Re: [PATCH v2 2/4] dmaengine: mtk_uart_dma: add Mediatek uart DMA support
From: Sean Wang <sean.wang@kernel.org>
Date: 2018-12-05 21:07:28
Also in:
dmaengine, linux-arm-kernel, linux-mediatek, linux-serial, lkml
. On Wed, Dec 5, 2018 at 1:31 AM Long Cheng [off-list ref] wrote:
quoted hunk ↗ jump to hunk
In DMA engine framework, add 8250 mtk dma to support it. Signed-off-by: Long Cheng <redacted> --- drivers/dma/mediatek/8250_mtk_dma.c | 894 +++++++++++++++++++++++++++++++++++ drivers/dma/mediatek/Kconfig | 11 + drivers/dma/mediatek/Makefile | 1 + 3 files changed, 906 insertions(+) create mode 100644 drivers/dma/mediatek/8250_mtk_dma.cdiff --git a/drivers/dma/mediatek/8250_mtk_dma.c b/drivers/dma/mediatek/8250_mtk_dma.c new file mode 100644 index 0000000..3454679 --- /dev/null +++ b/drivers/dma/mediatek/8250_mtk_dma.c@@ -0,0 +1,894 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Mediatek 8250 DMA driver. + * + * Copyright (c) 2018 MediaTek Inc. + * Author: Long Cheng <long.cheng@mediatek.com> + */ + +#include <linux/clk.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/of_dma.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/pm_runtime.h> +#include <linux/iopoll.h> + +#include "../virt-dma.h" + +#define MTK_APDMA_DEFAULT_REQUESTS 127 +#define MTK_APDMA_CHANNELS (CONFIG_SERIAL_8250_NR_UARTS * 2) + +#define VFF_EN_B BIT(0) +#define VFF_STOP_B BIT(0) +#define VFF_FLUSH_B BIT(0) +#define VFF_4G_SUPPORT_B BIT(0) +#define VFF_RX_INT_EN0_B BIT(0) /*rx valid size >= vff thre*/ +#define VFF_RX_INT_EN1_B BIT(1) +#define VFF_TX_INT_EN_B BIT(0) /*tx left size >= vff thre*/ +#define VFF_WARM_RST_B BIT(0) +#define VFF_RX_INT_FLAG_CLR_B (BIT(0) | BIT(1)) +#define VFF_TX_INT_FLAG_CLR_B 0 +#define VFF_STOP_CLR_B 0 +#define VFF_FLUSH_CLR_B 0 +#define VFF_INT_EN_CLR_B 0 +#define VFF_4G_SUPPORT_CLR_B 0 + +/* interrupt trigger level for tx */ +#define VFF_TX_THRE(n) ((n) * 7 / 8) +/* interrupt trigger level for rx */ +#define VFF_RX_THRE(n) ((n) * 3 / 4) + +#define MTK_DMA_RING_SIZE 0xffffU +/* invert this bit when wrap ring head again*/ +#define MTK_DMA_RING_WRAP 0x10000U + +#define VFF_INT_FLAG 0x00 +#define VFF_INT_EN 0x04 +#define VFF_EN 0x08 +#define VFF_RST 0x0c +#define VFF_STOP 0x10 +#define VFF_FLUSH 0x14 +#define VFF_ADDR 0x1c +#define VFF_LEN 0x24 +#define VFF_THRE 0x28 +#define VFF_WPT 0x2c +#define VFF_RPT 0x30 +/*TX: the buffer size HW can read. RX: the buffer size SW can read.*/ +#define VFF_VALID_SIZE 0x3c +/*TX: the buffer size SW can write. RX: the buffer size HW can write.*/ +#define VFF_LEFT_SIZE 0x40 +#define VFF_DEBUG_STATUS 0x50 +#define VFF_4G_SUPPORT 0x54 + +struct mtk_dmadev { + struct dma_device ddev; + void __iomem *mem_base[MTK_APDMA_CHANNELS]; + spinlock_t lock; /* dma dev lock */ + struct tasklet_struct task; + struct list_head pending; + struct clk *clk; + unsigned int dma_requests; + bool support_33bits; + unsigned int dma_irq[MTK_APDMA_CHANNELS]; + struct mtk_chan *ch[MTK_APDMA_CHANNELS]; +}; + +struct mtk_chan { + struct virt_dma_chan vc; + struct list_head node; + struct dma_slave_config cfg; + void __iomem *base; + struct mtk_dma_desc *desc; + + bool stop; + bool requested; + + unsigned int dma_sig;
the member can be removed as no real user would refer to it
+ unsigned int dma_ch;
a chan_id is already included in struct dma_chan, we can reuse it
+ unsigned int sgidx;
the member also can be removed as no real user would refer to it
+ unsigned int remain_size;
The member remain_size seems unnecessary data to maintain a channel. The virtual channel struct virt_dma_chan already provide the way to manage all descriptors you're operating on, you should reuse related functions to virt_dma_chan first. Or if you mean remain_size is about the remaining size of current descriptor, and then putting into struct mtk_dma_desc would be better.
