += fsldma.o
diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
new file mode 100644
index 0000000..e5389e1
--- /dev/null
+++ b/drivers/dma/dw_dmac.c
@@ -0,0 +1,1105 @@
+/*
+ * 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);
+
+ /*
+ * 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;
+
+ 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;
+
+ 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;
+ }
+ 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;
+ }
+ 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);
+
+ 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 (dma_chan_is_in_use(chan))
+ 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>");
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
new file mode 100644
index 0000000..119e65b
--- /dev/null
+++ b/drivers/dma/dw_dmac_regs.h
@@ -0,0 +1,224 @@
+/*
+ * Driver for the Synopsys DesignWare AHB DMA Controller
+ *
+ * Copyright (C) 2005-2007 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/dw_dmac.h>
+
+#define DW_DMA_MAX_NR_CHANNELS 8
+
+/*
+ * Redefine this macro to handle differences between 32- and 64-bit
+ * addressing, big vs. little endian, etc.
+ */
+#define DW_REG(name) u32 name; u32 __pad_##name
+
+/* Hardware register definitions. */
+struct dw_dma_chan_regs {
+ DW_REG(SAR); /* Source Address Register */
+ DW_REG(DAR); /* Destination Address Register */
+ DW_REG(LLP); /* Linked List Pointer */
+ u32 CTL_LO; /* Control Register Low */
+ u32 CTL_HI; /* Control Register High */
+ DW_REG(SSTAT);
+ DW_REG(DSTAT);
+ DW_REG(SSTATAR);
+ DW_REG(DSTATAR);
+ u32 CFG_LO; /* Configuration Register Low */
+ u32 CFG_HI; /* Configuration Register High */
+ DW_REG(SGR);
+ DW_REG(DSR);
+};
+
+struct dw_dma_irq_regs {
+ DW_REG(XFER);
+ DW_REG(BLOCK);
+ DW_REG(SRC_TRAN);
+ DW_REG(DST_TRAN);
+ DW_REG(ERROR);
+};
+
+struct dw_dma_regs {
+ /* per-channel registers */
+ struct dw_dma_chan_regs CHAN[DW_DMA_MAX_NR_CHANNELS];
+
+ /* irq handling */
+ struct dw_dma_irq_regs RAW; /* r */
+ struct dw_dma_irq_regs STATUS; /* r (raw & mask) */
+ struct dw_dma_irq_regs MASK; /* rw (set = irq enabled) */
+ struct dw_dma_irq_regs CLEAR; /* w (ack, affects "raw") */
+
+ DW_REG(STATUS_INT); /* r */
+
+ /* software handshaking */
+ DW_REG(REQ_SRC);
+ DW_REG(REQ_DST);
+ DW_REG(SGL_REQ_SRC);
+ DW_REG(SGL_REQ_DST);
+ DW_REG(LAST_SRC);
+ DW_REG(LAST_DST);
+
+ /* miscellaneous */
+ DW_REG(CFG);
+ DW_REG(CH_EN);
+ DW_REG(ID);
+ DW_REG(TEST);
+
+ /* optional encoded params, 0x3c8..0x3 */
+};
+
+/* Bitfields in CTL_LO */
+#define DWC_CTLL_INT_EN (1 << 0) /* irqs enabled? */
+#define DWC_CTLL_DST_WIDTH(n) ((n)<<1) /* bytes per element */
+#define DWC_CTLL_SRC_WIDTH(n) ((n)<<4)
+#define DWC_CTLL_DST_INC (0<<7) /* DAR update/not */
+#define DWC_CTLL_DST_DEC (1<<7)
+#define DWC_CTLL_DST_FIX (2<<7)
+#define DWC_CTLL_SRC_INC (0<<7) /* SAR update/not */
+#define DWC_CTLL_SRC_DEC (1<<9)
+#define DWC_CTLL_SRC_FIX (2<<9)
+#define DWC_CTLL_DST_MSIZE(n) ((n)<<11) /* burst, #elements */
+#define DWC_CTLL_SRC_MSIZE(n) ((n)<<14)
+#define DWC_CTLL_S_GATH_EN (1 << 17) /* src gather, !FIX */
+#define DWC_CTLL_D_SCAT_EN (1 << 18) /* dst scatter, !FIX */
+#define DWC_CTLL_FC_M2M (0 << 20) /* mem-to-mem */
+#define DWC_CTLL_FC_M2P (1 << 20) /* mem-to-periph */
