The Loongson LS2X APB DMA controller is available on Loongson-2K chips.
It is a single-channel, configurable DMA controller IP core based on the
AXI bus, whose main function is to integrate DMA functionality on a chip
dedicated to carrying data between memory and peripherals in APB bus
(e.g. nand).
Signed-off-by: Binbin Zhou <zhoubinbin@xxxxxxxxxxx>
Signed-off-by: Yingkun Meng <mengyingkun@xxxxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/dma/Kconfig | 14 +
drivers/dma/Makefile | 1 +
drivers/dma/ls2x-apb-dma.c | 684 +++++++++++++++++++++++++++++++++++++
4 files changed, 700 insertions(+)
create mode 100644 drivers/dma/ls2x-apb-dma.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 60a411936ba7..709c2e9d5f5f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12248,6 +12248,7 @@ M: Binbin Zhou <zhoubinbin@xxxxxxxxxxx>
L: dmaengine@xxxxxxxxxxxxxxx
S: Maintained
F: Documentation/devicetree/bindings/dma/loongson,ls2x-apbdma.yaml
+F: drivers/dma/ls2x-apb-dma.c
LOONGSON LS2X I2C DRIVER
M: Binbin Zhou <zhoubinbin@xxxxxxxxxxx>
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 644c188d6a11..9b41b59ba2b4 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -376,6 +376,20 @@ config LPC18XX_DMAMUX
Enable support for DMA on NXP LPC18xx/43xx platforms
with PL080 and multiplexed DMA request lines.
+config LS2X_APB_DMA
+ tristate "Loongson LS2X APB DMA support"
+ depends on LOONGARCH || COMPILE_TEST
+ select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
+ help
+ Support for the Loongson LS2X APB DMA controller driver. The
+ DMA controller is having single DMA channel which can be
+ configured for different peripherals like audio, nand, sdio
+ etc which is in APB bus.
+
+ This DMA controller transfers data from memory to peripheral fifo.
+ It does not support memory to memory data transfer.
+
config MCF_EDMA
tristate "Freescale eDMA engine support, ColdFire mcf5441x SoCs"
depends on M5441x || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index a4fd1ce29510..9b28ddb1ea3b 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_INTEL_IOATDMA) += ioat/
obj-y += idxd/
obj-$(CONFIG_K3_DMA) += k3dma.o
obj-$(CONFIG_LPC18XX_DMAMUX) += lpc18xx-dmamux.o
+obj-$(CONFIG_LS2X_APB_DMA) += ls2x-apb-dma.o
obj-$(CONFIG_MILBEAUT_HDMAC) += milbeaut-hdmac.o
obj-$(CONFIG_MILBEAUT_XDMAC) += milbeaut-xdmac.o
obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o
diff --git a/drivers/dma/ls2x-apb-dma.c b/drivers/dma/ls2x-apb-dma.c
new file mode 100644
index 000000000000..b3efe86e4330
--- /dev/null
+++ b/drivers/dma/ls2x-apb-dma.c
@@ -0,0 +1,684 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for the Loongson LS2X APB DMA Controller
+ *
+ * Copyright (C) 2017-2023 Loongson Corporation
+ */
+
+#include <linux/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+
+#include "dmaengine.h"
+#include "virt-dma.h"
+
+/* Global Configuration Register */
+#define LDMA_ORDER_ERG 0x0
+
+/* Bitfield definitions */
+
+/* Bitfields in Global Configuration Register */
+#define LDMA_64BIT_EN BIT(0) /* 1: 64 bit support */
+#define LDMA_UNCOHERENT_EN BIT(1) /* 0: cache, 1: uncache */
+#define LDMA_ASK_VALID BIT(2)
+#define LDMA_START BIT(3) /* DMA start operation */
+#define LDMA_STOP BIT(4) /* DMA stop operation */
+#define LDMA_CONFIG_MASK GENMASK(4, 0) /* DMA controller config bits mask */
+
+/* Bitfields in ndesc_addr field of HW decriptor */
+#define LDMA_DESC_EN BIT(0) /*1: The next descriptor is valid */
+#define LDMA_DESC_ADDR_LOW GENMASK(31, 1)
+
+/* Bitfields in cmd field of HW decriptor */
+#define LDMA_INT BIT(1) /* Enable DMA interrupts */
+#define LDMA_DATA_DIRECTION BIT(12) /* 1: write to device, 0: read from device */
+
+/*-- descriptors -----------------------------------------------------*/
+
+/*
+ * struct ls2x_dma_hw_desc - DMA HW descriptor
+ * @ndesc_addr: the next descriptor low address.