+ unsigned int rx_ptr;
+};
+
+struct mtk_dma_sg {
+ dma_addr_t addr;
+ unsigned int en; /* number of elements (24-bit) */
+ unsigned int fn; /* number of frames (16-bit) */
+};
+
+struct mtk_dma_desc {
+ struct virt_dma_desc vd;
+ enum dma_transfer_direction dir;
+
+ unsigned int sglen;
+ struct mtk_dma_sg sg[0];
+};
+
+static bool mtk_dma_filter_fn(struct dma_chan *chan, void *param);
+static struct of_dma_filter_info mtk_dma_info = {
+ .filter_fn = mtk_dma_filter_fn,
+};
+
+static inline struct mtk_dmadev *to_mtk_dma_dev(struct dma_device *d)
+{
+ return container_of(d, struct mtk_dmadev, ddev);
+}
+
+static inline struct mtk_chan *to_mtk_dma_chan(struct dma_chan *c)
+{
+ return container_of(c, struct mtk_chan, vc.chan);
+}
+
+static inline struct mtk_dma_desc *to_mtk_dma_desc
+ (struct dma_async_tx_descriptor *t)
+{
+ return container_of(t, struct mtk_dma_desc, vd.tx);
+}
+
+static void mtk_dma_chan_write(struct mtk_chan *c,
+ unsigned int reg, unsigned int val)
+{
+ writel(val, c->base + reg);
+}
+
+static unsigned int mtk_dma_chan_read(struct mtk_chan *c, unsigned int reg)
+{
+ return readl(c->base + reg);
+}
+
+static void mtk_dma_desc_free(struct virt_dma_desc *vd)
+{
+ struct dma_chan *chan = vd->tx.chan;
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+
+ kfree(c->desc);
+ c->desc = NULL;
+}
+
+static int mtk_dma_clk_enable(struct mtk_dmadev *mtkd)
+{
+ int ret;
+
+ ret = clk_prepare_enable(mtkd->clk);
+ if (ret) {
+ dev_err(mtkd->ddev.dev, "Couldn't enable the clock\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static void mtk_dma_clk_disable(struct mtk_dmadev *mtkd)
+{
+ clk_disable_unprepare(mtkd->clk);
+}
+
+static void mtk_dma_remove_virt_list(dma_cookie_t cookie,
+ struct virt_dma_chan *vc)
+{
+ struct virt_dma_desc *vd;
+
+ if (list_empty(&vc->desc_issued) == 0) {
+ list_for_each_entry(vd, &vc->desc_issued, node) {
+ if (cookie == vd->tx.cookie) {
+ INIT_LIST_HEAD(&vc->desc_issued);generally, we don't force initialze the list desc_issued. Instead, when each descriptor is completed, we need to move each descriptor from the list desc_issued to the list desc_completed.