+#define DWC_CTLL_FC_P2M (2 << 20) /* periph-to-mem */
+#define DWC_CTLL_FC_P2P (3 << 20) /* periph-to-periph */
+/* plus 4 transfer types for peripheral-as-flow-controller */
+#define DWC_CTLL_DMS(n) ((n)<<23) /* dst master select */
+#define DWC_CTLL_SMS(n) ((n)<<25) /* src master select */
+#define DWC_CTLL_LLP_D_EN (1 << 27) /* dest block chain */
+#define DWC_CTLL_LLP_S_EN (1 << 28) /* src block chain */
+
+/* Bitfields in CTL_HI */
+#define DWC_CTLH_DONE 0x00001000
+#define DWC_CTLH_BLOCK_TS_MASK 0x00000fff
+
+/* Bitfields in CFG_LO. Platform-configurable bits are in <linux/dw_dmac.h> */
+#define DWC_CFGL_CH_SUSP (1 << 8) /* pause xfer */
+#define DWC_CFGL_FIFO_EMPTY (1 << 9) /* pause xfer */
+#define DWC_CFGL_HS_DST (1 << 10) /* handshake w/dst */
+#define DWC_CFGL_HS_SRC (1 << 11) /* handshake w/src */
+#define DWC_CFGL_MAX_BURST(x) ((x) << 20)
+#define DWC_CFGL_RELOAD_SAR (1 << 30)
+#define DWC_CFGL_RELOAD_DAR (1 << 31)
+
+/* Bitfields in CFG_HI. Platform-configurable bits are in <linux/dw_dmac.h> */
+#define DWC_CFGH_DS_UPD_EN (1 << 5)
+#define DWC_CFGH_SS_UPD_EN (1 << 6)
+
+/* Bitfields in SGR */
+#define DWC_SGR_SGI(x) ((x) << 0)
+#define DWC_SGR_SGC(x) ((x) << 20)
+
+/* Bitfields in DSR */
+#define DWC_DSR_DSI(x) ((x) << 0)
+#define DWC_DSR_DSC(x) ((x) << 20)
+
+/* Bitfields in CFG */
+#define DW_CFG_DMA_EN (1 << 0)
+
+#define DW_REGLEN 0x400
+
+struct dw_dma_chan {
+ struct dma_chan chan;
+ void __iomem *ch_regs;
+ u8 mask;
+
+ spinlock_t lock;
+
+ /* these other elements are all protected by lock */
+ dma_cookie_t completed;
+ struct list_head active_list;
+ struct list_head queue;
+ struct list_head free_list;
+
+ struct dw_dma_slave *dws;
+
+ unsigned int descs_allocated;
+};
+
+static inline struct dw_dma_chan_regs __iomem *
+__dwc_regs(struct dw_dma_chan *dwc)
+{
+ return dwc->ch_regs;
+}
+
+#define channel_readl(dwc, name) \
+ __raw_readl(&(__dwc_regs(dwc)->name))
+#define channel_writel(dwc, name, val) \
+ __raw_writel((val), &(__dwc_regs(dwc)->name))
+
+static inline struct dw_dma_chan *to_dw_dma_chan(struct dma_chan *chan)
+{
+ return container_of(chan, struct dw_dma_chan, chan);
+}
+
+
+struct dw_dma {
+ struct dma_device dma;
+ void __iomem *regs;
+ struct tasklet_struct tasklet;
+ struct clk *clk;
+
+ u8 all_chan_mask;
+
+ struct dw_dma_chan chan[0];
+};
+
+static inline struct dw_dma_regs __iomem *__dw_regs(struct dw_dma *dw)
+{
+ return dw->regs;
+}
+
+#define dma_readl(dw, name) \
+ __raw_readl(&(__dw_regs(dw)->name))
+#define dma_writel(dw, name, val) \
+ __raw_writel((val), &(__dw_regs(dw)->name))
+
+#define channel_set_bit(dw, reg, mask) \
+ dma_writel(dw, reg, ((mask) << 8) | (mask))
+#define channel_clear_bit(dw, reg, mask) \
+ dma_writel(dw, reg, ((mask) << 8) | 0)
+
+static inline struct dw_dma *to_dw_dma(struct dma_device *ddev)
+{
+ return container_of(ddev, struct dw_dma, dma);
+}
+
+/* LLI == Linked List Item; a.k.a. DMA block descriptor */
+struct dw_lli {
+ /* values that are not changed by hardware */
+ dma_addr_t sar;
+ dma_addr_t dar;
+ dma_addr_t llp; /* chain to next lli */
+ u32 ctllo;
+ /* values that may get written back: */
+ u32 ctlhi;
+ /* sstat and dstat can snapshot peripheral register state.
+ * silicon config may discard either or both...
