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Subject[PATCH 2/2] dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver
Date
This adds external DMA controller driver implemented in Socionext
UniPhier SoCs. This driver supports DMA_MEMCPY and DMA_SLAVE modes.

Since this driver does not support the the way to transfer size
unaligned to burst width, 'src_maxburst' or 'dst_maxburst' of
dma_slave_config must be 1 to transfer arbitrary size,

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
---
drivers/dma/Kconfig | 11 +
drivers/dma/Makefile | 1 +
drivers/dma/uniphier-xdmac.c | 620 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 632 insertions(+)
create mode 100644 drivers/dma/uniphier-xdmac.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 7af874b..2d1cb5e 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -608,6 +608,17 @@ config UNIPHIER_MDMAC
UniPhier platform. This DMA controller is used as the external
DMA engine of the SD/eMMC controllers of the LD4, Pro4, sLD8 SoCs.

+config UNIPHIER_XDMAC
+ tristate "UniPhier XDMAC support"
+ depends on ARCH_UNIPHIER || COMPILE_TEST
+ depends on OF
+ select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
+ help
+ Enable support for the XDMAC (external DMA controller) on the
+ UniPhier platform. This DMA controller can transfer data from
+ memory to memory, memory to peripheral and peripheral to memory.
+
config XGENE_DMA
tristate "APM X-Gene DMA support"
depends on ARCH_XGENE || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index f5ce866..6452468 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -72,6 +72,7 @@ obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
obj-$(CONFIG_TEGRA210_ADMA) += tegra210-adma.o
obj-$(CONFIG_TIMB_DMA) += timb_dma.o
obj-$(CONFIG_UNIPHIER_MDMAC) += uniphier-mdmac.o
+obj-$(CONFIG_UNIPHIER_XDMAC) += uniphier-xdmac.o
obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
obj-$(CONFIG_ZX_DMA) += zx_dma.o
obj-$(CONFIG_ST_FDMA) += st_fdma.o
diff --git a/drivers/dma/uniphier-xdmac.c b/drivers/dma/uniphier-xdmac.c
new file mode 100644
index 00000000..b21aa6a
--- /dev/null
+++ b/drivers/dma/uniphier-xdmac.c
@@ -0,0 +1,620 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * External DMA controller driver for UniPhier SoCs
+ * Copyright 2019 Socionext Inc.
+ * Author: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/bitfield.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+
+#include "dmaengine.h"
+#include "virt-dma.h"
+
+#define XDMAC_CH_WIDTH 0x100
+
+#define XDMAC_TFA 0x08
+#define XDMAC_TFA_MCNT_MASK GENMASK(23, 16)
+#define XDMAC_TFA_MASK GENMASK(5, 0)
+#define XDMAC_SADM 0x10
+#define XDMAC_SADM_STW_MASK GENMASK(25, 24)
+#define XDMAC_SADM_SAM BIT(4)
+#define XDMAC_SADM_SAM_FIXED XDMAC_SADM_SAM
+#define XDMAC_SADM_SAM_INC 0
+#define XDMAC_DADM 0x14
+#define XDMAC_DADM_DTW_MASK XDMAC_SADM_STW_MASK
+#define XDMAC_DADM_DAM XDMAC_SADM_SAM
+#define XDMAC_DADM_DAM_FIXED XDMAC_SADM_SAM_FIXED
+#define XDMAC_DADM_DAM_INC XDMAC_SADM_SAM_INC
