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/*
* DMA Router driver for LPC18xx/43xx DMA MUX
*
* Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
*
* Based on TI DMA Crossbar driver by:
* Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
* Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/err.h>
#include <linux/init.h>
#include <linux/mfd/syscon.h>
#include <linux/of_device.h>
#include <linux/of_dma.h>
#include <linux/regmap.h>
#include <linux/spinlock.h>
/* CREG register offset and macros for mux manipulation */
#define LPC18XX_CREG_DMAMUX 0x11c
#define LPC18XX_DMAMUX_VAL(v, n) ((v) << (n * 2))
#define LPC18XX_DMAMUX_MASK(n) (0x3 << (n * 2))
#define LPC18XX_DMAMUX_MAX_VAL 0x3
struct lpc18xx_dmamux {
u32 value;
bool busy;
};
struct lpc18xx_dmamux_data {
struct dma_router dmarouter;
struct lpc18xx_dmamux *muxes;
u32 dma_master_requests;
u32 dma_mux_requests;
struct regmap *reg;
spinlock_t lock;
};
static void lpc18xx_dmamux_free(struct device *dev, void *route_data)
{
struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev);
struct lpc18xx_dmamux *mux = route_data;
unsigned long flags;
spin_lock_irqsave(&dmamux->lock, flags);
mux->busy = false;
spin_unlock_irqrestore(&dmamux->lock, flags);
}
static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,
struct of_dma *ofdma)
{
struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev);
unsigned long flags;
unsigned mux;
if (dma_spec->args_count != 3) {
dev_err(&pdev->dev, "invalid number of dma mux args\n");
return ERR_PTR(-EINVAL);
}
mux = dma_spec->args[0];
if (mux >= dmamux->dma_master_requests) {
dev_err(&pdev->dev, "invalid mux number: %d\n",
dma_spec->args[0]);
return ERR_PTR(-EINVAL);
}
if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) {
dev_err(&pdev->dev, "invalid dma mux value: %d\n",
dma_spec->args[1]);
return ERR_PTR(-EINVAL);
}
/* The of_node_put() will be done in the core for the node */
dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
if (!dma_spec->np) {
dev_err(&pdev->dev, "can't get dma master\n");
return ERR_PTR(-EINVAL);
}
spin_lock_irqsave(&dmamux->lock, flags);
if (dmamux->muxes[mux].busy) {
spin_unlock_irqrestore(&dmamux->lock, flags);
dev_err(&pdev->dev, "dma request %u busy with %u.%u\n",
mux, mux, dmamux->muxes[mux].value);
of_node_put(dma_spec->np);
return ERR_PTR(-EBUSY);
}
dmamux->muxes[mux].busy = true;
dmamux->muxes[mux].value = dma_spec->args[1];
regmap_update_bits(dmamux->reg, LPC18XX_CREG_DMAMUX,
LPC18XX_DMAMUX_MASK(mux),
LPC18XX_DMAMUX_VAL(dmamux->muxes[mux].value, mux));
spin_unlock_irqrestore(&dmamux->lock, flags);
dma_spec->args[1] = dma_spec->args[2];
dma_spec->args_count = 2;
dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux,
dmamux->muxes[mux].value, mux);
return &dmamux->muxes[mux];
}
static int lpc18xx_dmamux_probe(struct platform_device *pdev)
{
struct device_node *dma_np, *np = pdev->dev.of_node;
struct lpc18xx_dmamux_data *dmamux;
int ret;
dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
if (!dmamux)
return -ENOMEM;
dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg");
if (IS_ERR(dmamux->reg)) {
dev_err(&pdev->dev, "syscon lookup failed\n");
return PTR_ERR(dmamux->reg);
}
ret = of_property_read_u32(np, "dma-requests",
&dmamux->dma_mux_requests);
if (ret) {
dev_err(&pdev->dev, "missing dma-requests property\n");
return ret;
}
dma_np = of_parse_phandle(np, "dma-masters", 0);
if (!dma_np) {
dev_err(&pdev->dev, "can't get dma master\n");
return -ENODEV;
}
ret = of_property_read_u32(dma_np, "dma-requests",
&dmamux->dma_master_requests);
of_node_put(dma_np);
if (ret) {
dev_err(&pdev->dev, "missing master dma-requests property\n");
return ret;
}
dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests,
sizeof(struct lpc18xx_dmamux),
GFP_KERNEL);
if (!dmamux->muxes)
return -ENOMEM;
spin_lock_init(&dmamux->lock);
platform_set_drvdata(pdev, dmamux);
dmamux->dmarouter.dev = &pdev->dev;
dmamux->dmarouter.route_free = lpc18xx_dmamux_free;
return of_dma_router_register(np, lpc18xx_dmamux_reserve,
&dmamux->dmarouter);
}
static const struct of_device_id lpc18xx_dmamux_match[] = {
{ .compatible = "nxp,lpc1850-dmamux" },
{},
};
static struct platform_driver lpc18xx_dmamux_driver = {
.probe = lpc18xx_dmamux_probe,
.driver = {
.name = "lpc18xx-dmamux",
.of_match_table = lpc18xx_dmamux_match,
},
};
static int __init lpc18xx_dmamux_init(void)
{
return platform_driver_register(&lpc18xx_dmamux_driver);
}
arch_initcall(lpc18xx_dmamux_init);
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