+ */
+ u32 sstat;
+ u32 dstat;
+};
+
+struct dw_desc {
+ /* FIRST values the hardware uses */
+ struct dw_lli lli;
+
+ /* THEN values for driver housekeeping */
+ struct list_head desc_node;
+ struct dma_async_tx_descriptor txd;
+};
+
+static inline struct dw_desc *
+txd_to_dw_desc(struct dma_async_tx_descriptor *txd)
+{
+ return container_of(txd, struct dw_desc, txd);
+}
diff --git a/include/asm-avr32/arch-at32ap/at32ap700x.h b/include/asm-avr32/arch-at32ap/at32ap700x.h
index 31e48b0..d18a305 100644
--- a/include/asm-avr32/arch-at32ap/at32ap700x.h
+++ b/include/asm-avr32/arch-at32ap/at32ap700x.h
@@ -30,4 +30,20 @@
#define GPIO_PIN_PD(N) (GPIO_PIOD_BASE + (N))
#define GPIO_PIN_PE(N) (GPIO_PIOE_BASE + (N))
+
+/*
+ * DMAC peripheral hardware handshaking interfaces, used with dw_dmac
+ */
+#define DMAC_MCI_RX 0
+#define DMAC_MCI_TX 1
+#define DMAC_DAC_TX 2
+#define DMAC_AC97_A_RX 3
+#define DMAC_AC97_A_TX 4
+#define DMAC_AC97_B_RX 5
+#define DMAC_AC97_B_TX 6
+#define DMAC_DMAREQ_0 7
+#define DMAC_DMAREQ_1 8
+#define DMAC_DMAREQ_2 9
+#define DMAC_DMAREQ_3 10
+
#endif /* __ASM_ARCH_AT32AP700X_H__ */
diff --git a/include/linux/dw_dmac.h b/include/linux/dw_dmac.h
new file mode 100644
index 0000000..04d217b
--- /dev/null
+++ b/include/linux/dw_dmac.h
@@ -0,0 +1,62 @@
+/*
+ * Driver for the Synopsys DesignWare DMA Controller (aka DMACA on
+ * AVR32 systems.)
+ *
+ * Copyright (C) 2007 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.
+ */
+#ifndef DW_DMAC_H
+#define DW_DMAC_H
+
+#include <linux/dmaengine.h>
+
+/**
+ * struct dw_dma_platform_data - Controller configuration parameters
+ * @nr_channels: Number of channels supported by hardware (max 8)
+ */
+struct dw_dma_platform_data {
+ unsigned int nr_channels;
+};
+
+/**
+ * struct dw_dma_slave - Controller-specific information about a slave
+ * @slave: Generic information about the slave
+ * @ctl_lo: Platform-specific initializer for the CTL_LO register
+ * @cfg_hi: Platform-specific initializer for the CFG_HI register
+ * @cfg_lo: Platform-specific initializer for the CFG_LO register
+ */
+struct dw_dma_slave {
+ struct dma_slave slave;
+ u32 cfg_hi;
+ u32 cfg_lo;
+};
+
+/* Platform-configurable bits in CFG_HI */
+#define DWC_CFGH_FCMODE (1 << 0)
+#define DWC_CFGH_FIFO_MODE (1 << 1)
+#define DWC_CFGH_PROTCTL(x) ((x) << 2)
+#define DWC_CFGH_SRC_PER(x) ((x) << 7)
+#define DWC_CFGH_DST_PER(x) ((x) << 11)
+
+/* Platform-configurable bits in CFG_LO */
+#define DWC_CFGL_PRIO(x) ((x) << 5) /* priority */
+#define DWC_CFGL_LOCK_CH_XFER (0 << 12) /* scope of LOCK_CH */
+#define DWC_CFGL_LOCK_CH_BLOCK (1 << 12)
+#define DWC_CFGL_LOCK_CH_XACT (2 << 12)
+#define DWC_CFGL_LOCK_BUS_XFER (0 << 14) /* scope of LOCK_BUS */
+#define DWC_CFGL_LOCK_BUS_BLOCK (1 << 14)
+#define DWC_CFGL_LOCK_BUS_XACT (2 << 14)
+#define DWC_CFGL_LOCK_CH (1 << 15) /* channel lockout */
+#define DWC_CFGL_LOCK_BUS (1 << 16) /* busmaster lockout */
+#define DWC_CFGL_HS_DST_POL (1 << 18) /* dst handshake active low */
+#define DWC_CFGL_HS_SRC_POL (1 << 19) /* src handshake active low */
+
+static inline struct dw_dma_slave *to_dw_dma_slave(struct dma_slave *slave)
+{
+ return container_of(slave, struct dw_dma_slave, slave);
+}
+
+#endif /* DW_DMAC_H */
--
1.5.5.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* RE: [PATCH v4 5/6] dmaengine: Driver for the Synopsys DesignWare DMA controller
[not found] <f12847240806270224h696e78a1v4a1aa6a87fb4a171@mail.gmail.com>
@ 2008-07-04 15:33 ` Sosnowski, Maciej
2008-07-04 16:10 ` Haavard Skinnemoen
0 siblings, 1 reply; 3+ messages in thread
From: Sosnowski, Maciej @ 2008-07-04 15:33 UTC (permalink / raw)
To: haavard.skinnemoen
Cc: Williams, Dan J, drzeus-list, lkml, linux-embedded, kernel,
Nelson, Shannon, david-b
> ---------- Original message ----------
> From: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
> Date: Jun 26, 2008 3:23 PM
> Subject: [PATCH v4 5/6] dmaengine: Driver for the Synopsys DesignWare
> DMA controller
> To: Dan Williams <dan.j.williams@intel.com>, Pierre Ossman
> <drzeus-list@drzeus.cx>
> Cc: linux-kernel@vger.kernel.org, linux-embedded@vger.kernel.org,
> kernel@avr32linux.org, shannon.nelson@intel.com, David Brownell
> <david-b@pacbell.net>, Haavard Skinnemoen
> <haavard.skinnemoen@atmel.com>
>
>
> This adds a driver for the Synopsys DesignWare DMA controller (aka
> DMACA on AVR32 systems.) This DMA controller can be found integrated
> on the AT32AP7000 chip and is primarily meant for peripheral DMA
> transfer, but can also be used for memory-to-memory transfers.