+ * @mem_addr: memory low address.
+ * @apb_addr: device buffer address.
+ * @len: length of a piece of carried content, in words.
+ * @step_len: length between two moved memory data blocks.
+ * @step_times: number of blocks to be carried in a single DMA operation.
+ * @cmd: descriptor command or state.
+ * @stats: DMA status.
+ * @high_ndesc_addr: the next descriptor high address.
+ * @high_mem_addr: memory high address.
+ * @reserved: reserved
+ */
+struct ls2x_dma_hw_desc {
+ u32 ndesc_addr;
+ u32 mem_addr;
+ u32 apb_addr;
+ u32 len;
+ u32 step_len;
+ u32 step_times;
+ u32 cmd;
+ u32 stats;
+ u32 high_ndesc_addr;
+ u32 high_mem_addr;
+ u32 reserved[2];
+} __packed;
+
+/*
+ * struct ls2x_dma_sg - ls2x dma scatter gather entry
+ * @hw: the pointer to DMA HW descriptor.
+ * @llp: physical address of the DMA HW descriptor.
+ * @phys: destination or source address(mem).
+ * @len: number of Bytes to read.
+ */
+struct ls2x_dma_sg {
+ struct ls2x_dma_hw_desc *hw;
+ dma_addr_t llp;
+ dma_addr_t phys;
+ u32 len;
+};
+
+/*
+ * struct ls2x_dma_desc - software descriptor
+ * @vdesc: pointer to the virtual dma descriptor.
+ * @cyclic: flag to dma cyclic
+ * @sglen: number of sg entries.
+ * @direction: transfer direction, to or from device.
+ * @status: dma controller status.
+ * @sg: array of sgs.
+ */
+struct ls2x_dma_desc {
+ struct virt_dma_desc vdesc;
+ bool cyclic;
+ u32 sglen;
+ enum dma_transfer_direction direction;
+ enum dma_status status;
+ struct ls2x_dma_sg sg[];
+};
+
+/*-- Channels --------------------------------------------------------*/
+
+/*
+ * struct ls2x_dma_chan - internal representation of an LS2X APB DMA channel
+ * @vchan: virtual dma channel entry.
+ * @desc: pointer to the ls2x sw dma descriptor.
