dmaengine: dw: dmamux: Introduce RZN1 DMA router support

The Renesas RZN1 DMA IP is based on a DW core, with eg. an additional
dmamux register located in the system control area which can take up to
32 requests (16 per DMA controller). Each DMA channel can be wired to
two different peripherals.

We need two additional information from the 'dmas' property: the channel
(bit in the dmamux register) that must be accessed and the value of the
mux for this channel.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220427095653.91804-6-miquel.raynal@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/dw/Kconfig b/drivers/dma/dw/Kconfig
index db25f9b..a9828dd 100644 (file)
--- a/drivers/dma/dw/Kconfig
+++ b/drivers/dma/dw/Kconfig
@@ -16,6 +16,15 @@ config DW_DMAC
          Support the Synopsys DesignWare AHB DMA controller. This
          can be integrated in chips such as the Intel Cherrytrail.
 
+config RZN1_DMAMUX
+       tristate "Renesas RZ/N1 DMAMUX driver"
+       depends on DW_DMAC
+       depends on ARCH_RZN1 || COMPILE_TEST
+       help
+         Support the Renesas RZ/N1 DMAMUX which is located in front of
+         the Synopsys DesignWare AHB DMA controller located on Renesas
+         SoCs.
+
 config DW_DMAC_PCI
        tristate "Synopsys DesignWare AHB DMA PCI driver"
        depends on PCI

diff --git a/drivers/dma/dw/Makefile b/drivers/dma/dw/Makefile
index a6f358a..e179601 100644 (file)
--- a/drivers/dma/dw/Makefile
+++ b/drivers/dma/dw/Makefile
@@ -9,3 +9,5 @@ dw_dmac-$(CONFIG_OF)            += of.o
 
 obj-$(CONFIG_DW_DMAC_PCI)      += dw_dmac_pci.o
 dw_dmac_pci-y                  := pci.o
+
+obj-$(CONFIG_RZN1_DMAMUX)      += rzn1-dmamux.o

diff --git a/drivers/dma/dw/rzn1-dmamux.c b/drivers/dma/dw/rzn1-dmamux.c
new file mode 100644 (file)
index 0000000..11d254e
--- /dev/null
+++ b/drivers/dma/dw/rzn1-dmamux.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Schneider-Electric
+ * Author: Miquel Raynal <miquel.raynal@bootlin.com
+ * Based on TI crossbar driver written by Peter Ujfalusi <peter.ujfalusi@ti.com>
+ */
+#include <linux/bitops.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/slab.h>
+#include <linux/soc/renesas/r9a06g032-sysctrl.h>
+#include <linux/types.h>
+
+#define RNZ1_DMAMUX_NCELLS 6
+#define RZN1_DMAMUX_MAX_LINES 64
+#define RZN1_DMAMUX_LINES_PER_CTLR 16
+
+struct rzn1_dmamux_data {
+       struct dma_router dmarouter;
+       DECLARE_BITMAP(used_chans, 2 * RZN1_DMAMUX_LINES_PER_CTLR);
+};
+
+struct rzn1_dmamux_map {
+       unsigned int req_idx;
+};
+
+static void rzn1_dmamux_free(struct device *dev, void *route_data)
+{
+       struct rzn1_dmamux_data *dmamux = dev_get_drvdata(dev);
+       struct rzn1_dmamux_map *map = route_data;
+
+       dev_dbg(dev, "Unmapping DMAMUX request %u\n", map->req_idx);
+
+       clear_bit(map->req_idx, dmamux->used_chans);
+
+       kfree(map);
+}
+
+static void *rzn1_dmamux_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 rzn1_dmamux_data *dmamux = platform_get_drvdata(pdev);
+       struct rzn1_dmamux_map *map;
+       unsigned int dmac_idx, chan, val;
+       u32 mask;
+       int ret;
+
+       if (dma_spec->args_count != RNZ1_DMAMUX_NCELLS)
+               return ERR_PTR(-EINVAL);
+
+       map = kzalloc(sizeof(*map), GFP_KERNEL);
+       if (!map)
+               return ERR_PTR(-ENOMEM);
+
+       chan = dma_spec->args[0];
+       map->req_idx = dma_spec->args[4];
+       val = dma_spec->args[5];
+       dma_spec->args_count -= 2;
+
+       if (chan >= RZN1_DMAMUX_LINES_PER_CTLR) {
+               dev_err(&pdev->dev, "Invalid DMA request line: %u\n", chan);
+               ret = -EINVAL;
+               goto free_map;
+       }
+
+       if (map->req_idx >= RZN1_DMAMUX_MAX_LINES ||
+           (map->req_idx % RZN1_DMAMUX_LINES_PER_CTLR) != chan) {
+               dev_err(&pdev->dev, "Invalid MUX request line: %u\n", map->req_idx);
+               ret = -EINVAL;
+               goto free_map;
+       }
+
+       dmac_idx = map->req_idx >= RZN1_DMAMUX_LINES_PER_CTLR ? 1 : 0;
+       dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", dmac_idx);
+       if (!dma_spec->np) {
+               dev_err(&pdev->dev, "Can't get DMA master\n");
+               ret = -EINVAL;
+               goto free_map;
+       }
+
+       dev_dbg(&pdev->dev, "Mapping DMAMUX request %u to DMAC%u request %u\n",
+               map->req_idx, dmac_idx, chan);
+
+       if (test_and_set_bit(map->req_idx, dmamux->used_chans)) {
+               ret = -EBUSY;
+               goto free_map;
+       }
+
+       mask = BIT(map->req_idx);
+       ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
+       if (ret)
+               goto clear_bitmap;
+
+       return map;
+
+clear_bitmap:
+       clear_bit(map->req_idx, dmamux->used_chans);
+free_map:
+       kfree(map);
+
+       return ERR_PTR(ret);
+}
+
+static const struct of_device_id rzn1_dmac_match[] = {
+       { .compatible = "renesas,rzn1-dma" },
+       {}
+};
+
+static int rzn1_dmamux_probe(struct platform_device *pdev)
+{
+       struct device_node *mux_node = pdev->dev.of_node;
+       const struct of_device_id *match;
+       struct device_node *dmac_node;
+       struct rzn1_dmamux_data *dmamux;
+
+       dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
+       if (!dmamux)
+               return -ENOMEM;
+
+       dmac_node = of_parse_phandle(mux_node, "dma-masters", 0);
+       if (!dmac_node)
+               return dev_err_probe(&pdev->dev, -ENODEV, "Can't get DMA master node\n");
+
+       match = of_match_node(rzn1_dmac_match, dmac_node);
+       of_node_put(dmac_node);
+       if (!match)
+               return dev_err_probe(&pdev->dev, -EINVAL, "DMA master is not supported\n");
+
+       dmamux->dmarouter.dev = &pdev->dev;
+       dmamux->dmarouter.route_free = rzn1_dmamux_free;
+
+       platform_set_drvdata(pdev, dmamux);
+
+       return of_dma_router_register(mux_node, rzn1_dmamux_route_allocate,
+                                     &dmamux->dmarouter);
+}
+
+static const struct of_device_id rzn1_dmamux_match[] = {
+       { .compatible = "renesas,rzn1-dmamux" },
+       {}
+};
+
+static struct platform_driver rzn1_dmamux_driver = {
+       .driver = {
+               .name = "renesas,rzn1-dmamux",
+               .of_match_table = rzn1_dmamux_match,
+       },
+       .probe  = rzn1_dmamux_probe,
+};
+module_platform_driver(rzn1_dmamux_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com");
+MODULE_DESCRIPTION("Renesas RZ/N1 DMAMUX driver");