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![Joachim Eastwood](/assets/img/avatar_default.png)
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: Joachim Eastwood <manabian@gmail.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
183 lines
4.9 KiB
C
183 lines
4.9 KiB
C
/*
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* DMA Router driver for LPC18xx/43xx DMA MUX
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*
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* Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
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*
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* Based on TI DMA Crossbar driver by:
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* Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
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* Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/mfd/syscon.h>
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#include <linux/of_device.h>
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#include <linux/of_dma.h>
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#include <linux/regmap.h>
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#include <linux/spinlock.h>
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/* CREG register offset and macros for mux manipulation */
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#define LPC18XX_CREG_DMAMUX 0x11c
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#define LPC18XX_DMAMUX_VAL(v, n) ((v) << (n * 2))
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#define LPC18XX_DMAMUX_MASK(n) (0x3 << (n * 2))
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#define LPC18XX_DMAMUX_MAX_VAL 0x3
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struct lpc18xx_dmamux {
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u32 value;
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bool busy;
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};
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struct lpc18xx_dmamux_data {
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struct dma_router dmarouter;
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struct lpc18xx_dmamux *muxes;
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u32 dma_master_requests;
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u32 dma_mux_requests;
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struct regmap *reg;
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spinlock_t lock;
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};
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static void lpc18xx_dmamux_free(struct device *dev, void *route_data)
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{
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struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev);
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struct lpc18xx_dmamux *mux = route_data;
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unsigned long flags;
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spin_lock_irqsave(&dmamux->lock, flags);
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mux->busy = false;
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spin_unlock_irqrestore(&dmamux->lock, flags);
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}
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static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,
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struct of_dma *ofdma)
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{
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struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
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struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev);
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unsigned long flags;
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unsigned mux;
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if (dma_spec->args_count != 3) {
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dev_err(&pdev->dev, "invalid number of dma mux args\n");
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return ERR_PTR(-EINVAL);
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}
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mux = dma_spec->args[0];
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if (mux >= dmamux->dma_master_requests) {
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dev_err(&pdev->dev, "invalid mux number: %d\n",
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dma_spec->args[0]);
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return ERR_PTR(-EINVAL);
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}
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if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) {
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dev_err(&pdev->dev, "invalid dma mux value: %d\n",
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dma_spec->args[1]);
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return ERR_PTR(-EINVAL);
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}
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/* The of_node_put() will be done in the core for the node */
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dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
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if (!dma_spec->np) {
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dev_err(&pdev->dev, "can't get dma master\n");
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return ERR_PTR(-EINVAL);
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}
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spin_lock_irqsave(&dmamux->lock, flags);
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if (dmamux->muxes[mux].busy) {
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spin_unlock_irqrestore(&dmamux->lock, flags);
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dev_err(&pdev->dev, "dma request %u busy with %u.%u\n",
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mux, mux, dmamux->muxes[mux].value);
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of_node_put(dma_spec->np);
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return ERR_PTR(-EBUSY);
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}
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dmamux->muxes[mux].busy = true;
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dmamux->muxes[mux].value = dma_spec->args[1];
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regmap_update_bits(dmamux->reg, LPC18XX_CREG_DMAMUX,
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LPC18XX_DMAMUX_MASK(mux),
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LPC18XX_DMAMUX_VAL(dmamux->muxes[mux].value, mux));
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spin_unlock_irqrestore(&dmamux->lock, flags);
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dma_spec->args[1] = dma_spec->args[2];
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dma_spec->args_count = 2;
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dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux,
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dmamux->muxes[mux].value, mux);
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return &dmamux->muxes[mux];
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}
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static int lpc18xx_dmamux_probe(struct platform_device *pdev)
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{
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struct device_node *dma_np, *np = pdev->dev.of_node;
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struct lpc18xx_dmamux_data *dmamux;
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int ret;
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dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
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if (!dmamux)
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return -ENOMEM;
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dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg");
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if (IS_ERR(dmamux->reg)) {
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dev_err(&pdev->dev, "syscon lookup failed\n");
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return PTR_ERR(dmamux->reg);
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}
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ret = of_property_read_u32(np, "dma-requests",
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&dmamux->dma_mux_requests);
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if (ret) {
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dev_err(&pdev->dev, "missing dma-requests property\n");
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return ret;
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}
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dma_np = of_parse_phandle(np, "dma-masters", 0);
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if (!dma_np) {
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dev_err(&pdev->dev, "can't get dma master\n");
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return -ENODEV;
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}
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ret = of_property_read_u32(dma_np, "dma-requests",
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&dmamux->dma_master_requests);
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of_node_put(dma_np);
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if (ret) {
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dev_err(&pdev->dev, "missing master dma-requests property\n");
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return ret;
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}
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dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests,
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sizeof(struct lpc18xx_dmamux),
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GFP_KERNEL);
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if (!dmamux->muxes)
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return -ENOMEM;
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spin_lock_init(&dmamux->lock);
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platform_set_drvdata(pdev, dmamux);
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dmamux->dmarouter.dev = &pdev->dev;
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dmamux->dmarouter.route_free = lpc18xx_dmamux_free;
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return of_dma_router_register(np, lpc18xx_dmamux_reserve,
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&dmamux->dmarouter);
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}
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static const struct of_device_id lpc18xx_dmamux_match[] = {
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{ .compatible = "nxp,lpc1850-dmamux" },
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{},
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};
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static struct platform_driver lpc18xx_dmamux_driver = {
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.probe = lpc18xx_dmamux_probe,
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.driver = {
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.name = "lpc18xx-dmamux",
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.of_match_table = lpc18xx_dmamux_match,
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},
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};
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static int __init lpc18xx_dmamux_init(void)
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{
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return platform_driver_register(&lpc18xx_dmamux_driver);
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}
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arch_initcall(lpc18xx_dmamux_init);
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