remoteproc: Add a driver for the Allwinner AR100

Signed-off-by: Samuel Holland <samuel@sholland.org>

drivers/remoteproc/Kconfig

@@ -41,6 +41,15 @@ config REMOTEPROC_STM32_COPRO
 	  Say 'y' here to add support for STM32 Cortex-M4 coprocessors via the
 	  remoteproc framework.
 
+config REMOTEPROC_SUN6I_AR100
+	bool "Support for Allwinner AR100 SCP"
+	select REMOTEPROC
+	depends on ARCH_SUNXI
+	help
+	  Say 'y' here to support Allwinner's AR100 System Control Processor
+	  (SCP), found in various sun6i/sun8i/sun50i family SoCs, through the
+	  remoteproc framework.
+
 config REMOTEPROC_TI_K3_ARM64
 	bool "Support for TI's K3 based ARM64 remoteproc driver"
 	select REMOTEPROC

drivers/remoteproc/Makefile

@@ -10,6 +10,7 @@ obj-$(CONFIG_$(SPL_)REMOTEPROC) += rproc-uclass.o rproc-elf-loader.o
 obj-$(CONFIG_K3_SYSTEM_CONTROLLER) += k3_system_controller.o
 obj-$(CONFIG_REMOTEPROC_SANDBOX) += sandbox_testproc.o
 obj-$(CONFIG_REMOTEPROC_STM32_COPRO) += stm32_copro.o
+obj-$(CONFIG_REMOTEPROC_SUN6I_AR100) += sun6i_ar100_rproc.o
 obj-$(CONFIG_REMOTEPROC_TI_K3_ARM64) += ti_k3_arm64_rproc.o
 obj-$(CONFIG_REMOTEPROC_TI_K3_DSP) += ti_k3_dsp_rproc.o
 obj-$(CONFIG_REMOTEPROC_TI_K3_R5F) += ti_k3_r5f_rproc.o

drivers/remoteproc/sun6i_ar100_rproc.c

@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <dm.h>
+#include <errno.h>
+#include <remoteproc.h>
+#include <asm/io.h>
+
+#define SUNXI_SCP_MAGIC			0xb4400012
+
+#define OR1K_VEC_FIRST			0x01
+#define OR1K_VEC_LAST			0x0e
+#define OR1K_VEC_ADDR(n)		(0x100 * (n))
+
+struct sun6i_ar100_rproc_priv {
+	void	*cfg_base;
+	ulong	sram_base;
+};
+
+static int sun6i_ar100_rproc_load(struct udevice *dev, ulong addr, ulong size)
+{
+	struct sun6i_ar100_rproc_priv *priv = dev_get_priv(dev);
+
+	/* Check for a valid SCP firmware. */
+	if (readl_relaxed(addr) != SUNXI_SCP_MAGIC)
+		return -ENOENT;
+
+	/* Program exception vectors to the firmware entry point. */
+	for (u32 i = OR1K_VEC_FIRST; i <= OR1K_VEC_LAST; ++i) {
+		ulong vector = priv->sram_base + OR1K_VEC_ADDR(i);
+		ulong offset = addr - vector;
+
+		writel_relaxed(offset >> 2, vector);
+	}
+
+	return 0;
+}
+
+static int sun6i_ar100_rproc_start(struct udevice *dev)
+{
+	struct sun6i_ar100_rproc_priv *priv = dev_get_priv(dev);
+
+	setbits_le32(priv->cfg_base, BIT(0));
+
+	return 0;
+}
+
+static int sun6i_ar100_rproc_stop(struct udevice *dev)
+{
+	struct sun6i_ar100_rproc_priv *priv = dev_get_priv(dev);
+
+	clrbits_le32(priv->cfg_base, BIT(0));
+
+	return 0;
+}
+
+static int sun6i_ar100_rproc_reset(struct udevice *dev)
+{
+	int ret;
+
+	ret = sun6i_ar100_rproc_stop(dev);
+	if (ret)
+		return ret;
+
+	return sun6i_ar100_rproc_start(dev);
+}
+
+static int sun6i_ar100_rproc_is_running(struct udevice *dev)
+{
+	struct sun6i_ar100_rproc_priv *priv = dev_get_priv(dev);
+
+	return !(readl_relaxed(priv->cfg_base) & BIT(0));
+}
+
+static const struct dm_rproc_ops sun6i_ar100_rproc_ops = {
+	.load		= sun6i_ar100_rproc_load,
+	.start		= sun6i_ar100_rproc_start,
+	.stop		= sun6i_ar100_rproc_stop,
+	.reset		= sun6i_ar100_rproc_reset,
+	.is_running	= sun6i_ar100_rproc_is_running,
+};
+
+static int sun6i_ar100_rproc_probe(struct udevice *dev)
+{
+	struct sun6i_ar100_rproc_priv *priv = dev_get_priv(dev);
+	struct ofnode_phandle_args sram_handle;
+	int ret;
+
+	priv->cfg_base = dev_read_addr_ptr(dev);
+
+	ret = dev_read_phandle_with_args(dev, "sram", NULL, 0, 0, &sram_handle);
+	if (ret)
+		return ret;
+
+	priv->sram_base = ofnode_get_addr(sram_handle.node);
+
+	return 0;
+}
+
+static const struct udevice_id sun6i_ar100_rproc_ids[] = {
+	{ .compatible = "allwinner,sun6i-a31-ar100" },
+	{ }
+};
+
+U_BOOT_DRIVER(sun6i_ar100_rproc) = {
+	.name		= "sun6i_ar100_rproc",
+	.id		= UCLASS_REMOTEPROC,
+	.of_match	= sun6i_ar100_rproc_ids,
+	.probe		= sun6i_ar100_rproc_probe,
+	.priv_auto	= sizeof(struct sun6i_ar100_rproc_priv),
+	.ops		= &sun6i_ar100_rproc_ops,
+};