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Release 4.14 drivers/dma/lpc18xx-dmamux.c

Directory: drivers/dma
/*
 * 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); }

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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]; }

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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); }

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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); }

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arch_initcall(lpc18xx_dmamux_init);

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Directory: drivers/dma
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