+ * @pool: hw desc table
+ * @irq: irq line
+ * @sconfig: configuration for slave transfers, passed via .device_config
+ */
+struct ls2x_dma_chan {
+ struct virt_dma_chan vchan;
+ struct ls2x_dma_desc *desc;
+ void *pool;
+ int irq;
+ struct dma_slave_config sconfig;
+};
+
+/*-- Controller ------------------------------------------------------*/
+
+/*
+ * struct ls2x_dma_priv - LS2X APB DMAC specific information
+ * @ddev: dmaengine dma_device object members
+ * @dma_clk: DMAC clock source
+ * @regs: memory mapped register base
+ * @lchan: channel to store ls2x_dma_chan structures
+ */
+struct ls2x_dma_priv {
+ struct dma_device ddev;
+ struct clk *dma_clk;
+ void __iomem *regs;
+ struct ls2x_dma_chan lchan;
+};
+
+/*-- Helper functions ------------------------------------------------*/
+
+static inline struct ls2x_dma_desc *to_ldma_desc(struct virt_dma_desc *vdesc)
+{
+ return container_of(vdesc, struct ls2x_dma_desc, vdesc);
+}
+
+static inline struct ls2x_dma_chan *to_ldma_chan(struct dma_chan *chan)
+{
+ return container_of(chan, struct ls2x_dma_chan, vchan.chan);
+}
+
+static inline struct ls2x_dma_priv *to_ldma_priv(struct dma_device *ddev)
+{
+ return container_of(ddev, struct ls2x_dma_priv, ddev);
+}
+
+static struct device *chan2dev(struct dma_chan *chan)
+{
+ return &chan->dev->device;
+}
+
+static void ls2x_dma_desc_free(struct virt_dma_desc *vdesc)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(vdesc->tx.chan);
+ struct ls2x_dma_desc *desc = to_ldma_desc(vdesc);
+ int i;
+
+ for (i = 0; i < desc->sglen; i++) {
+ if (desc->sg[i].hw)
+ dma_pool_free(lchan->pool, desc->sg[i].hw,
+ desc->sg[i].llp);
+ }
+
+ kfree(desc);
+}
+
+static void ls2x_dma_write_cmd(struct ls2x_dma_chan *lchan, bool cmd)
+{
+ u64 val = 0;
+ struct ls2x_dma_priv *priv = to_ldma_priv(lchan->vchan.chan.device);
+
+ val = lo_hi_readq(priv->regs + LDMA_ORDER_ERG) & ~LDMA_CONFIG_MASK;
+ val |= LDMA_64BIT_EN | cmd;
+ lo_hi_writeq(val, priv->regs + LDMA_ORDER_ERG);
+}
+
+static void ls2x_dma_start_transfer(struct ls2x_dma_chan *lchan)
+{
+ struct ls2x_dma_priv *priv = to_ldma_priv(lchan->vchan.chan.device);
+ struct ls2x_dma_sg *ldma_sg;
+ struct virt_dma_desc *vdesc;
+ u64 val;
+
+ /* Get the next descriptor */
+ vdesc = vchan_next_desc(&lchan->vchan);
+ if (!vdesc) {
+ lchan->desc = NULL;
+ return;
+ }
+
+ list_del(&vdesc->node);
+ lchan->desc = to_ldma_desc(vdesc);
+ ldma_sg = &lchan->desc->sg[0];
+
+ /* Start DMA */
+ lo_hi_writeq(0, priv->regs + LDMA_ORDER_ERG);
+ val = (ldma_sg->llp & ~LDMA_CONFIG_MASK) | LDMA_64BIT_EN | LDMA_START;
+ lo_hi_writeq(val, priv->regs + LDMA_ORDER_ERG);
+}
+
+static void ls2x_dma_fill_desc(struct ls2x_dma_chan *lchan, u32 i,
+ struct ls2x_dma_desc *desc)
+{
+ struct ls2x_dma_sg *ldma_sg = &desc->sg[i];
+
+ ldma_sg->hw->mem_addr = lower_32_bits(ldma_sg->phys);
+ ldma_sg->hw->high_mem_addr = upper_32_bits(ldma_sg->phys);
+ /* Word count register takes input in words */
+ ldma_sg->hw->len = ldma_sg->len >> 2;
+ ldma_sg->hw->step_len = 0;
+ ldma_sg->hw->step_times = 1;
+
+ if (desc->direction == DMA_MEM_TO_DEV) {
+ ldma_sg->hw->cmd = LDMA_INT | LDMA_DATA_DIRECTION;
+ ldma_sg->hw->apb_addr = lchan->sconfig.dst_addr;
