linux/drivers/dma/stm32-dmamux.c
Etienne Carriere 6cc7089764 dmaengine: stm32-dmamux: driver defers probe for clock and reset
Changes STM32 DMAMUX driver to defer its probe operation when
reset controller is expected but has not been probed yet.

Changes error traces when failing to get a system resource so that
it is not printed on failure with deferred probing.

Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Link: https://lore.kernel.org/r/20200128094158.20361-5-amelie.delaunay@st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-02-24 22:22:44 +05:30

411 lines
10 KiB
C

// 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;
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 ccr[STM32_DMAMUX_MAX_DMA_REQUESTS]; /* Used to backup CCR register
* in suspend
*/
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;
struct reset_control *rst;
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_err(&pdev->dev, "Missing clock controller\n");
return ret;
}
ret = clk_prepare_enable(stm32_dmamux->clk);
if (ret < 0) {
dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
return ret;
}
rst = devm_reset_control_get(&pdev->dev, NULL);
if (IS_ERR(rst)) {
ret = PTR_ERR(rst);
if (ret == -EPROBE_DEFER)
goto err_clk;
} else {
reset_control_assert(rst);
udelay(2);
reset_control_deassert(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);
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);
ret = of_dma_router_register(node, stm32_dmamux_route_allocate,
&stm32_dmamux->dmarouter);
if (ret)
goto err_clk;
return 0;
err_clk:
clk_disable_unprepare(stm32_dmamux->clk);
return ret;
}
#ifdef CONFIG_PM
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
#ifdef CONFIG_PM_SLEEP
static int stm32_dmamux_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
int i, ret;
ret = pm_runtime_get_sync(dev);
if (ret < 0)
return ret;
for (i = 0; i < stm32_dmamux->dma_requests; i++)
stm32_dmamux->ccr[i] = stm32_dmamux_read(stm32_dmamux->iomem,
STM32_DMAMUX_CCR(i));
pm_runtime_put_sync(dev);
pm_runtime_force_suspend(dev);
return 0;
}
static int stm32_dmamux_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
int i, ret;
ret = pm_runtime_force_resume(dev);
if (ret < 0)
return ret;
ret = pm_runtime_get_sync(dev);
if (ret < 0)
return ret;
for (i = 0; i < stm32_dmamux->dma_requests; i++)
stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i),
stm32_dmamux->ccr[i]);
pm_runtime_put_sync(dev);
return 0;
}
#endif
static const struct dev_pm_ops stm32_dmamux_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(stm32_dmamux_suspend, stm32_dmamux_resume)
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");