+ break;
+ }
+ }
+ }
+}
+
+static void mtk_dma_tx_flush(struct dma_chan *chan)
+{
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+
+ if (mtk_dma_chan_read(c, VFF_FLUSH) == 0U)
+ mtk_dma_chan_write(c, VFF_FLUSH, VFF_FLUSH_B);
+}
+
+static void mtk_dma_tx_write(struct dma_chan *chan)
+{
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+ unsigned int txcount = c->remain_size;
+ unsigned int len, send, left, wpt, wrap;
+
+ len = mtk_dma_chan_read(c, VFF_LEN);
+
+ while ((left = mtk_dma_chan_read(c, VFF_LEFT_SIZE)) > 0U) {
+ if (c->remain_size == 0U)
+ break;
+ send = min(left, c->remain_size);min_t
+ wpt = mtk_dma_chan_read(c, VFF_WPT); + wrap = wpt & MTK_DMA_RING_WRAP ? 0U : MTK_DMA_RING_WRAP; + + if ((wpt & (len - 1U)) + send < len) + mtk_dma_chan_write(c, VFF_WPT, wpt + send); + else + mtk_dma_chan_write(c, VFF_WPT, + ((wpt + send) & (len - 1U)) + | wrap); + + c->remain_size -= send;
I'm curious why you don't need to set up the hardware from the descriptor information
+ }
+
+ if (txcount != c->remain_size) {
+ mtk_dma_chan_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
+ mtk_dma_tx_flush(chan);
+ }
+}
+
+static void mtk_dma_start_tx(struct mtk_chan *c)
+{
+ if (mtk_dma_chan_read(c, VFF_LEFT_SIZE) == 0U)
+ mtk_dma_chan_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
+ else
+ mtk_dma_tx_write(&c->vc.chan);
+
+ c->stop = false;
+}
+
+static void mtk_dma_get_rx_size(struct mtk_chan *c)
+{
+ unsigned int rx_size = mtk_dma_chan_read(c, VFF_LEN);
+ unsigned int rdptr, wrptr, wrreg, rdreg, count;
+
+ rdreg = mtk_dma_chan_read(c, VFF_RPT);
+ wrreg = mtk_dma_chan_read(c, VFF_WPT);
+ rdptr = rdreg & MTK_DMA_RING_SIZE;
+ wrptr = wrreg & MTK_DMA_RING_SIZE;
+ count = ((rdreg ^ wrreg) & MTK_DMA_RING_WRAP) ?
+ (wrptr + rx_size - rdptr) : (wrptr - rdptr);
+
+ c->remain_size = count;
+ c->rx_ptr = rdptr;
+
+ mtk_dma_chan_write(c, VFF_RPT, wrreg);
+}
+
+static void mtk_dma_start_rx(struct mtk_chan *c)
+{
+ struct dma_chan *chan = &c->vc.chan;
+ struct mtk_dmadev *mtkd = to_mtk_dma_dev(chan->device);
+ struct mtk_dma_desc *d = c->desc;
+
+ if (mtk_dma_chan_read(c, VFF_VALID_SIZE) == 0U)
+ return;
+
+ if (d && d->vd.tx.cookie != 0) {the driver benefits from virtual_channel so you can manage the life cycle of each descriptor by the virtual channel related functions without handling details about the cookie.
+ mtk_dma_get_rx_size(c);
+ mtk_dma_remove_virt_list(d->vd.tx.cookie, &c->vc);
+ vchan_cookie_complete(&d->vd);
+ } else {
+ spin_lock(&mtkd->lock);
+ if (list_empty(&mtkd->pending))
+ list_add_tail(&c->node, &mtkd->pending);
+ spin_unlock(&mtkd->lock);
+ tasklet_schedule(&mtkd->task);
+ }
+}
+
+static void mtk_dma_reset(struct mtk_chan *c)
+{
+ struct mtk_dmadev *mtkd = to_mtk_dma_dev(c->vc.chan.device);
+ u32 status;
+ int ret;
+
+ mtk_dma_chan_write(c, VFF_ADDR, 0);
+ mtk_dma_chan_write(c, VFF_THRE, 0);
+ mtk_dma_chan_write(c, VFF_LEN, 0);
+ mtk_dma_chan_write(c, VFF_RST, VFF_WARM_RST_B);
+
+ ret = readx_poll_timeout(readl,
+ c->base + VFF_EN,
+ status, status == 0, 10, 100);
+ if (ret) {
+ dev_err(c->vc.chan.device->dev,
+ "dma reset: fail, timeout\n");
+ return;
+ }
+
+ if (c->cfg.direction == DMA_DEV_TO_MEM)