+ } else {
+ ldma_sg->hw->cmd = LDMA_INT;
+ ldma_sg->hw->apb_addr = lchan->sconfig.src_addr;
+ }
+
+ /* lets make a link list */
+ if (i) {
+ desc->sg[i - 1].hw->ndesc_addr = ldma_sg->llp | LDMA_DESC_EN;
+ desc->sg[i - 1].hw->high_ndesc_addr = upper_32_bits(ldma_sg->llp);
+ }
+}
+
+/*-- DMA Engine API --------------------------------------------------*/
+
+/*
+ * ls2x_dma_alloc_chan_resources - allocate resources for DMA channel
+ * @chan: allocate descriptor resources for this channel
+ *
+ * return - the number of allocated descriptors
+ */
+static int ls2x_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+
+ /* Create a pool of consistent memory blocks for hardware descriptors */
+ lchan->pool = dma_pool_create(dev_name(chan2dev(chan)),
+ chan->device->dev, PAGE_SIZE,
+ __alignof__(struct ls2x_dma_hw_desc), 0);
+ if (!lchan->pool) {
+ dev_err(chan2dev(chan), "No memory for descriptors\n");
+ return -ENOMEM;
+ }
+
+ return 1;
+}
+
+/*
+ * ls2x_dma_free_chan_resources - free all channel resources
+ * @chan: DMA channel
+ */
+static void ls2x_dma_free_chan_resources(struct dma_chan *chan)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+
+ vchan_free_chan_resources(to_virt_chan(chan));
+ dma_pool_destroy(lchan->pool);
+ lchan->pool = NULL;
+}
+
+/*
+ * ls2x_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
+ * @chan: DMA channel
+ * @sgl: scatterlist to transfer to/from
+ * @sg_len: number of entries in @scatterlist
+ * @direction: DMA direction
+ * @flags: tx descriptor status flags
+ * @context: transaction context (ignored)
+ *
+ * Return: Async transaction descriptor on success and NULL on failure
+ */
+static struct dma_async_tx_descriptor *
+ls2x_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+ u32 sg_len, enum dma_transfer_direction direction,
+ unsigned long flags, void *context)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+ struct ls2x_dma_desc *desc;
+ struct scatterlist *sg;
+ int i;
+
+ if (unlikely(!sg_len || !is_slave_direction(direction)))
+ return NULL;
+
+ desc = kzalloc(struct_size(desc, sg, sg_len), GFP_ATOMIC);
+ if (!desc)
+ return NULL;
+ desc->sglen = sg_len;
+ desc->direction = direction;
+
+ for_each_sg(sgl, sg, sg_len, i) {
+ struct ls2x_dma_sg *ldma_sg = &desc->sg[i];
+
+ /* Allocate DMA capable memory for hardware descriptor */
+ ldma_sg->hw = dma_pool_alloc(lchan->pool, GFP_NOWAIT, &ldma_sg->llp);
+ if (!ldma_sg->hw) {
+ desc->sglen = i;
+ ls2x_dma_desc_free(&desc->vdesc);
+ return NULL;
+ }
+
+ ldma_sg->phys = sg_dma_address(sg);
+ ldma_sg->len = sg_dma_len(sg);
+
+ ls2x_dma_fill_desc(lchan, i, desc);
+ }
+
+ /* Setting the last descriptor enable bit */
+ desc->sg[sg_len - 1].hw->ndesc_addr &= ~LDMA_DESC_EN;
+ desc->status = DMA_IN_PROGRESS;
+
+ return vchan_tx_prep(&lchan->vchan, &desc->vdesc, flags);
+}
+
+/*
+ * ls2x_dma_prep_dma_cyclic - prepare the cyclic DMA transfer
+ * @chan: the DMA channel to prepare
+ * @buf_addr: physical DMA address where the buffer starts
+ * @buf_len: total number of bytes for the entire buffer
+ * @period_len: number of bytes for each period
+ * @direction: transfer direction, to or from device
