So far most of the drivers with the MBUS quirks had to duplicate the
code to deal with DT compatibility and enforcing the DMA offsets.
Let's move for a more maintainable solution by putting everything in a
notifier that would take care of setting up the DMA offsets for all the
MBUS devices.
Suggested-by: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
---
drivers/soc/sunxi/Kconfig | 8 ++
drivers/soc/sunxi/Makefile | 1 +
drivers/soc/sunxi/sunxi_mbus.c | 132 +++++++++++++++++++++++++++++++++
3 files changed, 141 insertions(+)
create mode 100644 drivers/soc/sunxi/sunxi_mbus.c
diff --git a/drivers/soc/sunxi/Kconfig b/drivers/soc/sunxi/Kconfig
index f10fd6cae13e..1fef0e711056 100644
--- a/drivers/soc/sunxi/Kconfig
+++ b/drivers/soc/sunxi/Kconfig
@@ -2,6 +2,14 @@
#
# Allwinner sunXi SoC drivers
#
+
+config SUNXI_MBUS
+ bool
+ default ARCH_SUNXI
+ help
+ Say y to enable the fixups needed to support the Allwinner
+ MBUS DMA quirks.
+
config SUNXI_SRAM
bool
default ARCH_SUNXI
diff --git a/drivers/soc/sunxi/Makefile b/drivers/soc/sunxi/Makefile
index 7816fbbec387..549159571d4f 100644
--- a/drivers/soc/sunxi/Makefile
+++ b/drivers/soc/sunxi/Makefile
@@ -1,2 +1,3 @@
# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_SUNXI_MBUS) += sunxi_mbus.o
obj-$(CONFIG_SUNXI_SRAM) += sunxi_sram.o
diff --git a/drivers/soc/sunxi/sunxi_mbus.c b/drivers/soc/sunxi/sunxi_mbus.c
new file mode 100644
index 000000000000..a9d077f73c3a
--- /dev/null
+++ b/drivers/soc/sunxi/sunxi_mbus.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2020 Maxime Ripard <maxime@xxxxxxxxxx> */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+static const char * const sunxi_mbus_devices[] = {
+ /*
+ * The display engine virtual devices are not strictly speaking
+ * connected to the MBUS, but since DRM will perform all the
+ * memory allocations and DMA operations through that device, we
+ * need to have the quirk on those devices too.
+ */
+ "allwinner,sun4i-a10-display-engine",
+ "allwinner,sun5i-a10s-display-engine",
+ "allwinner,sun5i-a13-display-engine",
+ "allwinner,sun6i-a31-display-engine",
+ "allwinner,sun6i-a31s-display-engine",
+ "allwinner,sun7i-a20-display-engine",
+ "allwinner,sun8i-a23-display-engine",
+ "allwinner,sun8i-a33-display-engine",
+ "allwinner,sun8i-a83t-display-engine",
+ "allwinner,sun8i-h3-display-engine",
+ "allwinner,sun8i-r40-display-engine",
+ "allwinner,sun8i-v3s-display-engine",
+ "allwinner,sun9i-a80-display-engine",
+ "allwinner,sun50i-a64-display-engine",
+
+ /*
+ * And now we have the regular devices connected to the MBUS
+ * (that we know of).
+ */
+ "allwinner,sun4i-a10-csi1",
+ "allwinner,sun4i-a10-display-backend",
+ "allwinner,sun4i-a10-display-frontend",
+ "allwinner,sun4i-a10-video-engine",
+ "allwinner,sun5i-a13-display-backend",
+ "allwinner,sun5i-a13-video-engine",
+ "allwinner,sun6i-a31-csi",
+ "allwinner,sun6i-a31-display-backend",
+ "allwinner,sun7i-a20-csi0",
+ "allwinner,sun7i-a20-display-backend",
+ "allwinner,sun7i-a20-display-frontend",
+ "allwinner,sun7i-a20-video-engine",
+ "allwinner,sun8i-a23-display-backend",
+ "allwinner,sun8i-a23-display-frontend",
+ "allwinner,sun8i-a33-display-backend",
+ "allwinner,sun8i-a33-display-frontend",
+ "allwinner,sun8i-a33-video-engine",
+ "allwinner,sun8i-a83t-csi",
+ "allwinner,sun8i-h3-csi",
+ "allwinner,sun8i-h3-video-engine",
+ "allwinner,sun8i-v3s-csi",
+ "allwinner,sun9i-a80-display-backend",
+ "allwinner,sun50i-a64-csi",
+ "allwinner,sun50i-a64-video-engine",
+ "allwinner,sun50i-h5-video-engine",
+ NULL,
+};
+
+static int sunxi_mbus_notifier(struct notifier_block *nb,
+ unsigned long event, void *__dev)
+{
+ struct device *dev = __dev;
+ int ret;
+
+ if (event != BUS_NOTIFY_ADD_DEVICE)
+ return NOTIFY_DONE;
+
+ /*
+ * Only the devices that need a large memory bandwidth do DMA
+ * directly over the memory bus (called MBUS), instead of going
+ * through the regular system bus.
+ */
+ if (!of_device_compatible_match(dev->of_node, sunxi_mbus_devices))
+ return NOTIFY_DONE;
+
+ /*
+ * Devices with an interconnects property have the MBUS
+ * relationship described in their DT and dealt with by
+ * of_dma_configure, so we can just skip them.
+ *
+ * Older DTs or SoCs who are not clearly understood need to set
+ * that DMA offset though.
+ */
+ if (of_find_property(dev->of_node, "interconnects", NULL))
+ return NOTIFY_DONE;
+
+ ret = dma_direct_set_offset(dev, PHYS_OFFSET, 0, SZ_4G);
+ if (ret)
+ dev_err(dev, "Couldn't setup our DMA offset: %d\n", ret);
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block sunxi_mbus_nb = {
+ .notifier_call = sunxi_mbus_notifier,
+};
+
+static const char * const sunxi_mbus_platforms[] __initconst = {
+ "allwinner,sun4i-a10",
+ "allwinner,sun5i-a10s",
+ "allwinner,sun5i-a13",
+ "allwinner,sun6i-a31",
+ "allwinner,sun7i-a20",
+ "allwinner,sun8i-a23",
+ "allwinner,sun8i-a33",
+ "allwinner,sun8i-a83t",
+ "allwinner,sun8i-h3",
+ "allwinner,sun8i-r40",
+ "allwinner,sun8i-v3",
+ "allwinner,sun8i-v3s",
+ "allwinner,sun9i-a80",
+ "allwinner,sun50i-a64",
+ "allwinner,sun50i-h5",
+ "nextthing,gr8",
+ NULL,
+};
+
+static int __init sunxi_mbus_init(void)
+{
+ if (!of_device_compatible_match(of_root, sunxi_mbus_platforms))
+ return 0;
+
+ bus_register_notifier(&platform_bus_type, &sunxi_mbus_nb);
+ return 0;
+}
+arch_initcall(sunxi_mbus_init);
--
2.28.0
