linux-stable/drivers/dma/mediatek/mtk-uart-apdma.c
Guillaume Ranquet 9041575348 dmaengine: mediatek: use GFP_NOWAIT instead of GFP_ATOMIC in prep_dma
As recommended by the doc in:
Documentation/drivers-api/dmaengine/provider.rst

Use GFP_NOWAIT to not deplete the emergency pool.

Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>

Link: https://lore.kernel.org/r/20210513192642.29446-4-granquet@baylibre.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2021-06-07 12:23:47 +05:30

654 lines
16 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* MediaTek UART APDMA driver.
*
* Copyright (c) 2019 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/iopoll.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/of_dma.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "../virt-dma.h"
/* The default number of virtual channel */
#define MTK_UART_APDMA_NR_VCHANS 8
#define VFF_EN_B BIT(0)
#define VFF_STOP_B BIT(0)
#define VFF_FLUSH_B BIT(0)
#define VFF_4G_EN_B BIT(0)
/* rx valid size >= vff thre */
#define VFF_RX_INT_EN_B (BIT(0) | BIT(1))
/* tx left size >= vff thre */
#define VFF_TX_INT_EN_B BIT(0)
#define VFF_WARM_RST_B BIT(0)
#define VFF_RX_INT_CLR_B (BIT(0) | BIT(1))
#define VFF_TX_INT_CLR_B 0
#define VFF_STOP_CLR_B 0
#define VFF_EN_CLR_B 0
#define VFF_INT_EN_CLR_B 0
#define VFF_4G_SUPPORT_CLR_B 0
/*
* interrupt trigger level for tx
* if threshold is n, no polling is required to start tx.
* otherwise need polling VFF_FLUSH.
*/
#define VFF_TX_THRE(n) (n)
/* interrupt trigger level for rx */
#define VFF_RX_THRE(n) ((n) * 3 / 4)
#define VFF_RING_SIZE 0xffff
/* invert this bit when wrap ring head again */
#define VFF_RING_WRAP 0x10000
#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_uart_apdmadev {
struct dma_device ddev;
struct clk *clk;
bool support_33bits;
unsigned int dma_requests;
};
struct mtk_uart_apdma_desc {
struct virt_dma_desc vd;
dma_addr_t addr;
unsigned int avail_len;
};
struct mtk_chan {
struct virt_dma_chan vc;
struct dma_slave_config cfg;
struct mtk_uart_apdma_desc *desc;
enum dma_transfer_direction dir;
void __iomem *base;
unsigned int irq;
unsigned int rx_status;
};
static inline struct mtk_uart_apdmadev *
to_mtk_uart_apdma_dev(struct dma_device *d)
{
return container_of(d, struct mtk_uart_apdmadev, ddev);
}
static inline struct mtk_chan *to_mtk_uart_apdma_chan(struct dma_chan *c)
{
return container_of(c, struct mtk_chan, vc.chan);
}
static inline struct mtk_uart_apdma_desc *to_mtk_uart_apdma_desc
(struct dma_async_tx_descriptor *t)
{
return container_of(t, struct mtk_uart_apdma_desc, vd.tx);
}
static void mtk_uart_apdma_write(struct mtk_chan *c,
unsigned int reg, unsigned int val)
{
writel(val, c->base + reg);
}
static unsigned int mtk_uart_apdma_read(struct mtk_chan *c, unsigned int reg)
{
return readl(c->base + reg);
}
static void mtk_uart_apdma_desc_free(struct virt_dma_desc *vd)
{
kfree(container_of(vd, struct mtk_uart_apdma_desc, vd));
}
static void mtk_uart_apdma_start_tx(struct mtk_chan *c)
{
struct mtk_uart_apdmadev *mtkd =
to_mtk_uart_apdma_dev(c->vc.chan.device);
struct mtk_uart_apdma_desc *d = c->desc;
unsigned int wpt, vff_sz;
vff_sz = c->cfg.dst_port_window_size;
if (!mtk_uart_apdma_read(c, VFF_LEN)) {
mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
mtk_uart_apdma_write(c, VFF_THRE, VFF_TX_THRE(vff_sz));
mtk_uart_apdma_write(c, VFF_WPT, 0);
mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
if (mtkd->support_33bits)
mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
}
mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
dev_err(c->vc.chan.device->dev, "Enable TX fail\n");
if (!mtk_uart_apdma_read(c, VFF_LEFT_SIZE)) {
mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
return;
}
wpt = mtk_uart_apdma_read(c, VFF_WPT);
wpt += c->desc->avail_len;
if ((wpt & VFF_RING_SIZE) == vff_sz)
wpt = (wpt & VFF_RING_WRAP) ^ VFF_RING_WRAP;
/* Let DMA start moving data */