>
> This patch is based on a driver from David Brownell which was based on
> an older version of the DMA Engine framework. It also implements the
> proposed extensions to the DMA Engine API for slave DMA operations.
>
> The dmatest client shows no problems, but there may still be room for
> improvement performance-wise. DMA slave transfer performance is
> definitely "good enough"; reading 100 MiB from an SD card running at
~20
> MHz yields ~7.2 MiB/s average transfer rate.
>
> Full documentation for this controller can be found in the Synopsys
> DW AHB DMAC Databook:
>
>
http://www.synopsys.com/designware/docs/iip/DW_ahb_dmac/latest/doc/dw_ah
b_dmac_db.pdf
>
> The controller has lots of implementation options, so it's usually a
> good idea to check the data sheet of the chip it's intergrated on as
> well. The AT32AP7000 data sheet can be found here:
>
> http://www.atmel.com/dyn/products/datasheets.asp?family_id=682
>
> Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
>
> Changes since v3:
> * Update to latest DMA engine and DMA slave APIs
> * Embed the hw descriptor into the sw descriptor
> * Clean up and update MODULE_DESCRIPTION, copyright date, etc.
>
> Changes since v2:
> * Dequeue all pending transfers in terminate_all()
> * Rename dw_dmac.h -> dw_dmac_regs.h
> * Define and use controller-specific dma_slave data
> * Fix up a few outdated comments
> * Define hardware registers as structs (doesn't generate better
> code, unfortunately, but it looks nicer.)
> * Get number of channels from platform_data instead of hardcoding it
> based on CONFIG_WHATEVER_CPU.
> * Give slave clients exclusive access to the channel
Coulpe of questions and comments from my side below.
Apart from that the code looks fine to me.
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
> ---
> arch/avr32/mach-at32ap/at32ap700x.c | 26 +-
> drivers/dma/Kconfig | 9 +
> drivers/dma/Makefile | 1 +
> drivers/dma/dw_dmac.c | 1105
> ++++++++++++++++++++++++++++ drivers/dma/dw_dmac_regs.h
|
> 224 ++++++ include/asm-avr32/arch-at32ap/at32ap700x.h | 16 +
> include/linux/dw_dmac.h | 62 ++
> 7 files changed, 1430 insertions(+), 13 deletions(-)
> create mode 100644 drivers/dma/dw_dmac.c
> create mode 100644 drivers/dma/dw_dmac_regs.h
> create mode 100644 include/linux/dw_dmac.h
>
> diff --git a/arch/avr32/mach-at32ap/at32ap700x.c
> b/arch/avr32/mach-at32ap/at32ap700x.c
> index 0f24b4f..2b92047 100644
> --- a/arch/avr32/mach-at32ap/at32ap700x.c
> +++ b/arch/avr32/mach-at32ap/at32ap700x.c
> @@ -599,6 +599,17 @@ static void __init genclk_init_parent(struct clk
*clk)
> clk->parent = parent;
> }
>
> +static struct dw_dma_platform_data dw_dmac0_data = {
> + .nr_channels = 3,
> +};
> +
> +static struct resource dw_dmac0_resource[] = {
> + PBMEM(0xff200000),
> + IRQ(2),
> +};
> +DEFINE_DEV_DATA(dw_dmac, 0);
> +DEV_CLK(hclk, dw_dmac0, hsb, 10);
> +
> /*
--------------------------------------------------------------------
> * System peripherals
> *
-------------------------------------------------------------------- */
> @@ -705,17 +716,6 @@ static struct clk pico_clk = {
> .users = 1,
> };
>
> -static struct resource dmaca0_resource[] = {
> - {
> - .start = 0xff200000,
> - .end = 0xff20ffff,
> - .flags = IORESOURCE_MEM,
> - },
> - IRQ(2),
> -};
> -DEFINE_DEV(dmaca, 0);
> -DEV_CLK(hclk, dmaca0, hsb, 10);
> -
> /*
--------------------------------------------------------------------
> * HMATRIX
> *
-------------------------------------------------------------------- */
> @@ -828,7 +828,7 @@ void __init at32_add_system_devices(void)
> platform_device_register(&at32_eic0_device);
> platform_device_register(&smc0_device);
> platform_device_register(&pdc_device);
> - platform_device_register(&dmaca0_device);
> + platform_device_register(&dw_dmac0_device);
>
> platform_device_register(&at32_tcb0_device);
> platform_device_register(&at32_tcb1_device);
> @@ -1891,7 +1891,7 @@ struct clk *at32_clock_list[] = {
> &smc0_mck,
> &pdc_hclk,
> &pdc_pclk,
> - &dmaca0_hclk,
> + &dw_dmac0_hclk,
> &pico_clk,
> &pio0_mck,
> &pio1_mck,
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index 2ac09be..4fac4e3 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -37,6 +37,15 @@ config INTEL_IOP_ADMA
> help
> Enable support for the Intel(R) IOP Series RAID engines.