+#define XDMAC_EXSAD 0x18
+#define XDMAC_EXDAD 0x1c
+#define XDMAC_SAD 0x20
+#define XDMAC_DAD 0x24
+#define XDMAC_ITS 0x28
+#define XDMAC_ITS_MASK GENMASK(25, 0)
+#define XDMAC_TNUM 0x2c
+#define XDMAC_TNUM_MASK GENMASK(15, 0)
+#define XDMAC_TSS 0x30
+#define XDMAC_TSS_REQ BIT(0)
+#define XDMAC_IEN 0x34
+#define XDMAC_IEN_ERRIEN BIT(1)
+#define XDMAC_IEN_ENDIEN BIT(0)
+#define XDMAC_STAT 0x40
+#define XDMAC_STAT_TENF BIT(0)
+#define XDMAC_IR 0x44
+#define XDMAC_IR_ERRF BIT(1)
+#define XDMAC_IR_ENDF BIT(0)
+#define XDMAC_ID 0x48
+#define XDMAC_ID_ERRIDF BIT(1)
+#define XDMAC_ID_ENDIDF BIT(0)
+
+#define XDMAC_MAX_CHANS 16
+#define XDMAC_INTERVAL_CLKS 20
+#define XDMAC_MAX_WORDS XDMAC_TNUM_MASK
+
+/* cut lower bit for maintain alignment of maximum transfer size */
+#define XDMAC_MAX_WORD_SIZE (XDMAC_ITS_MASK & ~GENMASK(3, 0))
+
+#define UNIPHIER_XDMAC_BUSWIDTHS \
+ (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
+ BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
+ BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
+ BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
+
+struct uniphier_xdmac_desc_node {
+ dma_addr_t src;
+ dma_addr_t dst;
+ u32 burst_size;
+ u32 nr_burst;
+};
+
+struct uniphier_xdmac_desc {
+ struct virt_dma_desc vd;
+
+ unsigned int nr_node;
+ unsigned int cur_node;
+ enum dma_transfer_direction dir;
+ struct uniphier_xdmac_desc_node nodes[0];
+};
+
+struct uniphier_xdmac_chan {
+ struct virt_dma_chan vc;
+ struct uniphier_xdmac_device *xdev;
+ struct uniphier_xdmac_desc *xd;
+ void __iomem *reg_ch_base;
+ struct dma_slave_config sconfig;
+ int id;
+ unsigned int req_factor;
+};
+
+struct uniphier_xdmac_device {
+ struct dma_device ddev;
+ void __iomem *reg_base;
+ int nr_chans;
+ struct uniphier_xdmac_chan channels[0];
+};
+
+static struct uniphier_xdmac_chan *
+to_uniphier_xdmac_chan(struct virt_dma_chan *vc)
+{
+ return container_of(vc, struct uniphier_xdmac_chan, vc);
+}
+
+static struct uniphier_xdmac_desc *
+to_uniphier_xdmac_desc(struct virt_dma_desc *vd)
+{
+ return container_of(vd, struct uniphier_xdmac_desc, vd);
+}
+
+/* xc->vc.lock must be held by caller */
+static struct uniphier_xdmac_desc *
+uniphier_xdmac_next_desc(struct uniphier_xdmac_chan *xc)
+{
+ struct virt_dma_desc *vd;
+
+ vd = vchan_next_desc(&xc->vc);
+ if (!vd)
+ return NULL;
+
+ list_del(&vd->node);
+
+ return to_uniphier_xdmac_desc(vd);
+}
+
+/* xc->vc.lock must be held by caller */
+static void uniphier_xdmac_chan_start(struct uniphier_xdmac_chan *xc,
+ struct uniphier_xdmac_desc *xd)
+{
+ u32 src_mode, src_addr, src_width;
+ u32 dst_mode, dst_addr, dst_width;
+ u32 val, its, tnum;
+ enum dma_slave_buswidth buswidth;
+
+ src_addr = xd->nodes[xd->cur_node].src;
+ dst_addr = xd->nodes[xd->cur_node].dst;
+ its = xd->nodes[xd->cur_node].burst_size;
+ tnum = xd->nodes[xd->cur_node].nr_burst;
+
+ /*
+ * The width of MEM side must be 4 or 8 bytes, that does not
+ * affect that of DEV side and transfer size.