+ mtk_dma_chan_write(c, VFF_RPT, 0);
+ else if (c->cfg.direction == DMA_MEM_TO_DEV)
+ mtk_dma_chan_write(c, VFF_WPT, 0);
+
+ if (mtkd->support_33bits)
+ mtk_dma_chan_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
+}
+
+static void mtk_dma_stop(struct mtk_chan *c)
+{
+ u32 status;
+ int ret;
+
+ mtk_dma_chan_write(c, VFF_FLUSH, VFF_FLUSH_CLR_B);
+ /* Wait for flush */
+ ret = readx_poll_timeout(readl,
+ c->base + VFF_FLUSH,
+ status,
+ (status & VFF_FLUSH_B) != VFF_FLUSH_B,
+ 10, 100);
+ if (ret)
+ dev_err(c->vc.chan.device->dev,
+ "dma stop: polling FLUSH fail, DEBUG=0x%x\n",
+ mtk_dma_chan_read(c, VFF_DEBUG_STATUS));
+
+ /*set stop as 1 -> wait until en is 0 -> set stop as 0*/
+ mtk_dma_chan_write(c, VFF_STOP, VFF_STOP_B);
+ ret = readx_poll_timeout(readl,
+ c->base + VFF_EN,
+ status, status == 0, 10, 100);
+ if (ret)
+ dev_err(c->vc.chan.device->dev,
+ "dma stop: polling VFF_EN fail, DEBUG=0x%x\n",
+ mtk_dma_chan_read(c, VFF_DEBUG_STATUS));
+
+ mtk_dma_chan_write(c, VFF_STOP, VFF_STOP_CLR_B);
+ mtk_dma_chan_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
+
+ if (c->cfg.direction == DMA_DEV_TO_MEM)
+ mtk_dma_chan_write(c, VFF_INT_FLAG, VFF_RX_INT_FLAG_CLR_B);
+ else
+ mtk_dma_chan_write(c, VFF_INT_FLAG, VFF_TX_INT_FLAG_CLR_B);
+
+ c->stop = true;
+}
+
+/*
+ * This callback schedules all pending channels. We could be more
+ * clever here by postponing allocation of the real DMA channels to
+ * this point, and freeing them when our virtual channel becomes idle.
+ *
+ * We would then need to deal with 'all channels in-use'
+ */
+static void mtk_dma_sched(unsigned long data)
+{
+ struct mtk_dmadev *mtkd = (struct mtk_dmadev *)data;
+ struct virt_dma_desc *vd;
+ struct mtk_chan *c;
+ dma_cookie_t cookie;
+ unsigned long flags;
+ LIST_HEAD(head);
+
+ spin_lock_irq(&mtkd->lock);
+ list_splice_tail_init(&mtkd->pending, &head);
+ spin_unlock_irq(&mtkd->lock);
+
+ if (!list_empty(&head)) {
+ c = list_first_entry(&head, struct mtk_chan, node);
+ cookie = c->vc.chan.cookie;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ if (c->cfg.direction == DMA_DEV_TO_MEM) {
+ list_del_init(&c->node);
+ mtk_dma_start_rx(c);
+ } else if (c->cfg.direction == DMA_MEM_TO_DEV) {
+ vd = vchan_find_desc(&c->vc, cookie);
+ c->desc = to_mtk_dma_desc(&vd->tx);
+ list_del_init(&c->node);
+ mtk_dma_start_tx(c);
+ }
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+ }
+}
+
+static int mtk_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct mtk_dmadev *mtkd = to_mtk_dma_dev(chan->device);
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+ int ret = -EBUSY;
+
+ pm_runtime_get_sync(mtkd->ddev.dev);
+
+ if (!mtkd->ch[c->dma_ch]) {
+ c->base = mtkd->mem_base[c->dma_ch];
+ mtkd->ch[c->dma_ch] = c;
+ ret = 1;
+ }
+ c->requested = false;
+ mtk_dma_reset(c);
+
+ return ret;
+}
+
+static void mtk_dma_free_chan_resources(struct dma_chan *chan)
+{
+ struct mtk_dmadev *mtkd = to_mtk_dma_dev(chan->device);
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+
+ if (c->requested) {
+ c->requested = false;
+ free_irq(mtkd->dma_irq[c->dma_ch], chan);
+ }
+
+ tasklet_kill(&mtkd->task);
+ tasklet_kill(&c->vc.task);