>
> +config DW_DMAC
> + tristate "Synopsys DesignWare AHB DMA support"
> + depends on AVR32
> + select DMA_ENGINE
> + default y if CPU_AT32AP7000
> + help
> + Support the Synopsys DesignWare AHB DMA controller. This
> + can be integrated in chips such as the Atmel AT32ap7000.
> +
> config FSL_DMA
> bool "Freescale MPC85xx/MPC83xx DMA support"
> depends on PPC
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index 2ff6d7f..beebae4 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -1,6 +1,7 @@
> obj-$(CONFIG_DMA_ENGINE) += dmaengine.o
> obj-$(CONFIG_NET_DMA) += iovlock.o
> obj-$(CONFIG_INTEL_IOATDMA) += ioatdma.o
> +obj-$(CONFIG_DW_DMAC) += dw_dmac.o
> ioatdma-objs := ioat.o ioat_dma.o ioat_dca.o
> obj-$(CONFIG_INTEL_IOP_ADMA) += iop-adma.o
> obj-$(CONFIG_FSL_DMA) += fsldma.o
> diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
> new file mode 100644
> index 0000000..e5389e1
> --- /dev/null
> +++ b/drivers/dma/dw_dmac.c
> @@ -0,0 +1,1105 @@
> +/*
> + * 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;
Should not at this point an error status be returned
so that it can be handled accordingly by dwc_dostart() caller?
> + }
> +
> + 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);
> +
> + /*
> + * 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);
Here it looks like the maximum xfer_count value can change - it depends
on src_width,
so it may be different for different transactions.
Is that ok?
> +
> + 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;
> +
> + 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;
> +
> + 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;
> + }
> + 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;
> + }
> + 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);
> +
> + 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 (dma_chan_is_in_use(chan))
> + 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;
> +}
This driver does not perform any self-test during initialization.
What about adding some initial HW checking?
> +
> +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>");
> diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
> new file mode 100644
> index 0000000..119e65b
> --- /dev/null
> +++ b/drivers/dma/dw_dmac_regs.h
> @@ -0,0 +1,224 @@
> +/*
> + * Driver for the Synopsys DesignWare AHB DMA Controller
> + *
> + * Copyright (C) 2005-2007 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/dw_dmac.h>
> +
> +#define DW_DMA_MAX_NR_CHANNELS 8
> +
> +/*
> + * Redefine this macro to handle differences between 32- and 64-bit
> + * addressing, big vs. little endian, etc.
> + */
> +#define DW_REG(name) u32 name; u32 __pad_##name
> +
> +/* Hardware register definitions. */
> +struct dw_dma_chan_regs {
> + DW_REG(SAR); /* Source Address Register */
> + DW_REG(DAR); /* Destination Address Register */
> + DW_REG(LLP); /* Linked List Pointer */
> + u32 CTL_LO; /* Control Register Low */
> + u32 CTL_HI; /* Control Register High */
> + DW_REG(SSTAT);
> + DW_REG(DSTAT);
> + DW_REG(SSTATAR);
> + DW_REG(DSTATAR);
> + u32 CFG_LO; /* Configuration Register Low */
> + u32 CFG_HI; /* Configuration Register High */
> + DW_REG(SGR);
> + DW_REG(DSR);
> +};
> +
> +struct dw_dma_irq_regs {
> + DW_REG(XFER);
> + DW_REG(BLOCK);
> + DW_REG(SRC_TRAN);
> + DW_REG(DST_TRAN);
> + DW_REG(ERROR);
> +};
> +
> +struct dw_dma_regs {
> + /* per-channel registers */
> + struct dw_dma_chan_regs CHAN[DW_DMA_MAX_NR_CHANNELS];
> +
> + /* irq handling */
> + struct dw_dma_irq_regs RAW; /* r */
> + struct dw_dma_irq_regs STATUS; /* r (raw & mask) */
> + struct dw_dma_irq_regs MASK; /* rw (set = irq
enabled) */
> + struct dw_dma_irq_regs CLEAR; /* w (ack, affects
"raw") */
> +
> + DW_REG(STATUS_INT); /* r */
> +
> + /* software handshaking */
> + DW_REG(REQ_SRC);
> + DW_REG(REQ_DST);
> + DW_REG(SGL_REQ_SRC);
> + DW_REG(SGL_REQ_DST);
> + DW_REG(LAST_SRC);
> + DW_REG(LAST_DST);
> +
> + /* miscellaneous */
> + DW_REG(CFG);
> + DW_REG(CH_EN);
> + DW_REG(ID);
> + DW_REG(TEST);
> +
> + /* optional encoded params, 0x3c8..0x3 */
> +};
> +
> +/* Bitfields in CTL_LO */
> +#define DWC_CTLL_INT_EN (1 << 0) /* irqs
enabled? */