+ */
+ if (xd->dir == DMA_DEV_TO_MEM) {
+ src_mode = XDMAC_SADM_SAM_FIXED;
+ buswidth = xc->sconfig.src_addr_width;
+ } else {
+ src_mode = XDMAC_SADM_SAM_INC;
+ buswidth = DMA_SLAVE_BUSWIDTH_8_BYTES;
+ }
+ src_width = FIELD_PREP(XDMAC_SADM_STW_MASK, __ffs(buswidth));
+
+ if (xd->dir == DMA_MEM_TO_DEV) {
+ dst_mode = XDMAC_DADM_DAM_FIXED;
+ buswidth = xc->sconfig.dst_addr_width;
+ } else {
+ dst_mode = XDMAC_DADM_DAM_INC;
+ buswidth = DMA_SLAVE_BUSWIDTH_8_BYTES;
+ }
+ dst_width = FIELD_PREP(XDMAC_DADM_DTW_MASK, __ffs(buswidth));
+
+ /* setup transfer factor */
+ val = FIELD_PREP(XDMAC_TFA_MCNT_MASK, XDMAC_INTERVAL_CLKS);
+ val |= FIELD_PREP(XDMAC_TFA_MASK, xc->req_factor);
+ writel(val, xc->reg_ch_base + XDMAC_TFA);
+
+ /* setup the channel */
+ writel(lower_32_bits(src_addr), xc->reg_ch_base + XDMAC_SAD);
+ writel(upper_32_bits(src_addr), xc->reg_ch_base + XDMAC_EXSAD);
+
+ writel(lower_32_bits(dst_addr), xc->reg_ch_base + XDMAC_DAD);
+ writel(upper_32_bits(dst_addr), xc->reg_ch_base + XDMAC_EXDAD);
+
+ src_mode |= src_width;
+ dst_mode |= dst_width;
+ writel(src_mode, xc->reg_ch_base + XDMAC_SADM);
+ writel(dst_mode, xc->reg_ch_base + XDMAC_DADM);
+
+ writel(its, xc->reg_ch_base + XDMAC_ITS);
+ writel(tnum, xc->reg_ch_base + XDMAC_TNUM);
+
+ /* enable interrupt */
+ writel(XDMAC_IEN_ENDIEN | XDMAC_IEN_ERRIEN,
+ xc->reg_ch_base + XDMAC_IEN);
+
+ /* start XDMAC */
+ val = readl(xc->reg_ch_base + XDMAC_TSS);
+ val |= XDMAC_TSS_REQ;
+ writel(val, xc->reg_ch_base + XDMAC_TSS);
+}
+
+/* xc->vc.lock must be held by caller */
+static int uniphier_xdmac_chan_stop(struct uniphier_xdmac_chan *xc)
+{
+ u32 val;
+
+ /* disable interrupt */
+ val = readl(xc->reg_ch_base + XDMAC_IEN);
+ val &= ~(XDMAC_IEN_ENDIEN | XDMAC_IEN_ERRIEN);
+ writel(val, xc->reg_ch_base + XDMAC_IEN);
+
+ /* stop XDMAC */
+ val = readl(xc->reg_ch_base + XDMAC_TSS);
+ val &= ~XDMAC_TSS_REQ;
+ writel(0, xc->reg_ch_base + XDMAC_TSS);
+
+ /* wait until transfer is stopped */
+ return readl_poll_timeout(xc->reg_ch_base + XDMAC_STAT, val,
+ !(val & XDMAC_STAT_TENF), 100, 1000);
+}
+
+/* xc->vc.lock must be held by caller */
+static void uniphier_xdmac_start(struct uniphier_xdmac_chan *xc)
+{
+ struct uniphier_xdmac_desc *xd;
+
+ xd = uniphier_xdmac_next_desc(xc);
+ if (xd)
+ uniphier_xdmac_chan_start(xc, xd);
+
+ /* set desc to chan regardless of xd is null */
+ xc->xd = xd;
+}
+
+static void uniphier_xdmac_chan_irq(struct uniphier_xdmac_chan *xc)
+{
+ u32 stat;
+ int ret;
+
+ spin_lock(&xc->vc.lock);
+
+ stat = readl(xc->reg_ch_base + XDMAC_ID);
+
+ if (stat & XDMAC_ID_ERRIDF) {
+ ret = uniphier_xdmac_chan_stop(xc);
+ if (ret)
+ dev_err(xc->xdev->ddev.dev,
+ "DMA transfer error with aborting issue\n");
+ else
+ dev_err(xc->xdev->ddev.dev,
+ "DMA transfer error\n");
+
+ } else if ((stat & XDMAC_ID_ENDIDF) && xc->xd) {
+ xc->xd->cur_node++;
+ if (xc->xd->cur_node >= xc->xd->nr_node) {
+ vchan_cookie_complete(&xc->xd->vd);
+ uniphier_xdmac_start(xc);
+ } else {
+ uniphier_xdmac_chan_start(xc, xc->xd);
+ }
+ }
+
+ /* write bits to clear */
