drivers/dma/ti-dma-crossbar.c

/*
 *  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/slab.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/idr.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_dma.h>

#define TI_XBAR_OUTPUTS	127
#define TI_XBAR_INPUTS	256

static DEFINE_IDR(map_idr);

struct ti_dma_xbar_data {
	void __iomem *iomem;

	struct dma_router dmarouter;

	u16 safe_val; /* Value to rest the crossbar lines */
	u32 xbar_requests; /* number of DMA requests connected to XBAR */
	u32 dma_requests; /* number of DMA requests forwarded to DMA */
};

struct ti_dma_xbar_map {
	u16 xbar_in;
	int xbar_out;
};

static inline void ti_dma_xbar_write(void __iomem *iomem, int xbar, u16 val)
{
	writew_relaxed(val, iomem + (xbar * 2));
}

static void ti_dma_xbar_free(struct device *dev, void *route_data)
{
	struct ti_dma_xbar_data *xbar = dev_get_drvdata(dev);
	struct ti_dma_xbar_map *map = route_data;

	dev_dbg(dev, "Unmapping XBAR%u (was routed to %d)\n",
		map->xbar_in, map->xbar_out);

	ti_dma_xbar_write(xbar->iomem, map->xbar_out, xbar->safe_val);
	idr_remove(&map_idr, map->xbar_out);
	kfree(map);
}

static void *ti_dma_xbar_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 ti_dma_xbar_data *xbar = platform_get_drvdata(pdev);
	struct ti_dma_xbar_map *map;

	if (dma_spec->args[0] >= xbar->xbar_requests) {
		dev_err(&pdev->dev, "Invalid XBAR request number: %d\n",
			dma_spec->args[0]);
		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);
	}

	map = kzalloc(sizeof(*map), GFP_KERNEL);
	if (!map) {
		of_node_put(dma_spec->np);
		return ERR_PTR(-ENOMEM);
	}

	map->xbar_out = idr_alloc(&map_idr, NULL, 0, xbar->dma_requests,
				  GFP_KERNEL);
	map->xbar_in = (u16)dma_spec->args[0];

	/* The DMA request is 1 based in sDMA */
	dma_spec->args[0] = map->xbar_out + 1;

	dev_dbg(&pdev->dev, "Mapping XBAR%u to DMA%d\n",
		map->xbar_in, map->xbar_out);

	ti_dma_xbar_write(xbar->iomem, map->xbar_out, map->xbar_in);

	return map;
}

static int ti_dma_xbar_probe(struct platform_device *pdev)
{
	struct device_node *node = pdev->dev.of_node;
	struct device_node *dma_node;
	struct ti_dma_xbar_data *xbar;
	struct resource *res;
	u32 safe_val;
	void __iomem *iomem;
	int i, ret;

	if (!node)
		return -ENODEV;

	xbar = devm_kzalloc(&pdev->dev, sizeof(*xbar), GFP_KERNEL);
	if (!xbar)
		return -ENOMEM;

	dma_node = of_parse_phandle(node, "dma-masters", 0);
	if (!dma_node) {
		dev_err(&pdev->dev, "Can't get DMA master node\n");
		return -ENODEV;
	}

	if (of_property_read_u32(dma_node, "dma-requests",
				 &xbar->dma_requests)) {
		dev_info(&pdev->dev,
			 "Missing XBAR output information, using %u.\n",
			 TI_XBAR_OUTPUTS);
		xbar->dma_requests = TI_XBAR_OUTPUTS;
	}
	of_node_put(dma_node);

	if (of_property_read_u32(node, "dma-requests", &xbar->xbar_requests)) {
		dev_info(&pdev->dev,
			 "Missing XBAR input information, using %u.\n",
			 TI_XBAR_INPUTS);
		xbar->xbar_requests = TI_XBAR_INPUTS;
	}

	if (!of_property_read_u32(node, "ti,dma-safe-map", &safe_val))
		xbar->safe_val = (u16)safe_val;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENODEV;

	iomem = devm_ioremap_resource(&pdev->dev, res);
	if (!iomem)
		return -ENOMEM;

	xbar->iomem = iomem;

	xbar->dmarouter.dev = &pdev->dev;
	xbar->dmarouter.route_free = ti_dma_xbar_free;

	platform_set_drvdata(pdev, xbar);

	/* Reset the crossbar */
	for (i = 0; i < xbar->dma_requests; i++)
		ti_dma_xbar_write(xbar->iomem, i, xbar->safe_val);

	ret = of_dma_router_register(node, ti_dma_xbar_route_allocate,
				     &xbar->dmarouter);
	if (ret) {
		/* Restore the defaults for the crossbar */
		for (i = 0; i < xbar->dma_requests; i++)
			ti_dma_xbar_write(xbar->iomem, i, i);
	}

	return ret;
}

static const struct of_device_id ti_dma_xbar_match[] = {
	{ .compatible = "ti,dra7-dma-crossbar" },
	{},
};

static struct platform_driver ti_dma_xbar_driver = {
	.driver = {
		.name = "ti-dma-crossbar",
		.of_match_table = of_match_ptr(ti_dma_xbar_match),
	},
	.probe	= ti_dma_xbar_probe,
};

int omap_dmaxbar_init(void)
{
	return platform_driver_register(&ti_dma_xbar_driver);
}
arch_initcall(omap_dmaxbar_init);