+ * @flags: tx descriptor status flags
+ *
+ * Return: Async transaction descriptor on success and NULL on failure
+ */
+static struct dma_async_tx_descriptor *
+ls2x_dma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
+ size_t period_len, enum dma_transfer_direction direction,
+ unsigned long flags)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+ struct ls2x_dma_desc *desc;
+ u32 periods;
+ int i;
+
+ if (unlikely(!buf_len || !period_len))
+ return NULL;
+
+ if (unlikely(!is_slave_direction(direction)))
+ return NULL;
+
+ periods = buf_len / period_len;
+ desc = kzalloc(struct_size(desc, sg, periods), GFP_ATOMIC);
+ if (!desc)
+ return NULL;
+ desc->sglen = periods;
+ desc->direction = direction;
+
+ /* Build cyclic linked list */
+ for (i = 0; i < periods; i++) {
+ struct ls2x_dma_sg *ldma_sg = &desc->sg[i];
+
+ /* Allocate DMA capable memory for hardware descriptor */
+ ldma_sg->hw = dma_pool_alloc(lchan->pool, GFP_NOWAIT, &ldma_sg->llp);
+ if (!ldma_sg->hw) {
+ desc->sglen = i;
+ ls2x_dma_desc_free(&desc->vdesc);
+ return NULL;
+ }
+
+ ldma_sg->phys = buf_addr + period_len * i;
+ ldma_sg->len = period_len;
+
+ ls2x_dma_fill_desc(lchan, i, desc);
+ }
+
+ /* Lets make a cyclic list */
+ desc->sg[periods - 1].hw->ndesc_addr = desc->sg[0].llp | LDMA_DESC_EN;
+ desc->sg[periods - 1].hw->high_ndesc_addr = upper_32_bits(desc->sg[0].llp);
+ desc->cyclic = true;
+ desc->status = DMA_IN_PROGRESS;
+
+ return vchan_tx_prep(&lchan->vchan, &desc->vdesc, flags);
+}
+
+/*
+ * ls2x_slave_config - set slave configuration for channel
+ * @chan: dma channel
+ * @cfg: slave configuration
+ *
+ * Sets slave configuration for channel
+ */
+static int ls2x_dma_slave_config(struct dma_chan *chan,
+ struct dma_slave_config *config)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+
+ memcpy(&lchan->sconfig, config, sizeof(*config));
+ return 0;
+}
+
+/*
+ * ls2x_dma_issue_pending - push pending transactions to the hardware
+ * @chan: channel
+ *
+ * When this function is called, all pending transactions are pushed to the
+ * hardware and executed.
+ */
+static void ls2x_dma_issue_pending(struct dma_chan *chan)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+ unsigned long flags;
+
+ spin_lock_irqsave(&lchan->vchan.lock, flags);
+ if (vchan_issue_pending(&lchan->vchan) && !lchan->desc)
+ ls2x_dma_start_transfer(lchan);
+ spin_unlock_irqrestore(&lchan->vchan.lock, flags);
+}
+
+/*
+ * ls2x_dma_terminate_all - terminate all transactions
+ * @chan: channel
+ *
+ * Stops all DMA transactions.
+ */
+static int ls2x_dma_terminate_all(struct dma_chan *chan)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+ unsigned long flags;
+ LIST_HEAD(head);
+
+ spin_lock_irqsave(&lchan->vchan.lock, flags);
+ /* Setting stop cmd */
+ ls2x_dma_write_cmd(lchan, LDMA_STOP);
+ if (lchan->desc) {
+ vchan_terminate_vdesc(&lchan->desc->vdesc);
+ lchan->desc = NULL;
+ }
+
+ vchan_get_all_descriptors(&lchan->vchan, &head);
+ spin_unlock_irqrestore(&lchan->vchan.lock, flags);
+
+ vchan_dma_desc_free_list(&lchan->vchan, &head);
+ return 0;
+}
+
+/*
+ * ls2x_dma_synchronize - Synchronizes the termination of transfers to the
+ * current context.
