[PATCH v5 2/2] dmaengine: Loongson1: Add Loongson1 dmaengine driver

Keguang Zhang
2023-09-28T12:20:29Z

This patch adds DMA Engine driver for Loongson1 SoCs.

Signed-off-by: Keguang Zhang <keguang.zhang@gmail.com>
---
V4 -> V5:
Add DT support
Use DT data instead of platform data
Use chan_id of struct dma_chan instead of own id
Use of_dma_xlate_by_chan_id() instead of ls1x_dma_filter()
Update the author information to my official name
V3 -> V4:
Use dma_slave_map to find the proper channel.
Explicitly call devm_request_irq() and tasklet_kill().
Fix namespace issue.
Some minor fixes and cleanups.
V2 -> V3:
Rename ls1x_dma_filter_fn to ls1x_dma_filter.
V1 -> V2:
Change the config from 'DMA_LOONGSON1' to 'LOONGSON1_DMA',
and rearrange it in alphabetical order in Kconfig and Makefile.
Fix comment style.

drivers/dma/Kconfig | 9 +
drivers/dma/Makefile | 1 +
drivers/dma/loongson1-dma.c | 492 ++++++++++++++++++++++++++++++++++++
3 files changed, 502 insertions(+)
create mode 100644 drivers/dma/loongson1-dma.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 4ccae1a3b884..0b0d5c61b4a0 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -369,6 +369,15 @@ config K3_DMA
Support the DMA engine for Hisilicon K3 platform
devices.

+config LOONGSON1_DMA
+ tristate "Loongson1 DMA support"
+ depends on MACH_LOONGSON32
+ select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
+ help
+ This selects support for the DMA controller in Loongson1 SoCs,
+ which is required by Loongson1 NAND and AC97 support.
+
config LPC18XX_DMAMUX
bool "NXP LPC18xx/43xx DMA MUX for PL080"
depends on ARCH_LPC18XX || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 83553a97a010..887103db5ee3 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_INTEL_IDMA64) += idma64.o
obj-$(CONFIG_INTEL_IOATDMA) += ioat/
obj-y += idxd/
obj-$(CONFIG_K3_DMA) += k3dma.o
+obj-$(CONFIG_LOONGSON1_DMA) += loongson1-dma.o
obj-$(CONFIG_LPC18XX_DMAMUX) += lpc18xx-dmamux.o
obj-$(CONFIG_MILBEAUT_HDMAC) += milbeaut-hdmac.o
obj-$(CONFIG_MILBEAUT_XDMAC) += milbeaut-xdmac.o
diff --git a/drivers/dma/loongson1-dma.c b/drivers/dma/loongson1-dma.c
new file mode 100644
index 000000000000..b589103d5ae0
--- /dev/null
+++ b/drivers/dma/loongson1-dma.c
@@ -0,0 +1,492 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * DMA Driver for Loongson-1 SoC
+ *
+ * Copyright (C) 2015-2023 Keguang Zhang <keguang.zhang@gmail.com>
+ */
+
+#include <linux/dmapool.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "dmaengine.h"
+#include "virt-dma.h"
+
+/* Loongson 1 DMA Register Definitions */
+#define LS1X_DMA_CTRL 0x0
+
+/* DMA Control Register Bits */
+#define LS1X_DMA_STOP BIT(4)
+#define LS1X_DMA_START BIT(3)
+
+#define LS1X_DMA_ADDR_MASK GENMASK(31, 6)
+
+/* DMA Command Register Bits */
+#define LS1X_DMA_RAM2DEV BIT(12)
+#define LS1X_DMA_TRANS_OVER BIT(3)
+#define LS1X_DMA_SINGLE_TRANS_OVER BIT(2)