+
+ c->base = NULL;
+ mtkd->ch[c->dma_ch] = NULL;
+ vchan_free_chan_resources(&c->vc);
+
+ dev_dbg(mtkd->ddev.dev, "freeing channel for %u\n", c->dma_sig);
+ c->dma_sig = 0;
+
+ pm_runtime_put_sync(mtkd->ddev.dev);
+}
+
+static enum dma_status mtk_dma_tx_status(struct dma_chan *chan,
+ dma_cookie_t cookie,
+ struct dma_tx_state *txstate)
+{
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+ enum dma_status ret;
+ unsigned long flags;
+
+ if (!txstate)
+ return DMA_ERROR;
+
+ ret = dma_cookie_status(chan, cookie, txstate);
+ spin_lock_irqsave(&c->vc.lock, flags);
+ if (ret == DMA_IN_PROGRESS) {
+ c->rx_ptr = mtk_dma_chan_read(c, VFF_RPT) & MTK_DMA_RING_SIZE;
+ dma_set_residue(txstate, c->rx_ptr);
+ } else if (ret == DMA_COMPLETE && c->cfg.direction == DMA_DEV_TO_MEM) {
+ dma_set_residue(txstate, c->remain_size);
+ } else {
+ dma_set_residue(txstate, 0);
+ }
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ return ret;
+}
+
+static struct dma_async_tx_descriptor *mtk_dma_prep_slave_sg
+ (struct dma_chan *chan, struct scatterlist *sgl,
+ unsigned int sglen, enum dma_transfer_direction dir,
+ unsigned long tx_flags, void *context)
+{
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+ struct scatterlist *sgent;
+ struct mtk_dma_desc *d;
+ struct mtk_dma_sg *sg;
+ unsigned int size, i, j, en;
+
+ en = 1;
+
+ if ((dir != DMA_DEV_TO_MEM) &&
+ (dir != DMA_MEM_TO_DEV)) {
+ dev_err(chan->device->dev, "bad direction\n");
+ return NULL;
+ }
+
+ /* Now allocate and setup the descriptor. */
+ d = kzalloc(sizeof(*d) + sglen * sizeof(d->sg[0]), GFP_ATOMIC);
+ if (!d)
+ return NULL;
+
+ d->dir = dir;
+
+ j = 0;
+ for_each_sg(sgl, sgent, sglen, i) {
+ d->sg[j].addr = sg_dma_address(sgent);
+ d->sg[j].en = en;
+ d->sg[j].fn = sg_dma_len(sgent) / en;
+ j++;
+ }
+
+ d->sglen = j;
+
+ if (dir == DMA_MEM_TO_DEV) {
+ for (size = i = 0; i < d->sglen; i++) {
+ sg = &d->sg[i];
+ size += sg->en * sg->fn;
+ }
+ c->remain_size = size;
+ }
+
+ return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
+}
+
+static void mtk_dma_issue_pending(struct dma_chan *chan)
+{
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+ struct virt_dma_desc *vd;
+ struct mtk_dmadev *mtkd;
+ dma_cookie_t cookie;
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ if (c->cfg.direction == DMA_DEV_TO_MEM) {
+ cookie = c->vc.chan.cookie;
+ mtkd = to_mtk_dma_dev(chan->device);
+ if (vchan_issue_pending(&c->vc) && !c->desc) {vchan_issue_pending means putting all the descriptors to list desc_issued, I'm supposed somewhere would iterate the list by vchan_next_desc and program each desc. into hardware. but I don't see the similar code.
+ vd = vchan_find_desc(&c->vc, cookie);
+ c->desc = to_mtk_dma_desc(&vd->tx);
+ }
+ } else if (c->cfg.direction == DMA_MEM_TO_DEV) {
+ cookie = c->vc.chan.cookie;
+ if (vchan_issue_pending(&c->vc) && !c->desc) {ditto as the above
+ vd = vchan_find_desc(&c->vc, cookie);
+ c->desc = to_mtk_dma_desc(&vd->tx);
+ mtk_dma_start_tx(c);
+ }
+ }
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+}
+
+static irqreturn_t mtk_dma_rx_interrupt(int irq, void *dev_id)
+{
+ struct dma_chan *chan = (struct dma_chan *)dev_id;
