[Patch v4 06/10] dmaengine: Add dma router for pl08x in LPC32XX SoC

Piotr Wojtaszczyk
2024-06-20T17:59:40Z

LPC32XX connects few of its peripherals to pl08x DMA thru a multiplexer,
this driver allows to route a signal request line thru the multiplexer for
given peripheral.

Signed-off-by: Piotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
---
Changes for v4:
- This patch is new in v4

MAINTAINERS | 1 +
drivers/dma/Kconfig | 9 ++
drivers/dma/Makefile | 1 +
drivers/dma/lpc32xx-dmamux.c | 195 +++++++++++++++++++++++++++++++++++
4 files changed, 206 insertions(+)
create mode 100644 drivers/dma/lpc32xx-dmamux.c

diff --git a/MAINTAINERS b/MAINTAINERS
index fadf1baafd89..5ffe988ee282 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2403,6 +2403,7 @@ R: Vladimir Zapolskiy <vz@mleia.com>
L: linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
S: Maintained
F: Documentation/devicetree/bindings/dma/nxp,lpc3220-dmamux.yaml
+F: drivers/dma/lpc32xx-dmamux.c
N: lpc32xx

ARM/Marvell Dove/MV78xx0/Orion SOC support
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 002a5ec80620..aeace3d7e066 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -378,6 +378,15 @@ config LPC18XX_DMAMUX
Enable support for DMA on NXP LPC18xx/43xx platforms
with PL080 and multiplexed DMA request lines.