> +#define DWC_CTLL_DST_WIDTH(n) ((n)<<1) /* bytes per element
*/
> +#define DWC_CTLL_SRC_WIDTH(n) ((n)<<4)
> +#define DWC_CTLL_DST_INC (0<<7) /* DAR update/not */
> +#define DWC_CTLL_DST_DEC (1<<7)
> +#define DWC_CTLL_DST_FIX (2<<7)
> +#define DWC_CTLL_SRC_INC (0<<7) /* SAR update/not */
> +#define DWC_CTLL_SRC_DEC (1<<9)
> +#define DWC_CTLL_SRC_FIX (2<<9)
> +#define DWC_CTLL_DST_MSIZE(n) ((n)<<11) /* burst, #elements */
> +#define DWC_CTLL_SRC_MSIZE(n) ((n)<<14)
> +#define DWC_CTLL_S_GATH_EN (1 << 17) /* src gather, !FIX */
> +#define DWC_CTLL_D_SCAT_EN (1 << 18) /* dst scatter, !FIX
*/
> +#define DWC_CTLL_FC_M2M (0 << 20) /* mem-to-mem
*/
> +#define DWC_CTLL_FC_M2P (1 << 20) /*
mem-to-periph */
> +#define DWC_CTLL_FC_P2M (2 << 20) /*
periph-to-mem */
> +#define DWC_CTLL_FC_P2P (3 << 20) /*
periph-to-periph */
> +/* plus 4 transfer types for peripheral-as-flow-controller */
> +#define DWC_CTLL_DMS(n) ((n)<<23) /* dst master
select
> */ +#define DWC_CTLL_SMS(n) ((n)<<25) /* src
master
> select */ +#define DWC_CTLL_LLP_D_EN (1 << 27) /* dest
block chain
> */ +#define DWC_CTLL_LLP_S_EN (1 << 28) /* src block chain
*/
> +
> +/* Bitfields in CTL_HI */
> +#define DWC_CTLH_DONE 0x00001000
> +#define DWC_CTLH_BLOCK_TS_MASK 0x00000fff
> +
> +/* Bitfields in CFG_LO. Platform-configurable bits are in
<linux/dw_dmac.h>
> */ +#define DWC_CFGL_CH_SUSP (1 << 8) /* pause xfer */
> +#define DWC_CFGL_FIFO_EMPTY (1 << 9) /* pause xfer */
> +#define DWC_CFGL_HS_DST (1 << 10) /* handshake
w/dst */
> +#define DWC_CFGL_HS_SRC (1 << 11) /* handshake
w/src */
> +#define DWC_CFGL_MAX_BURST(x) ((x) << 20)
> +#define DWC_CFGL_RELOAD_SAR (1 << 30)
> +#define DWC_CFGL_RELOAD_DAR (1 << 31)
> +
> +/* Bitfields in CFG_HI. Platform-configurable bits are in
<linux/dw_dmac.h>
> */ +#define DWC_CFGH_DS_UPD_EN (1 << 5)
> +#define DWC_CFGH_SS_UPD_EN (1 << 6)
> +
> +/* Bitfields in SGR */
> +#define DWC_SGR_SGI(x) ((x) << 0)
> +#define DWC_SGR_SGC(x) ((x) << 20)
> +
> +/* Bitfields in DSR */
> +#define DWC_DSR_DSI(x) ((x) << 0)
> +#define DWC_DSR_DSC(x) ((x) << 20)
> +
> +/* Bitfields in CFG */
> +#define DW_CFG_DMA_EN (1 << 0)
> +
> +#define DW_REGLEN 0x400
> +
> +struct dw_dma_chan {
> + struct dma_chan chan;
> + void __iomem *ch_regs;
> + u8 mask;
> +
> + spinlock_t lock;
> +
> + /* these other elements are all protected by lock */
> + dma_cookie_t completed;
> + struct list_head active_list;
> + struct list_head queue;
> + struct list_head free_list;
> +
> + struct dw_dma_slave *dws;
> +
> + unsigned int descs_allocated;
> +};
> +
> +static inline struct dw_dma_chan_regs __iomem *
> +__dwc_regs(struct dw_dma_chan *dwc)
> +{
> + return dwc->ch_regs;
> +}
> +
> +#define channel_readl(dwc, name) \
> + __raw_readl(&(__dwc_regs(dwc)->name))
> +#define channel_writel(dwc, name, val) \
> + __raw_writel((val), &(__dwc_regs(dwc)->name))
> +
> +static inline struct dw_dma_chan *to_dw_dma_chan(struct dma_chan
*chan)
> +{
> + return container_of(chan, struct dw_dma_chan, chan);
> +}
> +
> +
> +struct dw_dma {
> + struct dma_device dma;
> + void __iomem *regs;
> + struct tasklet_struct tasklet;
> + struct clk *clk;
> +
> + u8 all_chan_mask;
> +
> + struct dw_dma_chan chan[0];
> +};
> +
> +static inline struct dw_dma_regs __iomem *__dw_regs(struct dw_dma
*dw)
> +{
> + return dw->regs;
> +}
> +
> +#define dma_readl(dw, name) \
> + __raw_readl(&(__dw_regs(dw)->name))
> +#define dma_writel(dw, name, val) \
> + __raw_writel((val), &(__dw_regs(dw)->name))
> +
> +#define channel_set_bit(dw, reg, mask) \
> + dma_writel(dw, reg, ((mask) << 8) | (mask))
> +#define channel_clear_bit(dw, reg, mask) \
> + dma_writel(dw, reg, ((mask) << 8) | 0)
> +
> +static inline struct dw_dma *to_dw_dma(struct dma_device *ddev)
> +{
> + return container_of(ddev, struct dw_dma, dma);
> +}
> +
> +/* LLI == Linked List Item; a.k.a. DMA block descriptor */
> +struct dw_lli {
> + /* values that are not changed by hardware */
> + dma_addr_t sar;
> + dma_addr_t dar;
> + dma_addr_t llp; /* chain to next lli */
> + u32 ctllo;
> + /* values that may get written back: */
> + u32 ctlhi;
> + /* sstat and dstat can snapshot peripheral register state.
