diff options
Diffstat (limited to 'kernel/drivers/dma/lpc18xx-dmamux.c')
| -rw-r--r-- | kernel/drivers/dma/lpc18xx-dmamux.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/kernel/drivers/dma/lpc18xx-dmamux.c b/kernel/drivers/dma/lpc18xx-dmamux.c new file mode 100644 index 000000000..761f32687 --- /dev/null +++ b/kernel/drivers/dma/lpc18xx-dmamux.c @@ -0,0 +1,183 @@ +/* + * 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); |