+ * @chan: channel
+ */
+static void ls2x_dma_synchronize(struct dma_chan *chan)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+
+ vchan_synchronize(&lchan->vchan);
+}
+
+static int ls2x_dma_pause(struct dma_chan *chan)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+ unsigned long flags;
+
+ spin_lock_irqsave(&lchan->vchan.lock, flags);
+ if (lchan->desc && lchan->desc->status == DMA_IN_PROGRESS) {
+ ls2x_dma_write_cmd(lchan, LDMA_STOP);
+ lchan->desc->status = DMA_PAUSED;
+ }
+ spin_unlock_irqrestore(&lchan->vchan.lock, flags);
+
+ return 0;
+}
+
+static int ls2x_dma_resume(struct dma_chan *chan)
+{
+ struct ls2x_dma_chan *lchan = to_ldma_chan(chan);
+ unsigned long flags;
+
+ spin_lock_irqsave(&lchan->vchan.lock, flags);
+ if (lchan->desc && lchan->desc->status == DMA_PAUSED) {
+ lchan->desc->status = DMA_IN_PROGRESS;
+ ls2x_dma_write_cmd(lchan, LDMA_START);
+ }
+ spin_unlock_irqrestore(&lchan->vchan.lock, flags);
+
+ return 0;
+}
+
+/*
+ * of_ls2x_dma_xlate - Translation function
+ * @dma_spec: Pointer to DMA specifier as found in the device tree
+ * @ofdma: Pointer to DMA controller data
+ *
+ * Return: DMA channel pointer on success and NULL on error
+ */
+static struct dma_chan *of_ls2x_dma_xlate(struct of_phandle_args *dma_spec,
+ struct of_dma *ofdma)
+{
+ struct ls2x_dma_priv *priv = ofdma->of_dma_data;
+ struct ls2x_dma_chan *lchan;
+
+ /* We are single channel DMA, just get the channel from priv. */
+ lchan = &priv->lchan;
+ if (!lchan)
+ return NULL;
+
+ return dma_get_slave_channel(&lchan->vchan.chan);
+}
+
+/*
+ * ls2x_dma_isr - LS2X DMA Interrupt handler
+ * @irq: IRQ number
+ * @dev_id: Pointer to ls2x_dma_chan
+ *
+ * Return: IRQ_HANDLED/IRQ_NONE
+ */
+static irqreturn_t ls2x_dma_isr(int irq, void *dev_id)
+{
+ struct ls2x_dma_chan *lchan = dev_id;
+ struct ls2x_dma_desc *desc;
+
+ spin_lock(&lchan->vchan.lock);
+ desc = lchan->desc;
+ if (desc) {
+ if (desc->cyclic) {
+ vchan_cyclic_callback(&desc->vdesc);
+ } else {
+ desc->status = DMA_COMPLETE;
+ vchan_cookie_complete(&desc->vdesc);
+ ls2x_dma_start_transfer(lchan);
+ }
+
+ /* ls2x_dma_start_transfer() updates lchan->desc */
+ if (!lchan->desc)
+ ls2x_dma_write_cmd(lchan, LDMA_STOP);
+ }
+ spin_unlock(&lchan->vchan.lock);
+
+ return IRQ_HANDLED;
+}
+
+static int ls2x_dma_chan_init(struct platform_device *pdev,
+ struct ls2x_dma_priv *priv)
+{
+ struct device *dev = &pdev->dev;
+ struct ls2x_dma_chan *lchan = &priv->lchan;
+ int ret;
+
+ lchan->irq = platform_get_irq(pdev, 0);
+ if (lchan->irq < 0)
+ return lchan->irq;
+
+ ret = devm_request_irq(dev, lchan->irq, ls2x_dma_isr, IRQF_TRIGGER_RISING,
+ dev_name(&pdev->dev), lchan);
+ if (ret)
+ return ret;
+
+ /* Initialize channels related values */
+ INIT_LIST_HEAD(&priv->ddev.channels);
+ lchan = &priv->lchan;
+ lchan->vchan.desc_free = ls2x_dma_desc_free;
+ vchan_init(&lchan->vchan, &priv->ddev);
+