> + * silicon config may discard either or both...
> + */
> + u32 sstat;
> + u32 dstat;
> +};
> +
> +struct dw_desc {
> + /* FIRST values the hardware uses */
> + struct dw_lli lli;
> +
> + /* THEN values for driver housekeeping */
> + struct list_head desc_node;
> + struct dma_async_tx_descriptor txd;
> +};
> +
> +static inline struct dw_desc *
> +txd_to_dw_desc(struct dma_async_tx_descriptor *txd)
> +{
> + return container_of(txd, struct dw_desc, txd);
> +}
> diff --git a/include/asm-avr32/arch-at32ap/at32ap700x.h
> b/include/asm-avr32/arch-at32ap/at32ap700x.h
> index 31e48b0..d18a305 100644
> --- a/include/asm-avr32/arch-at32ap/at32ap700x.h
> +++ b/include/asm-avr32/arch-at32ap/at32ap700x.h
> @@ -30,4 +30,20 @@
> #define GPIO_PIN_PD(N) (GPIO_PIOD_BASE + (N))
> #define GPIO_PIN_PE(N) (GPIO_PIOE_BASE + (N))
>
> +
> +/*
> + * DMAC peripheral hardware handshaking interfaces, used with dw_dmac
> + */
> +#define DMAC_MCI_RX 0
> +#define DMAC_MCI_TX 1
> +#define DMAC_DAC_TX 2
> +#define DMAC_AC97_A_RX 3
> +#define DMAC_AC97_A_TX 4
> +#define DMAC_AC97_B_RX 5
> +#define DMAC_AC97_B_TX 6
> +#define DMAC_DMAREQ_0 7
> +#define DMAC_DMAREQ_1 8
> +#define DMAC_DMAREQ_2 9
> +#define DMAC_DMAREQ_3 10
> +
> #endif /* __ASM_ARCH_AT32AP700X_H__ */
> diff --git a/include/linux/dw_dmac.h b/include/linux/dw_dmac.h
> new file mode 100644
> index 0000000..04d217b
> --- /dev/null
> +++ b/include/linux/dw_dmac.h
> @@ -0,0 +1,62 @@
> +/*
> + * Driver for the Synopsys DesignWare DMA Controller (aka DMACA on
> + * AVR32 systems.)
> + *
> + * Copyright (C) 2007 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.