+ writel(stat, xc->reg_ch_base + XDMAC_IR);
+
+ spin_unlock(&xc->vc.lock);
+}
+
+static irqreturn_t uniphier_xdmac_irq_handler(int irq, void *dev_id)
+{
+ struct uniphier_xdmac_device *xdev = dev_id;
+ int i;
+
+ for (i = 0; i < xdev->nr_chans; i++)
+ uniphier_xdmac_chan_irq(&xdev->channels[i]);
+
+ return IRQ_HANDLED;
+}
+
+static void uniphier_xdmac_free_chan_resources(struct dma_chan *chan)
+{
+ vchan_free_chan_resources(to_virt_chan(chan));
+}
+
+static struct dma_async_tx_descriptor *
+uniphier_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst,
+ dma_addr_t src, size_t len, unsigned long flags)
+{
+ struct virt_dma_chan *vc = to_virt_chan(chan);
+ struct uniphier_xdmac_desc *xd;
+ unsigned int nr = 1;
+ size_t burst_size, tlen;
+ int i;
+
+ if (len > XDMAC_MAX_WORD_SIZE * XDMAC_MAX_WORDS)
+ return NULL;
+
+ if ((len > XDMAC_MAX_WORD_SIZE) && (len % XDMAC_MAX_WORD_SIZE))
+ nr++;
+
+ xd = kzalloc(struct_size(xd, nodes, nr), GFP_NOWAIT);
+ if (!xd)
+ return NULL;
+
+ for (i = 0; i < nr; i++) {
+ burst_size = min_t(size_t, len, XDMAC_MAX_WORD_SIZE);
+ xd->nodes[i].src = src;
+ xd->nodes[i].dst = dst;
+ xd->nodes[i].burst_size = burst_size;
+ xd->nodes[i].nr_burst = len / burst_size;
+ tlen = rounddown(len, burst_size);
+ src += tlen;
+ dst += tlen;
+ len -= tlen;
+ }
+
+ xd->dir = DMA_MEM_TO_MEM;
+ xd->nr_node = nr;
+ xd->cur_node = 0;
+
+ return vchan_tx_prep(vc, &xd->vd, flags);
+}
+
+static struct dma_async_tx_descriptor *
+uniphier_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+ unsigned int sg_len,
+ enum dma_transfer_direction direction,
+ unsigned long flags, void *context)
+{
+ struct virt_dma_chan *vc = to_virt_chan(chan);
+ struct uniphier_xdmac_chan *xc = to_uniphier_xdmac_chan(vc);
+ struct uniphier_xdmac_desc *xd;
+ struct scatterlist *sg;
+ enum dma_slave_buswidth buswidth;
+ u32 maxburst;
+ int i;
+
+ if (!is_slave_direction(direction))
+ return NULL;
+
+ if (direction == DMA_DEV_TO_MEM) {
+ buswidth = xc->sconfig.src_addr_width;
+ maxburst = xc->sconfig.src_maxburst;
+ } else {
+ buswidth = xc->sconfig.dst_addr_width;
+ maxburst = xc->sconfig.dst_maxburst;
+ }
+
+ if (!maxburst)
+ maxburst = 1;
+ if (maxburst > xc->xdev->ddev.max_burst) {
+ dev_err(xc->xdev->ddev.dev,
+ "Exceed maximum number of burst words\n");
+ return NULL;
+ }
+
+ xd = kzalloc(struct_size(xd, nodes, sg_len), GFP_NOWAIT);
+ if (!xd)
+ return NULL;
+
+ for_each_sg(sgl, sg, sg_len, i) {
+ xd->nodes[i].src = (direction == DMA_DEV_TO_MEM)
+ ? xc->sconfig.src_addr : sg_dma_address(sg);
+ xd->nodes[i].dst = (direction == DMA_MEM_TO_DEV)
+ ? xc->sconfig.dst_addr : sg_dma_address(sg);
+ xd->nodes[i].burst_size = maxburst * buswidth;
+ xd->nodes[i].nr_burst =
+ sg_dma_len(sg) / xd->nodes[i].burst_size;
+
+ /*
+ * Currently transfer that size doesn't align the unit size
+ * (the number of burst words * bus-width) is not allowed,
+ * because the driver does not support the way to transfer
+ * residue size. As a matter of fact, in order to transfer
+ * arbitrary size, 'src_maxburst' or 'dst_maxburst' of
+ * dma_slave_config must be 1.
