[PATCH RFC 3/4] dmaengine: add driver for lpc18xx dmamux
Joachim Eastwood
manabian at gmail.com
Sun Jun 14 04:22:16 PDT 2015
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 at gmail.com>
---
drivers/dma/Kconfig | 9 +++
drivers/dma/Makefile | 1 +
drivers/dma/lpc18xx-dmamux.c | 184 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 194 insertions(+)
create mode 100644 drivers/dma/lpc18xx-dmamux.c
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index dfe72a0f46dc..e119dd19e9b4 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -76,6 +76,15 @@ 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
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index bc12f9a4e62b..44ef3ef29ebe 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -31,6 +31,7 @@ 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
diff --git a/drivers/dma/lpc18xx-dmamux.c b/drivers/dma/lpc18xx-dmamux.c
new file mode 100644
index 000000000000..26ba76c13be2
--- /dev/null
+++ b/drivers/dma/lpc18xx-dmamux.c
@@ -0,0 +1,184 @@
+/*
+ * DMA Router driver for LPC18xx/43xx DMA MUX
+ *
+ * Copyright (C) 2015 Joachim Eastwood <manabian at gmail.com>
+ *
+ * Based on TI DMA Crossbar driver by:
+ * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
+ * Author: Peter Ujfalusi <peter.ujfalusi at 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/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_address.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_info(&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);
--
1.8.0
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