> + */
> +#ifndef DW_DMAC_H
> +#define DW_DMAC_H
> +
> +#include <linux/dmaengine.h>
> +
> +/**
> + * struct dw_dma_platform_data - Controller configuration parameters
> + * @nr_channels: Number of channels supported by hardware (max 8)
> + */
> +struct dw_dma_platform_data {
> + unsigned int nr_channels;
> +};
> +
> +/**
> + * struct dw_dma_slave - Controller-specific information about a
slave
> + * @slave: Generic information about the slave
> + * @ctl_lo: Platform-specific initializer for the CTL_LO register
> + * @cfg_hi: Platform-specific initializer for the CFG_HI register
> + * @cfg_lo: Platform-specific initializer for the CFG_LO register
> + */
> +struct dw_dma_slave {
> + struct dma_slave slave;
> + u32 cfg_hi;
> + u32 cfg_lo;
> +};
> +
> +/* Platform-configurable bits in CFG_HI */
> +#define DWC_CFGH_FCMODE (1 << 0)
> +#define DWC_CFGH_FIFO_MODE (1 << 1)
> +#define DWC_CFGH_PROTCTL(x) ((x) << 2)
> +#define DWC_CFGH_SRC_PER(x) ((x) << 7)
> +#define DWC_CFGH_DST_PER(x) ((x) << 11)
> +
> +/* Platform-configurable bits in CFG_LO */
> +#define DWC_CFGL_PRIO(x) ((x) << 5) /* priority */
> +#define DWC_CFGL_LOCK_CH_XFER (0 << 12) /* scope of LOCK_CH */
> +#define DWC_CFGL_LOCK_CH_BLOCK (1 << 12)
> +#define DWC_CFGL_LOCK_CH_XACT (2 << 12)
> +#define DWC_CFGL_LOCK_BUS_XFER (0 << 14) /* scope of LOCK_BUS
*/
> +#define DWC_CFGL_LOCK_BUS_BLOCK (1 << 14)
> +#define DWC_CFGL_LOCK_BUS_XACT (2 << 14)
> +#define DWC_CFGL_LOCK_CH (1 << 15) /* channel lockout */
> +#define DWC_CFGL_LOCK_BUS (1 << 16) /* busmaster lockout
*/
> +#define DWC_CFGL_HS_DST_POL (1 << 18) /* dst handshake
active low */
> +#define DWC_CFGL_HS_SRC_POL (1 << 19) /* src handshake
active low */
> +
> +static inline struct dw_dma_slave *to_dw_dma_slave(struct dma_slave
*slave)
> +{
> + return container_of(slave, struct dw_dma_slave, slave);
> +}
> +
> +#endif /* DW_DMAC_H */
> --
> 1.5.5.4
Regards,
Maciej
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v4 5/6] dmaengine: Driver for the Synopsys DesignWare DMA controller
2008-07-04 15:33 ` [PATCH v4 5/6] dmaengine: Driver for the Synopsys DesignWare DMA controller Sosnowski, Maciej
@ 2008-07-04 16:10 ` Haavard Skinnemoen
0 siblings, 0 replies; 3+ messages in thread
From: Haavard Skinnemoen @ 2008-07-04 16:10 UTC (permalink / raw)
To: Sosnowski, Maciej
Cc: Williams, Dan J, drzeus-list, lkml, linux-embedded, kernel,
Nelson, Shannon, david-b
On Fri, 4 Jul 2008 16:33:53 +0100
"Sosnowski, Maciej" <maciej.sosnowski@intel.com> wrote:
> Coulpe of questions and comments from my side below.
> Apart from that the code looks fine to me.
>
> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Thanks a lot for reviewing!
> > +/* 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;
>
> Should not at this point an error status be returned
> so that it can be handled accordingly by dwc_dostart() caller?
There's not a whole lot of meaningful things to do for the caller. It
should never happen in the first place, but if the channel _is_ active
at this point, we will eventually get an xfer complete interrupt when
the currently pending transfers are done. The descriptors have already
been added to the list, so the driver should recover from this kind of
bug automatically.
I've never actually triggered this code, so I can't really say for
certain that it works, but at least in theory it makes much more sense
to fix things up when the channel eventually becomes idle.
> > + 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);
>
> Here it looks like the maximum xfer_count value can change - it depends
> on src_width,
> so it may be different for different transactions.
> Is that ok?
Yes, the maximum tranfer count is defined as the maximum number of
source transactions on the bus. So if the controller is set up to do 32
bits at a time on the source side, the maximum transfer _length_ is
four times the maximum transfer _count_.
The value written to the descriptor is also a transaction count, not a
byte count.
> This driver does not perform any self-test during initialization.
> What about adding some initial HW checking?
I'm not sure if it makes a lot of sense -- this device is typically
integrated on the same silicon as the CPU, so if there are any issues
with the DMA controller, they should be caught during production
testing.
I'm using the dmatest module for validating the driver, so I feel the
self-test stuff becomes somewhat redundant.
Haavard
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2008-07-04 16:10 UTC | newest]
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[not found] <f12847240806270224h696e78a1v4a1aa6a87fb4a171@mail.gmail.com>
2008-07-04 15:33 ` [PATCH v4 5/6] dmaengine: Driver for the Synopsys DesignWare DMA controller Sosnowski, Maciej
2008-07-04 16:10 ` Haavard Skinnemoen
2008-06-26 13:23 [PATCH v4 0/6] dmaengine/mmc: DMA slave interface and two new drivers Haavard Skinnemoen
2008-06-26 13:23 ` [PATCH v4 1/6] dmaengine: Add dma_client parameter to device_alloc_chan_resources Haavard Skinnemoen
2008-06-26 13:23 ` [PATCH v4 2/6] dmaengine: Add dma_chan_is_in_use() function Haavard Skinnemoen
2008-06-26 13:23 ` [PATCH v4 3/6] dmaengine: Add slave DMA interface Haavard Skinnemoen
2008-06-26 13:23 ` [PATCH v4 4/6] dmaengine: Make DMA Engine menu visible for AVR32 users Haavard Skinnemoen
2008-06-26 13:23 ` [PATCH v4 5/6] dmaengine: Driver for the Synopsys DesignWare DMA controller Haavard Skinnemoen
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