// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) STMicroelectronics SA 2017
* Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com>
* Pierre-Yves Mordret <pierre-yves.mordret@st.com>
*
* DMA Router driver for STM32 DMA MUX
*
* Based on TI DMA Crossbar driver
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/of_dma.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#define STM32_DMAMUX_CCR(x) (0x4 * (x))
#define STM32_DMAMUX_MAX_DMA_REQUESTS 32
#define STM32_DMAMUX_MAX_REQUESTS 255
struct stm32_dmamux {
u32 master;
u32 request;
u32 chan_id;
};
struct stm32_dmamux_data {
struct dma_router dmarouter;
struct clk *clk;
struct reset_control *rst;
void __iomem *iomem;
u32 dma_requests; /* Number of DMA requests connected to DMAMUX */
u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */
spinlock_t lock; /* Protects register access */
unsigned long *dma_inuse; /* Used DMA channel */
u32 dma_reqs[]; /* Number of DMA Request per DMA masters.
* [0] holds number of DMA Masters.
* To be kept at very end end of this structure
*/
};
static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
{
return readl_relaxed(iomem + reg);
}
static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
{
writel_relaxed(val, iomem + reg);
}
static void stm32_dmamux_free(struct device *dev, void *route_data)
{
struct stm32_dmamux_data *dmamux = dev_get_drvdata(dev);
struct stm32_dmamux *mux = route_data;
unsigned long flags;
/* Clear dma request */
spin_lock_irqsave(&dmamux->lock, flags);
stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0);
clear_bit(mux->chan_id, dmamux->dma_inuse);
pm_runtime_put_sync(dev);
spin_unlock_irqrestore(&dmamux->lock, flags);
dev_dbg(dev, "Unmapping DMAMUX(%u) to DMA%u(%u)\n",
mux->request, mux->master, mux->chan_id);
kfree(mux);
}
static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma)
{
struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
struct stm32_dmamux_data *dmamux = platform_get_drvdata(pdev);
struct stm32_dmamux *mux;
u32 i, min, max;
int ret;
unsigned long flags;
if (dma_spec->args_count != 3) {
dev_err(&pdev->dev, "invalid number of dma mux args\n");
return ERR_PTR(-EINVAL);
}
if (dma_spec->args[0] > dmamux->dmamux_requests) {
dev_err(&pdev->dev, "invalid mux request number: %d\n",
dma_spec->args[0]);
return ERR_PTR(-EINVAL);
}
mux = kzalloc(sizeof(*mux), GFP_KERNEL);
if (!mux)
return ERR_PTR(-ENOMEM);
spin_lock_irqsave(&dmamux->lock, flags);
mux->chan_id = find_first_zero_bit(dmamux->dma_inuse,
dmamux->dma_requests);
if (mux->chan_id == dmamux->dma_requests) {
spin_unlock_irqrestore(&dmamux->lock, flags);
dev_err(&pdev->dev, "Run out of free DMA requests\n");
ret = -ENOMEM;
goto error_chan_id;
}
set_bit(mux->chan_id, dmamux->dma_inuse);
spin_unlock_irqrestore(&dmamux->lock, flags);
/* Look for DMA Master */
for (i = 1, min = 0, max = dmamux->dma_reqs[i];
i <= dmamux->dma_reqs[0];
min += dmamux->dma_reqs[i], max += dmamux->dma_reqs[++i])
if (mux->chan_id < max)
break;
mux->master = i - 1;
/* The of_node_put() will be done in of_dma_router_xlate function */
dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1);
if (!dma_spec->np) {
dev_err(&pdev->dev, "can't get dma master\n");
ret = -EINVAL;
goto error;
}
/* Set dma request */
spin_lock_irqsave(&dmamux->lock, flags);
ret = pm_runtime_get_sync(&pdev->dev);
if (ret < 0) {
spin_unlock_irqrestore(&dmamux->lock, flags);
goto error;
}
spin_unlock_irqrestore(&dmamux->lock, flags);
mux->request = dma_spec->args[0];
/* craft DMA spec */
dma_spec->args[3] = dma_spec->args[2];
dma_spec->args[2] = dma_spec->args[1];
dma_spec->args[1] = 0;
dma_spec->args[0] = mux->chan_id - min;
dma_spec->args_count = 4;
stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id),
mux->request);
dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n",
mux->request, mux->master, mux->chan_id);
return mux;
error:
clear_bit(mux->chan_id, dmamux->dma_inuse);
error_chan_id:
kfree(mux);
return ERR_PTR(ret);
}
static const struct of_device_id stm32_stm32dma_master_match[] = {
{ .compatible = "st,stm32-dma", },
{},