+ return 0;
+}
+
+/*
+ * ls2x_dma_probe - Driver probe function
+ * @pdev: Pointer to the platform_device structure
+ *
+ * Return: '0' on success and failure value on error
+ */
+static int ls2x_dma_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct dma_device *ddev;
+ struct ls2x_dma_priv *priv;
+ struct device *dev = &pdev->dev;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->regs))
+ return dev_err_probe(dev, PTR_ERR(priv->regs),
+ "devm_platform_ioremap_resource failed.\n");
+
+ priv->dma_clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(priv->dma_clk))
+ return dev_err_probe(dev, PTR_ERR(priv->dma_clk), "devm_clk_get failed.\n");
+
+ ret = clk_prepare_enable(priv->dma_clk);
+ if (ret)
+ return dev_err_probe(dev, ret, "clk_prepare_enable failed.\n");
+
+ ret = ls2x_dma_chan_init(pdev, priv);
+ if (ret)
+ goto disable_clk;
+
+ ddev = &priv->ddev;
+ ddev->dev = dev;
+ dma_cap_zero(ddev->cap_mask);
+ dma_cap_set(DMA_SLAVE, ddev->cap_mask);
+ dma_cap_set(DMA_CYCLIC, ddev->cap_mask);
+
+ ddev->device_alloc_chan_resources = ls2x_dma_alloc_chan_resources;
+ ddev->device_free_chan_resources = ls2x_dma_free_chan_resources;
+ ddev->device_tx_status = dma_cookie_status;
+ ddev->device_issue_pending = ls2x_dma_issue_pending;
+ ddev->device_prep_slave_sg = ls2x_dma_prep_slave_sg;
+ ddev->device_prep_dma_cyclic = ls2x_dma_prep_dma_cyclic;
+ ddev->device_config = ls2x_dma_slave_config;
+ ddev->device_terminate_all = ls2x_dma_terminate_all;
+ ddev->device_synchronize = ls2x_dma_synchronize;
+ ddev->device_pause = ls2x_dma_pause;
+ ddev->device_resume = ls2x_dma_resume;
+
+ ddev->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ ddev->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ ddev->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+
+ ret = dma_async_device_register(&priv->ddev);
+ if (ret < 0)
+ goto disable_clk;
+
+ ret = of_dma_controller_register(dev->of_node, of_ls2x_dma_xlate, priv);
+ if (ret < 0)
+ goto unregister_dmac;
+
+ platform_set_drvdata(pdev, priv);
+
+ dev_info(dev, "Loongson LS2X APB DMA driver registered successfully.\n");
+ return 0;
+
+unregister_dmac:
+ dma_async_device_unregister(&priv->ddev);
+disable_clk:
+ clk_disable_unprepare(priv->dma_clk);
+
+ return ret;
+}
+
+/*
+ * ls2x_dma_remove - Driver remove function
+ * @pdev: Pointer to the platform_device structure
+ *
+ * Return: Always '0'
+ */
+static int ls2x_dma_remove(struct platform_device *pdev)
+{
+ struct ls2x_dma_priv *priv = platform_get_drvdata(pdev);
+
+ of_dma_controller_free(pdev->dev.of_node);
+ dma_async_device_unregister(&priv->ddev);
+ clk_disable_unprepare(priv->dma_clk);
+
+ return 0;
+}
+
+static const struct of_device_id ls2x_dma_of_match_table[] = {
+ { .compatible = "loongson,ls2k1000-apbdma" },
I think it can works with both 2k500 and 2k1000 without any distinction， use "loongson,ls2k-apbdma" maybe more suitable ?