+#define LS1X_DMA_INT BIT(1)
+#define LS1X_DMA_INT_MASK BIT(0)
+
+#define LS1X_DMA_MAX_CHANNELS 3
+
+struct ls1x_dma_lli {
+ u32 next; /* next descriptor address */
+ u32 saddr; /* memory DMA address */
+ u32 daddr; /* device DMA address */
+ u32 length;
+ u32 stride;
+ u32 cycles;
+ u32 cmd;
+} __aligned(64);
+
+struct ls1x_dma_hwdesc {
+ struct ls1x_dma_lli *lli;
+ dma_addr_t phys;
+};
+
+struct ls1x_dma_desc {
+ struct virt_dma_desc vdesc;
+ struct ls1x_dma_chan *chan;
+
+ enum dma_transfer_direction dir;
+ enum dma_transaction_type type;
+
+ unsigned int nr_descs; /* number of descriptors */
+ unsigned int nr_done; /* number of completed descriptors */
+ struct ls1x_dma_hwdesc hwdesc[]; /* DMA coherent descriptors */
+};
+
+struct ls1x_dma_chan {
+ struct virt_dma_chan vchan;
+ struct dma_pool *desc_pool;
+ struct dma_slave_config cfg;
+
+ void __iomem *reg_base;
+ int irq;
+
+ struct ls1x_dma_desc *desc;
+};
+
+struct ls1x_dma {
+ struct dma_device ddev;
+ void __iomem *reg_base;
+
+ unsigned int nr_chans;
+ struct ls1x_dma_chan chan[];
+};
+
+#define to_ls1x_dma_chan(dchan) \
+ container_of(dchan, struct ls1x_dma_chan, vchan.chan)
+
+#define to_ls1x_dma_desc(vdesc) \
+ container_of(vdesc, struct ls1x_dma_desc, vdesc)
+
+/* macros for registers read/write */
+#define chan_readl(chan, off) \
+ readl((chan)->reg_base + (off))
+
+#define chan_writel(chan, off, val) \
+ writel((val), (chan)->reg_base + (off))
+
+static inline struct device *chan2dev(struct dma_chan *chan)
+{
+ return &chan->dev->device;
+}
+
+static void ls1x_dma_free_chan_resources(struct dma_chan *dchan)
+{
+ struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
+
+ vchan_free_chan_resources(&chan->vchan);
+ dma_pool_destroy(chan->desc_pool);
+ chan->desc_pool = NULL;
+}
+
+static int ls1x_dma_alloc_chan_resources(struct dma_chan *dchan)
+{
+ struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
+
+ chan->desc_pool = dma_pool_create(dma_chan_name(dchan),
+ dchan->device->dev,
+ sizeof(struct ls1x_dma_lli),
+ __alignof__(struct ls1x_dma_lli), 0);
+ if (!chan->desc_pool)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void ls1x_dma_free_desc(struct virt_dma_desc *vdesc)
+{
+ struct ls1x_dma_desc *desc = to_ls1x_dma_desc(vdesc);
+
+ if (desc->nr_descs) {
+ unsigned int i = desc->nr_descs;
+ struct ls1x_dma_hwdesc *hwdesc;
+
+ do {
+ hwdesc = &desc->hwdesc[--i];
+ dma_pool_free(desc->chan->desc_pool, hwdesc->lli,
+ hwdesc->phys);
+ } while (i);
+ }
+
+ kfree(desc);
+}
+
+static struct ls1x_dma_desc *ls1x_dma_alloc_desc(struct ls1x_dma_chan *chan,
+ int sg_len)
+{
+ struct ls1x_dma_desc *desc;
+
+ desc = kzalloc(struct_size(desc, hwdesc, sg_len), GFP_NOWAIT);
+
+ return desc;
+}
+
+static struct dma_async_tx_descriptor *
+ls1x_dma_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl,
+ unsigned int sg_len,
