diff options
Diffstat (limited to 'drivers/dma/ti-dma-crossbar.c')
| -rw-r--r-- | drivers/dma/ti-dma-crossbar.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/dma/ti-dma-crossbar.c b/drivers/dma/ti-dma-crossbar.c new file mode 100644 index 000000000..24f5ca235 --- /dev/null +++ b/drivers/dma/ti-dma-crossbar.c @@ -0,0 +1,188 @@ +/* + * 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); |