};
static int stm32_dmamux_probe(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
const struct of_device_id *match;
struct device_node *dma_node;
struct stm32_dmamux_data *stm32_dmamux;
struct resource *res;
void __iomem *iomem;
int i, count, ret;
u32 dma_req;
if (!node)
return -ENODEV;
count = device_property_count_u32(&pdev->dev, "dma-masters");
if (count < 0) {
dev_err(&pdev->dev, "Can't get DMA master(s) node\n");
return -ENODEV;
}
stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) +
sizeof(u32) * (count + 1), GFP_KERNEL);
if (!stm32_dmamux)
return -ENOMEM;
dma_req = 0;
for (i = 1; i <= count; i++) {
dma_node = of_parse_phandle(node, "dma-masters", i - 1);
match = of_match_node(stm32_stm32dma_master_match, dma_node);
if (!match) {
dev_err(&pdev->dev, "DMA master is not supported\n");
of_node_put(dma_node);
return -EINVAL;
}
if (of_property_read_u32(dma_node, "dma-requests",
&stm32_dmamux->dma_reqs[i])) {
dev_info(&pdev->dev,
"Missing MUX output information, using %u.\n",
STM32_DMAMUX_MAX_DMA_REQUESTS);
stm32_dmamux->dma_reqs[i] =
STM32_DMAMUX_MAX_DMA_REQUESTS;
}
dma_req += stm32_dmamux->dma_reqs[i];
of_node_put(dma_node);
}
if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) {
dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n");
return -ENODEV;
}
stm32_dmamux->dma_requests = dma_req;
stm32_dmamux->dma_reqs[0] = count;
stm32_dmamux->dma_inuse = devm_kcalloc(&pdev->dev,
BITS_TO_LONGS(dma_req),
sizeof(unsigned long),
GFP_KERNEL);
if (!stm32_dmamux->dma_inuse)
return -ENOMEM;
if (device_property_read_u32(&pdev->dev, "dma-requests",
&stm32_dmamux->dmamux_requests)) {
stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
stm32_dmamux->dmamux_requests);
}
pm_runtime_get_noresume(&pdev->dev);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
iomem = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(iomem))
return PTR_ERR(iomem);
spin_lock_init(&stm32_dmamux->lock);
stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(stm32_dmamux->clk)) {
ret = PTR_ERR(stm32_dmamux->clk);
if (ret == -EPROBE_DEFER)
dev_info(&pdev->dev, "Missing controller clock\n");
return ret;
}
stm32_dmamux->rst = devm_reset_control_get(&pdev->dev, NULL);
if (!IS_ERR(stm32_dmamux->rst)) {
reset_control_assert(stm32_dmamux->rst);
udelay(2);
reset_control_deassert(stm32_dmamux->rst);
}
stm32_dmamux->iomem = iomem;
stm32_dmamux->dmarouter.dev = &pdev->dev;
stm32_dmamux->dmarouter.route_free = stm32_dmamux_free;
platform_set_drvdata(pdev, stm32_dmamux);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
if (!IS_ERR(stm32_dmamux->clk)) {
ret = clk_prepare_enable(stm32_dmamux->clk);
if (ret < 0) {
dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
return ret;
}
}
pm_runtime_get_noresume(&pdev->dev);
/* Reset the dmamux */
for (i = 0; i < stm32_dmamux->dma_requests; i++)
stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0);
pm_runtime_put(&pdev->dev);
return of_dma_router_register(node, stm32_dmamux_route_allocate,
&stm32_dmamux->dmarouter);
}
#ifdef [31mCONFIG_PM[0m
static int stm32_dmamux_runtime_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
clk_disable_unprepare(stm32_dmamux->clk);
return 0;
}
static int stm32_dmamux_runtime_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
int ret;
ret = clk_prepare_enable(stm32_dmamux->clk);
if (ret) {
dev_err(&pdev->dev, "failed to prepare_enable clock\n");
return ret;
}
return 0;
}
#endif
static const struct dev_pm_ops stm32_dmamux_pm_ops = {
SET_RUNTIME_PM_OPS(stm32_dmamux_runtime_suspend,
stm32_dmamux_runtime_resume, NULL)
};
static const struct of_device_id stm32_dmamux_match[] = {
{ .compatible = "st,stm32h7-dmamux" },
{},
};
static struct platform_driver stm32_dmamux_driver = {
.probe = stm32_dmamux_probe,
.driver = {
.name = "stm32-dmamux",
.of_match_table = stm32_dmamux_match,
.pm = &stm32_dmamux_pm_ops,
},
};
static int __init stm32_dmamux_init(void)
{
return platform_driver_register(&stm32_dmamux_driver);
}
arch_initcall(stm32_dmamux_init);
MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
MODULE_LICENSE("GPL v2");