+ enum dma_transfer_direction direction,
+ unsigned long flags, void *context)
+{
+ struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
+ struct dma_slave_config *cfg = &chan->cfg;
+ struct ls1x_dma_desc *desc;
+ struct scatterlist *sg;
+ unsigned int dev_addr, bus_width, cmd, i;
+
+ if (!is_slave_direction(direction)) {
+ dev_err(chan2dev(dchan), "invalid DMA direction!\n");
+ return NULL;
+ }
+
+ dev_dbg(chan2dev(dchan), "sg_len=%d, dir=%s, flags=0x%lx\n", sg_len,
+ direction == DMA_MEM_TO_DEV ? "to device" : "from device",
+ flags);
+
+ switch (direction) {
+ case DMA_MEM_TO_DEV:
+ dev_addr = cfg->dst_addr;
+ bus_width = cfg->dst_addr_width;
+ cmd = LS1X_DMA_RAM2DEV | LS1X_DMA_INT;
+ break;
+ case DMA_DEV_TO_MEM:
+ dev_addr = cfg->src_addr;
+ bus_width = cfg->src_addr_width;
+ cmd = LS1X_DMA_INT;
+ break;
+ default:
+ dev_err(chan2dev(dchan),
+ "unsupported DMA transfer direction! %d\n", direction);
+ return NULL;
+ }
+
+ /* allocate DMA descriptor */
+ desc = ls1x_dma_alloc_desc(chan, sg_len);
+ if (!desc)
+ return NULL;
+
+ for_each_sg(sgl, sg, sg_len, i) {
+ dma_addr_t buf_addr = sg_dma_address(sg);
+ size_t buf_len = sg_dma_len(sg);
+ struct ls1x_dma_hwdesc *hwdesc = &desc->hwdesc[i];
+ struct ls1x_dma_lli *lli;
+
+ if (!is_dma_copy_aligned(dchan->device, buf_addr, 0, buf_len)) {
+ dev_err(chan2dev(dchan), "%s: buffer is not aligned!\n",
+ __func__);
+ goto err;
+ }
+
+ /* allocate HW DMA descriptors */
+ lli = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT,
+ &hwdesc->phys);
+ if (!lli) {
+ dev_err(chan2dev(dchan),
+ "%s: failed to alloc HW DMA descriptor!\n",
+ __func__);
+ goto err;
+ }
+ hwdesc->lli = lli;
+
+ /* config HW DMA descriptors */
+ lli->saddr = buf_addr;
+ lli->daddr = dev_addr;
+ lli->length = buf_len / bus_width;
+ lli->stride = 0;
+ lli->cycles = 1;
+ lli->cmd = cmd;
+ lli->next = 0;
+
+ if (i)
+ desc->hwdesc[i - 1].lli->next = hwdesc->phys;
+
+ dev_dbg(chan2dev(dchan),
+ "hwdesc=%px, saddr=%08x, daddr=%08x, length=%u\n",
+ hwdesc, buf_addr, dev_addr, buf_len);
+ }
+
+ /* config DMA descriptor */
+ desc->chan = chan;
+ desc->dir = direction;
+ desc->type = DMA_SLAVE;
+ desc->nr_descs = sg_len;
+ desc->nr_done = 0;
+
+ return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+err:
+ desc->nr_descs = i;
+ ls1x_dma_free_desc(&desc->vdesc);
+ return NULL;
+}
+
+static int ls1x_dma_slave_config(struct dma_chan *dchan,
+ struct dma_slave_config *config)
+{
+ struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
+
+ chan->cfg = *config;
+
+ return 0;
+}
+
+static int ls1x_dma_terminate_all(struct dma_chan *dchan)
+{
+ struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
+ unsigned long flags;
+ LIST_HEAD(head);
+
+ spin_lock_irqsave(&chan->vchan.lock, flags);
+
+ chan_writel(chan, LS1X_DMA_CTRL,
+ chan_readl(chan, LS1X_DMA_CTRL) | LS1X_DMA_STOP);
+ chan->desc = NULL;