mtk_uart_apdma_write(c, VFF_WPT, wpt);
/* HW auto set to 0 when left size >= threshold */
mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
if (!mtk_uart_apdma_read(c, VFF_FLUSH))
mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
}
static void mtk_uart_apdma_start_rx(struct mtk_chan *c)
{
struct mtk_uart_apdmadev *mtkd =
to_mtk_uart_apdma_dev(c->vc.chan.device);
struct mtk_uart_apdma_desc *d = c->desc;
unsigned int vff_sz;
vff_sz = c->cfg.src_port_window_size;
if (!mtk_uart_apdma_read(c, VFF_LEN)) {
mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
mtk_uart_apdma_write(c, VFF_THRE, VFF_RX_THRE(vff_sz));
mtk_uart_apdma_write(c, VFF_RPT, 0);
mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
if (mtkd->support_33bits)
mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
}
mtk_uart_apdma_write(c, VFF_INT_EN, VFF_RX_INT_EN_B);
mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
dev_err(c->vc.chan.device->dev, "Enable RX fail\n");
}
static void mtk_uart_apdma_tx_handler(struct mtk_chan *c)
{
mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
}
static void mtk_uart_apdma_rx_handler(struct mtk_chan *c)
{
struct mtk_uart_apdma_desc *d = c->desc;
unsigned int len, wg, rg;
int cnt;
mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
if (!mtk_uart_apdma_read(c, VFF_VALID_SIZE))
return;
mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
len = c->cfg.src_port_window_size;
rg = mtk_uart_apdma_read(c, VFF_RPT);
wg = mtk_uart_apdma_read(c, VFF_WPT);
cnt = (wg & VFF_RING_SIZE) - (rg & VFF_RING_SIZE);
/*
* The buffer is ring buffer. If wrap bit different,
* represents the start of the next cycle for WPT
*/
if ((rg ^ wg) & VFF_RING_WRAP)
cnt += len;
c->rx_status = d->avail_len - cnt;
mtk_uart_apdma_write(c, VFF_RPT, wg);
}
static void mtk_uart_apdma_chan_complete_handler(struct mtk_chan *c)
{
struct mtk_uart_apdma_desc *d = c->desc;
if (d) {
list_del(&d->vd.node);
vchan_cookie_complete(&d->vd);
c->desc = NULL;
}
}
static irqreturn_t mtk_uart_apdma_irq_handler(int irq, void *dev_id)
{
struct dma_chan *chan = (struct dma_chan *)dev_id;
struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
unsigned long flags;
spin_lock_irqsave(&c->vc.lock, flags);
if (c->dir == DMA_DEV_TO_MEM)
mtk_uart_apdma_rx_handler(c);
else if (c->dir == DMA_MEM_TO_DEV)
mtk_uart_apdma_tx_handler(c);
mtk_uart_apdma_chan_complete_handler(c);
spin_unlock_irqrestore(&c->vc.lock, flags);
return IRQ_HANDLED;
}
static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)
{
struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
unsigned int status;
int ret;
ret = pm_runtime_get_sync(mtkd->ddev.dev);
if (ret < 0) {
pm_runtime_put_noidle(chan->device->dev);
return ret;
}
mtk_uart_apdma_write(c, VFF_ADDR, 0);
mtk_uart_apdma_write(c, VFF_THRE, 0);
mtk_uart_apdma_write(c, VFF_LEN, 0);
mtk_uart_apdma_write(c, VFF_RST, VFF_WARM_RST_B);
ret = readx_poll_timeout(readl, c->base + VFF_EN,
status, !status, 10, 100);
if (ret)
return ret;
ret = request_irq(c->irq, mtk_uart_apdma_irq_handler,
IRQF_TRIGGER_NONE, KBUILD_MODNAME, chan);
if (ret < 0) {
dev_err(chan->device->dev, "Can't request dma IRQ\n");
return -EINVAL;
}
if (mtkd->support_33bits)
mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
return ret;
}
static void mtk_uart_apdma_free_chan_resources(struct dma_chan *chan)
{
struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
free_irq(c->irq, chan);
tasklet_kill(&c->vc.task);
vchan_free_chan_resources(&c->vc);
pm_runtime_put_sync(mtkd->ddev.dev);
}
static enum dma_status mtk_uart_apdma_tx_status(struct dma_chan *chan,
dma_cookie_t cookie,
struct dma_tx_state *txstate)
{
struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
enum dma_status ret;
ret = dma_cookie_status(chan, cookie, txstate);
if (!txstate)
return ret;
dma_set_residue(txstate, c->rx_status);
return ret;
}
/*
* dmaengine_prep_slave_single will call the function. and sglen is 1.