+ */
+ if (sg_dma_len(sg) % xd->nodes[i].burst_size) {
+ dev_err(xc->xdev->ddev.dev,
+ "Unaligned transfer size: %d", sg_dma_len(sg));
+ kfree(xd);
+ return NULL;
+ }
+
+ if (xd->nodes[i].nr_burst > XDMAC_MAX_WORDS) {
+ dev_err(xc->xdev->ddev.dev,
+ "Exceed maximum transfer size");
+ kfree(xd);
+ return NULL;
+ }
+ }
+
+ xd->dir = direction;
+ xd->nr_node = sg_len;
+ xd->cur_node = 0;
+
+ return vchan_tx_prep(vc, &xd->vd, flags);
+}
+
+static int uniphier_xdmac_slave_config(struct dma_chan *chan,
+ struct dma_slave_config *config)
+{
+ struct virt_dma_chan *vc = to_virt_chan(chan);
+ struct uniphier_xdmac_chan *xc = to_uniphier_xdmac_chan(vc);
+
+ memcpy(&xc->sconfig, config, sizeof(*config));
+
+ return 0;
+}
+
+static int uniphier_xdmac_terminate_all(struct dma_chan *chan)
+{
+ struct virt_dma_chan *vc = to_virt_chan(chan);
+ struct uniphier_xdmac_chan *xc = to_uniphier_xdmac_chan(vc);
+ unsigned long flags;
+ int ret = 0;
+ LIST_HEAD(head);
+
+ spin_lock_irqsave(&vc->lock, flags);
+
+ if (xc->xd) {
+ vchan_terminate_vdesc(&xc->xd->vd);
+ xc->xd = NULL;
+ ret = uniphier_xdmac_chan_stop(xc);
+ }
+
+ vchan_get_all_descriptors(vc, &head);
+
+ spin_unlock_irqrestore(&vc->lock, flags);
+
+ vchan_dma_desc_free_list(vc, &head);
+
+ return ret;
+}
+
+static void uniphier_xdmac_synchronize(struct dma_chan *chan)
+{
+ vchan_synchronize(to_virt_chan(chan));
+}
+
+static void uniphier_xdmac_issue_pending(struct dma_chan *chan)
+{
+ struct virt_dma_chan *vc = to_virt_chan(chan);
+ struct uniphier_xdmac_chan *xc = to_uniphier_xdmac_chan(vc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&vc->lock, flags);
+
+ if (vchan_issue_pending(vc) && !xc->xd)
+ uniphier_xdmac_start(xc);
+
+ spin_unlock_irqrestore(&vc->lock, flags);
+}
+
+static void uniphier_xdmac_desc_free(struct virt_dma_desc *vd)
+{
+ kfree(to_uniphier_xdmac_desc(vd));
+}
+
+static int uniphier_xdmac_chan_init(struct uniphier_xdmac_device *xdev,
+ int ch)
+{
+ struct uniphier_xdmac_chan *xc = &xdev->channels[ch];
+
+ xc->xdev = xdev;
+ xc->reg_ch_base = xdev->reg_base + XDMAC_CH_WIDTH * ch;
+ xc->vc.desc_free = uniphier_xdmac_desc_free;
+
+ vchan_init(&xc->vc, &xdev->ddev);
+
+ return 0;
+}
+
+static struct dma_chan *of_dma_uniphier_xlate(struct of_phandle_args *dma_spec,
+ struct of_dma *ofdma)
+{
+ struct uniphier_xdmac_device *xdev = ofdma->of_dma_data;
+ int chan_id = dma_spec->args[0];
+
+ if (chan_id >= xdev->nr_chans)
+ return NULL;
+
+ xdev->channels[chan_id].id = chan_id;
+ xdev->channels[chan_id].req_factor = dma_spec->args[1];
+
+ return dma_get_slave_channel(&xdev->channels[chan_id].vc.chan);
+}
+
+static int uniphier_xdmac_probe(struct platform_device *pdev)
+{
+ struct uniphier_xdmac_device *xdev;
+ struct device *dev = &pdev->dev;
+ struct dma_device *ddev;
+ int irq;
+ int nr_chans;
+ int i, ret;
+
+ if (of_property_read_u32(dev->of_node, "dma-channels", &nr_chans))
+ return -EINVAL;
+ if (nr_chans > XDMAC_MAX_CHANS)
+ nr_chans = XDMAC_MAX_CHANS;
+
+ xdev = devm_kzalloc(dev, struct_size(xdev, channels, nr_chans),
+ GFP_KERNEL);
+ if (!xdev)
+ return -ENOMEM;
+
+ xdev->nr_chans = nr_chans;
+ xdev->reg_base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(xdev->reg_base))
+ return PTR_ERR(xdev->reg_base);
+
+ ddev = &xdev->ddev;
+ ddev->dev = dev;
+ dma_cap_zero(ddev->cap_mask);
+ dma_cap_set(DMA_MEMCPY, ddev->cap_mask);