+ vchan_get_all_descriptors(&chan->vchan, &head);
+
+ spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+ vchan_dma_desc_free_list(&chan->vchan, &head);
+
+ return 0;
+}
+
+static void ls1x_dma_trigger(struct ls1x_dma_chan *chan)
+{
+ struct dma_chan *dchan = &chan->vchan.chan;
+ struct ls1x_dma_desc *desc;
+ struct virt_dma_desc *vdesc;
+ unsigned int val;
+
+ vdesc = vchan_next_desc(&chan->vchan);
+ if (!vdesc) {
+ chan->desc = NULL;
+ return;
+ }
+ chan->desc = desc = to_ls1x_dma_desc(vdesc);
+
+ dev_dbg(chan2dev(dchan), "cookie=%d, %u descs, starting hwdesc=%px\n",
+ dchan->cookie, desc->nr_descs, &desc->hwdesc[0]);
+
+ val = desc->hwdesc[0].phys & LS1X_DMA_ADDR_MASK;
+ val |= dchan->chan_id;
+ val |= LS1X_DMA_START;
+ chan_writel(chan, LS1X_DMA_CTRL, val);
+}
+
+static void ls1x_dma_issue_pending(struct dma_chan *dchan)
+{
+ struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
+ unsigned long flags;
+
+ spin_lock_irqsave(&chan->vchan.lock, flags);
+
+ if (vchan_issue_pending(&chan->vchan) && !chan->desc)
+ ls1x_dma_trigger(chan);
+
+ spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static irqreturn_t ls1x_dma_irq_handler(int irq, void *data)
+{
+ struct ls1x_dma_chan *chan = data;
+ struct dma_chan *dchan = &chan->vchan.chan;
+
+ dev_dbg(chan2dev(dchan), "DMA IRQ %d on channel %d\n", irq,
+ dchan->chan_id);
+ if (!chan->desc) {
+ dev_warn(chan2dev(dchan),
+ "DMA IRQ with no active descriptor on channel %d\n",
+ dchan->chan_id);
+ return IRQ_NONE;
+ }
+
+ spin_lock(&chan->vchan.lock);
+
+ if (chan->desc->type == DMA_CYCLIC) {
+ vchan_cyclic_callback(&chan->desc->vdesc);
+ } else {
+ list_del(&chan->desc->vdesc.node);
+ vchan_cookie_complete(&chan->desc->vdesc);
+ chan->desc = NULL;
+ }
+
+ ls1x_dma_trigger(chan);
+
+ spin_unlock(&chan->vchan.lock);
+ return IRQ_HANDLED;
+}
+
+static int ls1x_dma_chan_probe(struct platform_device *pdev,
+ struct ls1x_dma *dma, int chan_id)
+{
+ struct device *dev = &pdev->dev;
+ struct ls1x_dma_chan *chan = &dma->chan[chan_id];
+ char pdev_irqname[4];
+ char *irqname;
+ int ret;
+
+ sprintf(pdev_irqname, "ch%u", chan_id);
+ chan->irq = platform_get_irq_byname(pdev, pdev_irqname);
+ if (chan->irq < 0)
+ return -ENODEV;
+
+ irqname = devm_kasprintf(dev, GFP_KERNEL, "%s:%s",
+ dev_name(dev), pdev_irqname);
+ if (!irqname)
+ return -ENOMEM;
+
+ ret = devm_request_irq(dev, chan->irq, ls1x_dma_irq_handler,
+ 0, irqname, chan);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "failed to request IRQ %u!\n", chan->irq);
+
+ chan->reg_base = dma->reg_base;
+ chan->vchan.desc_free = ls1x_dma_free_desc;
+ vchan_init(&chan->vchan, &dma->ddev);
+ dev_info(dev, "%s (irq %d) initialized\n", pdev_irqname, chan->irq);
+
+ return 0;
+}
+
+static void ls1x_dma_chan_remove(struct ls1x_dma *dma, int chan_id)
+{
+ struct device *dev = dma->ddev.dev;
+ struct ls1x_dma_chan *chan = &dma->chan[chan_id];