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ mtk_dma_chan_write(c, VFF_INT_FLAG, VFF_RX_INT_FLAG_CLR_B);
+
+ mtk_dma_start_rx(c);
+
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t mtk_dma_tx_interrupt(int irq, void *dev_id)
+{
+ struct dma_chan *chan = (struct dma_chan *)dev_id;
+ struct mtk_dmadev *mtkd = to_mtk_dma_dev(chan->device);
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+ struct mtk_dma_desc *d = c->desc;
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ if (c->remain_size != 0U) {
+ list_add_tail(&c->node, &mtkd->pending);
+ tasklet_schedule(&mtkd->task);
+ } else {
+ mtk_dma_remove_virt_list(d->vd.tx.cookie, &c->vc);
+ vchan_cookie_complete(&d->vd);
+ }
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ mtk_dma_chan_write(c, VFF_INT_FLAG, VFF_TX_INT_FLAG_CLR_B);
+
+ return IRQ_HANDLED;
+}
+
+static int mtk_dma_slave_config(struct dma_chan *chan,
+ struct dma_slave_config *cfg)
+{
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+ struct mtk_dmadev *mtkd = to_mtk_dma_dev(c->vc.chan.device);
+ int ret;
+
+ c->cfg = *cfg;
+
+ if (cfg->direction == DMA_DEV_TO_MEM) {
+ unsigned int rx_len = cfg->src_addr_width * 1024;
+
+ mtk_dma_chan_write(c, VFF_ADDR, cfg->src_addr);
+ mtk_dma_chan_write(c, VFF_LEN, rx_len);
+ mtk_dma_chan_write(c, VFF_THRE, VFF_RX_THRE(rx_len));
+ mtk_dma_chan_write(c,
+ VFF_INT_EN, VFF_RX_INT_EN0_B
+ | VFF_RX_INT_EN1_B);
+ mtk_dma_chan_write(c, VFF_INT_FLAG, VFF_RX_INT_FLAG_CLR_B);
+ mtk_dma_chan_write(c, VFF_EN, VFF_EN_B);
+
+ if (!c->requested) {
+ c->requested = true;
+ ret = request_irq(mtkd->dma_irq[c->dma_ch],
+ mtk_dma_rx_interrupt,
+ IRQF_TRIGGER_NONE,
+ KBUILD_MODNAME, chan);
+ if (ret < 0) {
+ dev_err(chan->device->dev, "Can't request rx dma IRQ\n");
+ return -EINVAL;
+ }
+ }
+ } else if (cfg->direction == DMA_MEM_TO_DEV) {
+ unsigned int tx_len = cfg->dst_addr_width * 1024;
+
+ mtk_dma_chan_write(c, VFF_ADDR, cfg->dst_addr);
+ mtk_dma_chan_write(c, VFF_LEN, tx_len);
+ mtk_dma_chan_write(c, VFF_THRE, VFF_TX_THRE(tx_len));
+ mtk_dma_chan_write(c, VFF_INT_FLAG, VFF_TX_INT_FLAG_CLR_B);
+ mtk_dma_chan_write(c, VFF_EN, VFF_EN_B);
+
+ if (!c->requested) {
+ c->requested = true;
+ ret = request_irq(mtkd->dma_irq[c->dma_ch],
+ mtk_dma_tx_interrupt,
+ IRQF_TRIGGER_NONE,
+ KBUILD_MODNAME, chan);
+ if (ret < 0) {
+ dev_err(chan->device->dev, "Can't request tx dma IRQ\n");
+ return -EINVAL;
+ }
+ }
+ }
+
+ if (mtkd->support_33bits)
+ mtk_dma_chan_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_B);
+
+ if (mtk_dma_chan_read(c, VFF_EN) != VFF_EN_B) {
+ dev_err(chan->device->dev,
+ "config dma dir[%d] fail\n", cfg->direction);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int mtk_dma_terminate_all(struct dma_chan *chan)
+{
+ struct mtk_chan *c = to_mtk_dma_chan(chan);
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ list_del_init(&c->node);
+ mtk_dma_stop(c);
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ return 0;
+}
+
+static int mtk_dma_device_pause(struct dma_chan *chan)
+{
+ /* just for check caps pass */
+ return -EINVAL;
+}it it possible not to register the function to the core if the hardware doesn't support it?