* 8250 uart using one ring buffer, and deal with one sg.
*/
static struct dma_async_tx_descriptor *mtk_uart_apdma_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_uart_apdma_chan(chan);
struct mtk_uart_apdma_desc *d;
if (!is_slave_direction(dir) || sglen != 1)
return NULL;
/* Now allocate and setup the descriptor */
d = kzalloc(sizeof(*d), GFP_NOWAIT);
if (!d)
return NULL;
d->avail_len = sg_dma_len(sgl);
d->addr = sg_dma_address(sgl);
c->dir = dir;
return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
}
static void mtk_uart_apdma_issue_pending(struct dma_chan *chan)
{
struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
struct virt_dma_desc *vd;
unsigned long flags;
spin_lock_irqsave(&c->vc.lock, flags);
if (vchan_issue_pending(&c->vc) && !c->desc) {
vd = vchan_next_desc(&c->vc);
c->desc = to_mtk_uart_apdma_desc(&vd->tx);
if (c->dir == DMA_DEV_TO_MEM)
mtk_uart_apdma_start_rx(c);
else if (c->dir == DMA_MEM_TO_DEV)
mtk_uart_apdma_start_tx(c);
}
spin_unlock_irqrestore(&c->vc.lock, flags);
}
static int mtk_uart_apdma_slave_config(struct dma_chan *chan,
struct dma_slave_config *config)
{
struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
memcpy(&c->cfg, config, sizeof(*config));
return 0;
}
static int mtk_uart_apdma_terminate_all(struct dma_chan *chan)
{
struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
unsigned long flags;
unsigned int status;
LIST_HEAD(head);
int ret;
mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
ret = readx_poll_timeout(readl, c->base + VFF_FLUSH,
status, status != VFF_FLUSH_B, 10, 100);
if (ret)
dev_err(c->vc.chan.device->dev, "flush: fail, status=0x%x\n",
mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
/*
* Stop need 3 steps.
* 1. set stop to 1
* 2. wait en to 0
* 3. set stop as 0
*/
mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_B);
ret = readx_poll_timeout(readl, c->base + VFF_EN,
status, !status, 10, 100);
if (ret)
dev_err(c->vc.chan.device->dev, "stop: fail, status=0x%x\n",
mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_CLR_B);
mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
if (c->dir == DMA_DEV_TO_MEM)
mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
else if (c->dir == DMA_MEM_TO_DEV)
mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
synchronize_irq(c->irq);
spin_lock_irqsave(&c->vc.lock, flags);
vchan_get_all_descriptors(&c->vc, &head);
spin_unlock_irqrestore(&c->vc.lock, flags);
vchan_dma_desc_free_list(&c->vc, &head);
return 0;
}
static int mtk_uart_apdma_device_pause(struct dma_chan *chan)
{
struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
unsigned long flags;
spin_lock_irqsave(&c->vc.lock, flags);
mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
synchronize_irq(c->irq);
spin_unlock_irqrestore(&c->vc.lock, flags);
return 0;
}
static void mtk_uart_apdma_free(struct mtk_uart_apdmadev *mtkd)
{
while (!list_empty(&mtkd->ddev.channels)) {
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);
}
}
static const struct of_device_id mtk_uart_apdma_match[] = {
{ .compatible = "mediatek,mt6577-uart-dma", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, mtk_uart_apdma_match);
static int mtk_uart_apdma_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct mtk_uart_apdmadev *mtkd;
int bit_mask = 32, rc;
struct mtk_chan *c;
unsigned int i;
mtkd = devm_kzalloc(&pdev->dev, sizeof(*mtkd), GFP_KERNEL);
if (!mtkd)
return -ENOMEM;
mtkd->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(mtkd->clk)) {
dev_err(&pdev->dev, "No clock specified\n");