+
+ devm_free_irq(dev, chan->irq, chan);
+ list_del(&chan->vchan.chan.device_node);
+ tasklet_kill(&chan->vchan.task);
+}
+
+static int ls1x_dma_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct dma_device *ddev;
+ struct ls1x_dma *dma;
+ int nr_chans, ret, i;
+
+ nr_chans = platform_irq_count(pdev);
+ if (nr_chans <= 0)
+ return nr_chans;
+ if (nr_chans > LS1X_DMA_MAX_CHANNELS)
+ return dev_err_probe(dev, -EINVAL,
+ "nr_chans=%d exceeds the maximum\n",
+ nr_chans);
+
+ dma = devm_kzalloc(dev, struct_size(dma, chan, nr_chans), GFP_KERNEL);
+ if (!dma)
+ return -ENOMEM;
+
+ /* initialize DMA device */
+ dma->reg_base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(dma->reg_base))
+ return PTR_ERR(dma->reg_base);
+
+ ddev = &dma->ddev;
+ ddev->dev = dev;
+ ddev->copy_align = DMAENGINE_ALIGN_16_BYTES;
+ 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);
+ ddev->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+ ddev->device_alloc_chan_resources = ls1x_dma_alloc_chan_resources;
+ ddev->device_free_chan_resources = ls1x_dma_free_chan_resources;
+ ddev->device_prep_slave_sg = ls1x_dma_prep_slave_sg;
+ ddev->device_config = ls1x_dma_slave_config;
+ ddev->device_terminate_all = ls1x_dma_terminate_all;
+ ddev->device_tx_status = dma_cookie_status;
+ ddev->device_issue_pending = ls1x_dma_issue_pending;
+
+ dma_cap_set(DMA_SLAVE, ddev->cap_mask);
+ INIT_LIST_HEAD(&ddev->channels);
+
+ /* initialize DMA channels */
+ for (i = 0; i < nr_chans; i++) {
+ ret = ls1x_dma_chan_probe(pdev, dma, i);
+ if (ret)
+ return ret;
+ }
+ dma->nr_chans = nr_chans;
+
+ ret = dmaenginem_async_device_register(ddev);
+ if (ret) {
+ dev_err(dev, "failed to register DMA device! %d\n", ret);
+ return ret;
+ }
+
+ ret =
+ of_dma_controller_register(dev->of_node, of_dma_xlate_by_chan_id,
+ ddev);
+ if (ret) {
+ dev_err(dev, "failed to register DMA controller! %d\n", ret);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, dma);
+ dev_info(dev, "Loongson1 DMA driver registered\n");
+
+ return 0;
+}
+
+static int ls1x_dma_remove(struct platform_device *pdev)
+{
+ struct ls1x_dma *dma = platform_get_drvdata(pdev);
+ int i;
+
+ of_dma_controller_free(pdev->dev.of_node);
+
+ for (i = 0; i < dma->nr_chans; i++)
+ ls1x_dma_chan_remove(dma, i);
+
+ return 0;
+}
+
+static const struct of_device_id ls1x_dma_match[] = {
+ { .compatible = "loongson,ls1b-dma" },
+ { .compatible = "loongson,ls1c-dma" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ls1x_dma_match);
+
+static struct platform_driver ls1x_dma_driver = {
+ .probe = ls1x_dma_probe,
+ .remove = ls1x_dma_remove,
+ .driver = {
+ .name = "ls1x-dma",
+ .of_match_table = ls1x_dma_match,
+ },
+};
+
+module_platform_driver(ls1x_dma_driver);
+
+MODULE_AUTHOR("Keguang Zhang <keguang.zhang@gmail.com>");
+MODULE_DESCRIPTION("Loongson-1 DMA driver");
+MODULE_LICENSE("GPL");
--
2.39.2