Commit e5f4ae84 authored by Joachim Eastwood's avatar Joachim Eastwood Committed by Vinod Koul
Browse files

dmaengine: add driver for lpc18xx dmamux 



Add support for DMA on NXP LPC18xx/43xx platforms which has
a multiplexer in front of the PL080 dma request lines.

The mux is a single register in the LPC18xx/43xx CREG block
and can multiplex up to 4 request lines to each of the 16
lines on the PL080.

Signed-off-by: default avatarJoachim Eastwood <manabian@gmail.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent fbd7e410

drivers/dma/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -63,6 +63,15 @@ config AMBA_PL08X 
	  Platform has a PL08x DMAC device

	  which can provide DMA engine support



config LPC18XX_DMAMUX

	bool "NXP LPC18xx/43xx DMA MUX for PL080"

	depends on ARCH_LPC18XX || COMPILE_TEST

	depends on OF && AMBA_PL08X

	select MFD_SYSCON

	help

	  Enable support for DMA on NXP LPC18xx/43xx platforms

	  with PL080 and multiplexed DMA request lines.



config INTEL_IOATDMA

	tristate "Intel I/OAT DMA support"

	depends on PCI && X86

drivers/dma/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ obj-$(CONFIG_TI_EDMA) += edma.o 
obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o

obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o

obj-$(CONFIG_S3C24XX_DMAC) += s3c24xx-dma.o

obj-$(CONFIG_LPC18XX_DMAMUX) += lpc18xx-dmamux.o

obj-$(CONFIG_PL330_DMA) += pl330.o

obj-$(CONFIG_PCH_DMA) += pch_dma.o

obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o

drivers/dma/lpc18xx-dmamux.c

0 → 100644
+183 −0
Original line number Diff line number Diff line 
/*

 * 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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