rc = PTR_ERR(mtkd->clk);
return rc;
}
if (of_property_read_bool(np, "mediatek,dma-33bits"))
mtkd->support_33bits = true;
if (mtkd->support_33bits)
bit_mask = 33;
rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(bit_mask));
if (rc)
return rc;
dma_cap_set(DMA_SLAVE, mtkd->ddev.cap_mask);
mtkd->ddev.device_alloc_chan_resources =
mtk_uart_apdma_alloc_chan_resources;
mtkd->ddev.device_free_chan_resources =
mtk_uart_apdma_free_chan_resources;
mtkd->ddev.device_tx_status = mtk_uart_apdma_tx_status;
mtkd->ddev.device_issue_pending = mtk_uart_apdma_issue_pending;
mtkd->ddev.device_prep_slave_sg = mtk_uart_apdma_prep_slave_sg;
mtkd->ddev.device_config = mtk_uart_apdma_slave_config;
mtkd->ddev.device_pause = mtk_uart_apdma_device_pause;
mtkd->ddev.device_terminate_all = mtk_uart_apdma_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);
mtkd->dma_requests = MTK_UART_APDMA_NR_VCHANS;
if (of_property_read_u32(np, "dma-requests", &mtkd->dma_requests)) {
dev_info(&pdev->dev,
"Using %u as missing dma-requests property\n",
MTK_UART_APDMA_NR_VCHANS);
}
for (i = 0; i < mtkd->dma_requests; i++) {
c = devm_kzalloc(mtkd->ddev.dev, sizeof(*c), GFP_KERNEL);
if (!c) {
rc = -ENODEV;
goto err_no_dma;
}
c->base = devm_platform_ioremap_resource(pdev, i);
if (IS_ERR(c->base)) {
rc = PTR_ERR(c->base);
goto err_no_dma;
}
c->vc.desc_free = mtk_uart_apdma_desc_free;
vchan_init(&c->vc, &mtkd->ddev);
rc = platform_get_irq(pdev, i);
if (rc < 0)
goto err_no_dma;
c->irq = rc;
}
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);
/* Device-tree DMA controller registration */
rc = of_dma_controller_register(np, of_dma_xlate_by_chan_id, mtkd);
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_uart_apdma_free(mtkd);
return rc;
}
static int mtk_uart_apdma_remove(struct platform_device *pdev)
{
struct mtk_uart_apdmadev *mtkd = platform_get_drvdata(pdev);
of_dma_controller_free(pdev->dev.of_node);
mtk_uart_apdma_free(mtkd);
dma_async_device_unregister(&mtkd->ddev);
pm_runtime_disable(&pdev->dev);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int mtk_uart_apdma_suspend(struct device *dev)
{
struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
if (!pm_runtime_suspended(dev))
clk_disable_unprepare(mtkd->clk);
return 0;
}
static int mtk_uart_apdma_resume(struct device *dev)
{
int ret;
struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
if (!pm_runtime_suspended(dev)) {
ret = clk_prepare_enable(mtkd->clk);
if (ret)
return ret;
}
return 0;
}
#endif /* CONFIG_PM_SLEEP */
#ifdef CONFIG_PM
static int mtk_uart_apdma_runtime_suspend(struct device *dev)
{
struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
clk_disable_unprepare(mtkd->clk);
return 0;
}
static int mtk_uart_apdma_runtime_resume(struct device *dev)
{
struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
return clk_prepare_enable(mtkd->clk);
}
#endif /* CONFIG_PM */
static const struct dev_pm_ops mtk_uart_apdma_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(mtk_uart_apdma_suspend, mtk_uart_apdma_resume)
SET_RUNTIME_PM_OPS(mtk_uart_apdma_runtime_suspend,
mtk_uart_apdma_runtime_resume, NULL)
};
static struct platform_driver mtk_uart_apdma_driver = {
.probe = mtk_uart_apdma_probe,
.remove = mtk_uart_apdma_remove,
.driver = {
.name = KBUILD_MODNAME,
.pm = &mtk_uart_apdma_pm_ops,
.of_match_table = of_match_ptr(mtk_uart_apdma_match),
},
};
module_platform_driver(mtk_uart_apdma_driver);
MODULE_DESCRIPTION("MediaTek UART APDMA Controller Driver");
MODULE_AUTHOR("Long Cheng <long.cheng@mediatek.com>");
MODULE_LICENSE("GPL v2");