+
+static int mtk_dma_device_resume(struct dma_chan *chan)
+{
+ /* just for check caps pass */
+ return -EINVAL;
+}ditto as the above
+
+static void mtk_dma_free(struct mtk_dmadev *mtkd)
+{
+ tasklet_kill(&mtkd->task);
+ while (list_empty(&mtkd->ddev.channels) == 0) {
+ struct mtk_chan *c = list_first_entry(&mtkd->ddev.channels,
+ struct mtk_chan, vc.chan.device_node);
+
+ list_del(&c->vc.chan.device_node);
+ tasklet_kill(&c->vc.task);
+ devm_kfree(mtkd->ddev.dev, c);
+ }
+}
+
+static const struct of_device_id mtk_uart_dma_match[] = {
+ { .compatible = "mediatek,mt6577-uart-dma", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, mtk_uart_dma_match);
+
+static int mtk_apdma_probe(struct platform_device *pdev)
+{
+ struct mtk_dmadev *mtkd;
+ struct resource *res;
+ struct mtk_chan *c;
+ unsigned int i;
+ int rc;
+
+ mtkd = devm_kzalloc(&pdev->dev, sizeof(*mtkd), GFP_KERNEL);
+ if (!mtkd)
+ return -ENOMEM;
+
+ for (i = 0; i < MTK_APDMA_CHANNELS; i++) {
+ res = platform_get_resource(pdev, IORESOURCE_MEM, i);
+ if (!res)
+ return -ENODEV;
+ mtkd->mem_base[i] = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(mtkd->mem_base[i]))
+ return PTR_ERR(mtkd->mem_base[i]);
+ }
+
+ for (i = 0; i < MTK_APDMA_CHANNELS; i++) {
+ mtkd->dma_irq[i] = platform_get_irq(pdev, i);
+ if ((int)mtkd->dma_irq[i] < 0) {
+ dev_err(&pdev->dev, "failed to get IRQ[%d]\n", i);
+ return -EINVAL;
+ }
+ }
+
+ mtkd->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(mtkd->clk)) {
+ dev_err(&pdev->dev, "No clock specified\n");
+ return PTR_ERR(mtkd->clk);
+ }
+
+ if (of_property_read_bool(pdev->dev.of_node, "dma-33bits")) {
+ dev_info(&pdev->dev, "Support dma 33bits\n");
+ mtkd->support_33bits = true;
+ }
+
+ if (mtkd->support_33bits)
+ rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(33));
+ else
+ rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+ if (rc)
+ return rc;
+
+ dma_cap_set(DMA_SLAVE, mtkd->ddev.cap_mask);
+ mtkd->ddev.device_alloc_chan_resources = mtk_dma_alloc_chan_resources;
+ mtkd->ddev.device_free_chan_resources = mtk_dma_free_chan_resources;
+ mtkd->ddev.device_tx_status = mtk_dma_tx_status;
+ mtkd->ddev.device_issue_pending = mtk_dma_issue_pending;
+ mtkd->ddev.device_prep_slave_sg = mtk_dma_prep_slave_sg;
+ mtkd->ddev.device_config = mtk_dma_slave_config;
+ mtkd->ddev.device_pause = mtk_dma_device_pause;
+ mtkd->ddev.device_resume = mtk_dma_device_resume;
+ mtkd->ddev.device_terminate_all = mtk_dma_terminate_all;
+ mtkd->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+ mtkd->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+ mtkd->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+ mtkd->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+ mtkd->ddev.dev = &pdev->dev;
+ INIT_LIST_HEAD(&mtkd->ddev.channels);
+ INIT_LIST_HEAD(&mtkd->pending);
+
+ spin_lock_init(&mtkd->lock);
+ tasklet_init(&mtkd->task, mtk_dma_sched, (unsigned long)mtkd);
+
+ mtkd->dma_requests = MTK_APDMA_DEFAULT_REQUESTS;
+ if (of_property_read_u32(pdev->dev.of_node,
+ "dma-requests", &mtkd->dma_requests)) {
+ dev_info(&pdev->dev,
+ "Missing dma-requests property, using %u.\n",
+ MTK_APDMA_DEFAULT_REQUESTS);
+ }
+
+ for (i = 0; i < MTK_APDMA_CHANNELS; i++) {
+ c = devm_kzalloc(mtkd->ddev.dev, sizeof(*c), GFP_KERNEL);
+ if (!c)
+ goto err_no_dma;
+
+ c->vc.desc_free = mtk_dma_desc_free;
+ vchan_init(&c->vc, &mtkd->ddev);
+ INIT_LIST_HEAD(&c->node);
+ }
+
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_set_active(&pdev->dev);
+
+ rc = dma_async_device_register(&mtkd->ddev);
+ if (rc)
+ goto rpm_disable;
+
+ platform_set_drvdata(pdev, mtkd);
+
+ if (pdev->dev.of_node) {
+ mtk_dma_info.dma_cap = mtkd->ddev.cap_mask;
+
+ /* Device-tree DMA controller registration */
+ rc = of_dma_controller_register(pdev->dev.of_node,
+ of_dma_simple_xlate,
+ &mtk_dma_info);reusing of_dma_xlate_by_chan_id seem that also work for you.