+config LPC32XX_DMAMUX
+ bool "NXP LPC32xx DMA MUX for PL080"
+ depends on ARCH_LPC32XX || COMPILE_TEST
+ depends on OF && AMBA_PL08X
+ select MFD_SYSCON
+ help
+ Support for PL080 multiplexed DMA request lines on
+ LPC32XX platrofm.
+
config LS2X_APB_DMA
tristate "Loongson LS2X APB DMA support"
depends on LOONGARCH || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 802ca916f05f..6f1350b62e7f 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -50,6 +50,7 @@ obj-$(CONFIG_INTEL_IOATDMA) += ioat/
obj-y += idxd/
obj-$(CONFIG_K3_DMA) += k3dma.o
obj-$(CONFIG_LPC18XX_DMAMUX) += lpc18xx-dmamux.o
+obj-$(CONFIG_LPC32XX_DMAMUX) += lpc32xx-dmamux.o
obj-$(CONFIG_LS2X_APB_DMA) += ls2x-apb-dma.o
obj-$(CONFIG_MILBEAUT_HDMAC) += milbeaut-hdmac.o
obj-$(CONFIG_MILBEAUT_XDMAC) += milbeaut-xdmac.o
diff --git a/drivers/dma/lpc32xx-dmamux.c b/drivers/dma/lpc32xx-dmamux.c
new file mode 100644
index 000000000000..4e6ce6026164
--- /dev/null
+++ b/drivers/dma/lpc32xx-dmamux.c
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright 2024 Timesys Corporation <piotr.wojtaszczyk@timesys.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>
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+
+#define LPC32XX_SSP_CLK_CTRL 0x78
+#define LPC32XX_I2S_CLK_CTRL 0x7c
+
+struct lpc32xx_dmamux {
+ int signal;
+ char *name_sel0;
+ char *name_sel1;
+ int muxval;
+ int muxreg;
+ int bit;
+ bool busy;
+};
+
+/* From LPC32x0 User manual "3.2.1 DMA request signals" */
+static struct lpc32xx_dmamux lpc32xx_muxes[] = {
+ {
+ .signal = 3,
+ .name_sel0 = "spi2-rx-tx",
+ .name_sel1 = "ssp1-rx",
+ .muxreg = LPC32XX_SSP_CLK_CTRL,
+ .bit = 5,
+ },
+ {
+ .signal = 10,
+ .name_sel0 = "uart7-rx",
+ .name_sel1 = "i2s1-dma1",
+ .muxreg = LPC32XX_I2S_CLK_CTRL,
+ .bit = 4,
+ },
+ {
+ .signal = 11,
+ .name_sel0 = "spi1-rx-tx",
+ .name_sel1 = "ssp1-tx",
+ .muxreg = LPC32XX_SSP_CLK_CTRL,
+ .bit = 4,
+ },
+ {
+ .signal = 14,
+ .name_sel0 = "none",
+ .name_sel1 = "ssp0-rx",
+ .muxreg = LPC32XX_SSP_CLK_CTRL,
+ .bit = 3,
+ },
+ {
+ .signal = 15,
+ .name_sel0 = "none",
+ .name_sel1 = "ssp0-tx",
+ .muxreg = LPC32XX_SSP_CLK_CTRL,
+ .bit = 2,
+ },
+};
+
+struct lpc32xx_dmamux_data {
+ struct dma_router dmarouter;
+ struct regmap *reg;
+ spinlock_t lock; /* protects busy status flag */
+};
+
+static void lpc32xx_dmamux_release(struct device *dev, void *route_data)
+{
+ struct lpc32xx_dmamux_data *dmamux = dev_get_drvdata(dev);
+ struct lpc32xx_dmamux *mux = route_data;
+ unsigned long flags;
+
+ dev_dbg(dev, "releasing dma request signal %d routed to %s\n",
+ mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
+
+ guard(spinlock)(&dmamux->lock);
+
+ mux->busy = false;
+}
+
+static void *lpc32xx_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 device *dev = &pdev->dev;
+ struct lpc32xx_dmamux_data *dmamux = platform_get_drvdata(pdev);
+ unsigned long flags;
+ struct lpc32xx_dmamux *mux = NULL;
+ int i;
+
+ if (dma_spec->args_count != 3) {
+ dev_err(&pdev->dev, "invalid number of dma mux args\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(lpc32xx_muxes); i++) {
+ if (lpc32xx_muxes[i].signal == dma_spec->args[0])
+ mux = &lpc32xx_muxes[i];
+ }
+ if (!mux) {
+ dev_err(&pdev->dev, "invalid mux request number: %d\n",
+ dma_spec->args[0]);
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (dma_spec->args[2] > 1) {
+ 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 (mux->busy) {
+ spin_unlock_irqrestore(&dmamux->lock, flags);
+ dev_err(dev, "dma request signal %d busy, routed to %s\n",
+ mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
+ of_node_put(dma_spec->np);
+ return ERR_PTR(-EBUSY);
+ }
+
+ mux->busy = true;
+ mux->muxval = dma_spec->args[2] ? BIT(mux->bit) : 0;
+
+ regmap_update_bits(dmamux->reg, mux->muxreg, BIT(mux->bit), mux->muxval);
+ spin_unlock_irqrestore(&dmamux->lock, flags);
+
+ dma_spec->args[2] = 0;
+ dma_spec->args_count = 2;
+
+ dev_dbg(dev, "dma request signal %d routed to %s\n",
+ mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
+
+ return mux;
+}
+
+static int lpc32xx_dmamux_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct lpc32xx_dmamux_data *dmamux;
+ int ret;
+
+ dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
+ if (!dmamux)
+ return -ENOMEM;
+
+ dmamux->reg = syscon_node_to_regmap(np->parent);
+ if (IS_ERR(dmamux->reg)) {
+ dev_err(&pdev->dev, "syscon lookup failed\n");
+ return PTR_ERR(dmamux->reg);
+ }
+
+ spin_lock_init(&dmamux->lock);
+ platform_set_drvdata(pdev, dmamux);
+ dmamux->dmarouter.dev = &pdev->dev;
+ dmamux->dmarouter.route_free = lpc32xx_dmamux_release;
+
+ return of_dma_router_register(np, lpc32xx_dmamux_reserve,
+ &dmamux->dmarouter);
+}
+
+static const struct of_device_id lpc32xx_dmamux_match[] = {
+ { .compatible = "nxp,lpc3220-dmamux" },
+ {},
+};
+
+static struct platform_driver lpc32xx_dmamux_driver = {
+ .probe = lpc32xx_dmamux_probe,
+ .driver = {
+ .name = "lpc32xx-dmamux",
+ .of_match_table = lpc32xx_dmamux_match,
+ },
+};
+
+static int __init lpc32xx_dmamux_init(void)
+{
+ return platform_driver_register(&lpc32xx_dmamux_driver);
+}
+arch_initcall(lpc32xx_dmamux_init);
--
2.25.1