+ dma_cap_set(DMA_SLAVE, ddev->cap_mask);
+ ddev->src_addr_widths = UNIPHIER_XDMAC_BUSWIDTHS;
+ ddev->dst_addr_widths = UNIPHIER_XDMAC_BUSWIDTHS;
+ ddev->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
+ BIT(DMA_MEM_TO_MEM);
+ ddev->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+ ddev->max_burst = XDMAC_MAX_WORDS;
+ ddev->device_free_chan_resources = uniphier_xdmac_free_chan_resources;
+ ddev->device_prep_dma_memcpy = uniphier_xdmac_prep_dma_memcpy;
+ ddev->device_prep_slave_sg = uniphier_xdmac_prep_slave_sg;
+ ddev->device_config = uniphier_xdmac_slave_config;
+ ddev->device_terminate_all = uniphier_xdmac_terminate_all;
+ ddev->device_synchronize = uniphier_xdmac_synchronize;
+ ddev->device_tx_status = dma_cookie_status;
+ ddev->device_issue_pending = uniphier_xdmac_issue_pending;
+ INIT_LIST_HEAD(&ddev->channels);
+
+ for (i = 0; i < nr_chans; i++) {
+ ret = uniphier_xdmac_chan_init(xdev, i);
+ if (ret) {
+ dev_err(dev,
+ "Failed to initialize XDMAC channel %d\n", i);
+ return ret;
+ }
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(dev, "Failed to get IRQ\n");
+ return irq;
+ }
+
+ ret = devm_request_irq(dev, irq, uniphier_xdmac_irq_handler,
+ IRQF_SHARED, "xdmac", xdev);
+ if (ret) {
+ dev_err(dev, "Failed to request IRQ\n");
+ return ret;
+ }
+
+ ret = dma_async_device_register(ddev);
+ if (ret) {
+ dev_err(dev, "Failed to register XDMA device\n");
+ return ret;
+ }
+
+ ret = of_dma_controller_register(dev->of_node,
+ of_dma_uniphier_xlate, xdev);
+ if (ret) {
+ dev_err(dev, "Failed to register XDMA controller\n");
+ goto out_unregister_dmac;
+ }
+
+ platform_set_drvdata(pdev, xdev);
+
+ dev_info(&pdev->dev, "UniPhier XDMAC driver (%d channels)\n",
+ nr_chans);
+
+ return 0;
+
+out_unregister_dmac:
+ dma_async_device_unregister(ddev);
+
+ return ret;
+}
+
+static int uniphier_xdmac_remove(struct platform_device *pdev)
+{
+ struct uniphier_xdmac_device *xdev = platform_get_drvdata(pdev);
+ struct dma_device *ddev = &xdev->ddev;
+ struct dma_chan *chan;
+ int ret;
+
+ /*
+ * Before reaching here, almost all descriptors have been freed by the
+ * ->device_free_chan_resources() hook. However, each channel might
+ * be still holding one descriptor that was on-flight at that moment.
+ * Terminate it to make sure this hardware is no longer running. Then,
+ * free the channel resources once again to avoid memory leak.
+ */
+ list_for_each_entry(chan, &ddev->channels, device_node) {
+ ret = dmaengine_terminate_sync(chan);
+ if (ret)
+ return ret;
+ uniphier_xdmac_free_chan_resources(chan);
+ }
+
+ of_dma_controller_free(pdev->dev.of_node);
+ dma_async_device_unregister(ddev);
+
+ return 0;
+}
+
+static const struct of_device_id uniphier_xdmac_match[] = {
+ { .compatible = "socionext,uniphier-xdmac" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_xdmac_match);
+
+static struct platform_driver uniphier_xdmac_driver = {
+ .probe = uniphier_xdmac_probe,
+ .remove = uniphier_xdmac_remove,
+ .driver = {
+ .name = "uniphier-xdmac",
+ .of_match_table = uniphier_xdmac_match,
+ },
+};
+module_platform_driver(uniphier_xdmac_driver);
+
+MODULE_AUTHOR("Kunihiko Hayashi <hayashi.kunihiko@socionext.com>");
+MODULE_DESCRIPTION("UniPhier external DMA controller driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4
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