quoted hunk ↗ jump to hunk
+ if (rc) + goto dma_remove; + } + + return rc; + +dma_remove: + dma_async_device_unregister(&mtkd->ddev); +rpm_disable: + pm_runtime_disable(&pdev->dev); +err_no_dma: + mtk_dma_free(mtkd); + return rc; +} + +static int mtk_apdma_remove(struct platform_device *pdev) +{ + struct mtk_dmadev *mtkd = platform_get_drvdata(pdev); + + if (pdev->dev.of_node) + of_dma_controller_free(pdev->dev.of_node); + + pm_runtime_disable(&pdev->dev); + pm_runtime_put_noidle(&pdev->dev); + + dma_async_device_unregister(&mtkd->ddev); + + mtk_dma_free(mtkd); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int mtk_dma_suspend(struct device *dev) +{ + struct mtk_dmadev *mtkd = dev_get_drvdata(dev); + + if (!pm_runtime_suspended(dev)) + mtk_dma_clk_disable(mtkd); + + return 0; +} + +static int mtk_dma_resume(struct device *dev) +{ + int ret; + struct mtk_dmadev *mtkd = dev_get_drvdata(dev); + + if (!pm_runtime_suspended(dev)) { + ret = mtk_dma_clk_enable(mtkd); + if (ret) + return ret; + } + + return 0; +} + +static int mtk_dma_runtime_suspend(struct device *dev) +{ + struct mtk_dmadev *mtkd = dev_get_drvdata(dev); + + mtk_dma_clk_disable(mtkd); + + return 0; +} + +static int mtk_dma_runtime_resume(struct device *dev) +{ + int ret; + struct mtk_dmadev *mtkd = dev_get_drvdata(dev); + + ret = mtk_dma_clk_enable(mtkd); + if (ret) + return ret; + + return 0; +} + +#endif /* CONFIG_PM_SLEEP */ + +static const struct dev_pm_ops mtk_dma_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(mtk_dma_suspend, mtk_dma_resume) + SET_RUNTIME_PM_OPS(mtk_dma_runtime_suspend, + mtk_dma_runtime_resume, NULL) +}; + +static struct platform_driver mtk_dma_driver = { + .probe = mtk_apdma_probe, + .remove = mtk_apdma_remove, + .driver = { + .name = KBUILD_MODNAME, + .pm = &mtk_dma_pm_ops, + .of_match_table = of_match_ptr(mtk_uart_dma_match), + }, +}; + +static bool mtk_dma_filter_fn(struct dma_chan *chan, void *param) +{ + if (chan->device->dev->driver == &mtk_dma_driver.driver) { + struct mtk_dmadev *mtkd = to_mtk_dma_dev(chan->device); + struct mtk_chan *c = to_mtk_dma_chan(chan); + unsigned int req = *(unsigned int *)param; + + if (req <= mtkd->dma_requests) { + c->dma_sig = req; + c->dma_ch = req; + return true; + } + } + return false; +} + +module_platform_driver(mtk_dma_driver); + +MODULE_DESCRIPTION("MediaTek UART APDMA Controller Driver"); +MODULE_AUTHOR("Long Cheng [off-list ref]"); +MODULE_LICENSE("GPL v2"); +diff --git a/drivers/dma/mediatek/Kconfig b/drivers/dma/mediatek/Kconfig index 27bac0b..bef436e 100644 --- a/drivers/dma/mediatek/Kconfig +++ b/drivers/dma/mediatek/Kconfig@@ -1,4 +1,15 @@ +config DMA_MTK_UART + tristate "MediaTek SoCs APDMA support for UART" + depends on OF + select DMA_ENGINE + select DMA_VIRTUAL_CHANNELS + help + Support for the UART DMA engine found on MediaTek MTK SoCs. + when 8250 mtk uart is enabled, and if you want to using DMA, + you can enable the config. the DMA engine just only be used + with MediaTek Socs. + config MTK_HSDMA tristate "MediaTek High-Speed DMA controller support" depends on ARCH_MEDIATEK || COMPILE_TESTdiff --git a/drivers/dma/mediatek/Makefile b/drivers/dma/mediatek/Makefile index 6e778f8..2f2efd9 100644 --- a/drivers/dma/mediatek/Makefile +++ b/drivers/dma/mediatek/Makefile@@ -1 +1,2 @@ +obj-$(CONFIG_DMA_MTK_UART) += 8250_mtk_dma.o obj-$(CONFIG_MTK_HSDMA) += mtk-hsdma.o --1.7.9.5 _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek