remoteproc: Introduce STM32 Cortex-M4 remoteproc driver

This patch introduces support of Cortex-M4 remote processor for STM32
MCU and MPU families.

Signed-off-by: Loic Pallardy <loic.pallardy@st.com>
Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>

drivers/remoteproc/Kconfig

@@ -40,6 +40,16 @@ config REMOTEPROC_SANDBOX
 	  Say 'y' here to add support for test processor which does dummy
 	  operations for sandbox platform.
 
+config REMOTEPROC_STM32_COPRO
+	bool "Support for STM32 coprocessor"
+	select REMOTEPROC
+	depends on DM
+	depends on ARCH_STM32MP
+	depends on OF_CONTROL
+	help
+	  Say 'y' here to add support for STM32 Cortex-M4 coprocessors via the
+	  remoteproc framework.
+
 config REMOTEPROC_TI_POWER
 	bool "Support for TI Power processor"
 	select REMOTEPROC

drivers/remoteproc/Makefile

@@ -10,4 +10,5 @@ obj-$(CONFIG_$(SPL_)REMOTEPROC) += rproc-uclass.o rproc-elf-loader.o
 obj-$(CONFIG_K3_SYSTEM_CONTROLLER) += k3_system_controller.o
 obj-$(CONFIG_REMOTEPROC_K3) += k3_rproc.o
 obj-$(CONFIG_REMOTEPROC_SANDBOX) += sandbox_testproc.o
+obj-$(CONFIG_REMOTEPROC_STM32_COPRO) += stm32_copro.o
 obj-$(CONFIG_REMOTEPROC_TI_POWER) += ti_power_proc.o

drivers/remoteproc/stm32_copro.c

@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2019, STMicroelectronics - All Rights Reserved
+ */
+#define pr_fmt(fmt) "%s: " fmt, __func__
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <regmap.h>
+#include <remoteproc.h>
+#include <reset.h>
+#include <syscon.h>
+#include <asm/io.h>
+
+#define RCC_GCR_HOLD_BOOT	0
+#define RCC_GCR_RELEASE_BOOT	1
+
+/**
+ * struct stm32_copro_privdata - power processor private data
+ * @reset_ctl:		reset controller handle
+ * @hold_boot_regmap:	regmap for remote processor reset hold boot
+ * @hold_boot_offset:	offset of the register controlling the hold boot setting
+ * @hold_boot_mask:	bitmask of the register for the hold boot field
+ * @is_running:		is the remote processor running
+ */
+struct stm32_copro_privdata {
+	struct reset_ctl reset_ctl;
+	struct regmap *hold_boot_regmap;
+	uint hold_boot_offset;
+	uint hold_boot_mask;
+	bool is_running;
+};
+
+/**
+ * stm32_copro_probe() - Basic probe
+ * @dev:	corresponding STM32 remote processor device
+ * @return 0 if all went ok, else corresponding -ve error
+ */
+static int stm32_copro_probe(struct udevice *dev)
+{
+	struct stm32_copro_privdata *priv;
+	struct regmap *regmap;
+	const fdt32_t *cell;
+	int len, ret;
+
+	priv = dev_get_priv(dev);
+
+	regmap = syscon_regmap_lookup_by_phandle(dev, "st,syscfg-holdboot");
+	if (IS_ERR(regmap)) {
+		dev_err(dev, "unable to find holdboot regmap (%ld)\n",
+			PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	cell = dev_read_prop(dev, "st,syscfg-holdboot", &len);
+	if (len < 3 * sizeof(fdt32_t)) {
+		dev_err(dev, "holdboot offset and mask not available\n");
+		return -EINVAL;
+	}
+
+	priv->hold_boot_regmap = regmap;
+	priv->hold_boot_offset = fdtdec_get_number(cell + 1, 1);
+	priv->hold_boot_mask = fdtdec_get_number(cell + 2, 1);
+
+	ret = reset_get_by_index(dev, 0, &priv->reset_ctl);
+	if (ret) {
+		dev_err(dev, "failed to get reset (%d)\n", ret);
+		return ret;
+	}
+
+	dev_dbg(dev, "probed\n");
+
+	return 0;
+}
+
+/**
+ * stm32_copro_set_hold_boot() - Hold boot bit management
+ * @dev:	corresponding STM32 remote processor device
+ * @hold:	hold boot value
+ * @return 0 if all went ok, else corresponding -ve error
+ */
+static int stm32_copro_set_hold_boot(struct udevice *dev, bool hold)
+{
+	struct stm32_copro_privdata *priv;
+	uint val;
+	int ret;
+
+	priv = dev_get_priv(dev);
+
+	val = hold ? RCC_GCR_HOLD_BOOT : RCC_GCR_RELEASE_BOOT;
+
+	/*
+	 * Note: shall run an SMC call (STM32_SMC_RCC) if platform is secured.
+	 * To be updated when the code for this SMC service is available which
+	 * is not the case for the time being.
+	 */
+	ret = regmap_update_bits(priv->hold_boot_regmap, priv->hold_boot_offset,
+				 priv->hold_boot_mask, val);
+	if (ret)
+		dev_err(dev, "failed to set hold boot\n");
+
+	return ret;
+}
+
+/**
+ * stm32_copro_device_to_virt() - Convert device address to virtual address
+ * @dev:	corresponding STM32 remote processor device
+ * @da:		device address
+ * @return converted virtual address
+ */
+static void *stm32_copro_device_to_virt(struct udevice *dev, ulong da)
+{
+	fdt32_t in_addr = cpu_to_be32(da);
+	u64 paddr;
+
+	paddr = dev_translate_dma_address(dev, &in_addr);
+	if (paddr == OF_BAD_ADDR) {
+		dev_err(dev, "Unable to convert address %ld\n", da);
+		return NULL;
+	}
+
+	return phys_to_virt(paddr);
+}
+
+/**
+ * stm32_copro_load() - Loadup the STM32 remote processor
+ * @dev:	corresponding STM32 remote processor device
+ * @addr:	Address in memory where image is stored
+ * @size:	Size in bytes of the image
+ * @return 0 if all went ok, else corresponding -ve error
+ */
+static int stm32_copro_load(struct udevice *dev, ulong addr, ulong size)
+{
+	struct stm32_copro_privdata *priv;
+	int ret;
+
+	priv = dev_get_priv(dev);
+
+	ret = stm32_copro_set_hold_boot(dev, true);
+	if (ret)
+		return ret;
+
+	ret = reset_assert(&priv->reset_ctl);
+	if (ret) {
+		dev_err(dev, "Unable to assert reset line (ret=%d)\n", ret);
+		return ret;
+	}
+
+	/* Support only ELF32 image */
+	ret = rproc_elf32_sanity_check(addr, size);
+	if (ret) {
+		dev_err(dev, "Invalid ELF32 image (%d)\n", ret);
+		return ret;
+	}
+
+	return rproc_elf32_load_image(dev, addr);
+}
+
+/**
+ * stm32_copro_start() - Start the STM32 remote processor
+ * @dev:	corresponding STM32 remote processor device
+ * @return 0 if all went ok, else corresponding -ve error
+ */
+static int stm32_copro_start(struct udevice *dev)
+{
+	struct stm32_copro_privdata *priv;
+	int ret;
+
+	priv = dev_get_priv(dev);
+
+	/* move hold boot from true to false start the copro */
+	ret = stm32_copro_set_hold_boot(dev, false);
+	if (ret)
+		return ret;
+
+	/*
+	 * Once copro running, reset hold boot flag to avoid copro
+	 * rebooting autonomously
+	 */
+	ret = stm32_copro_set_hold_boot(dev, true);
+	priv->is_running = !ret;
+	return ret;
+}
+
+/**
+ * stm32_copro_reset() - Reset the STM32 remote processor
+ * @dev:	corresponding STM32 remote processor device
+ * @return 0 if all went ok, else corresponding -ve error
+ */
+static int stm32_copro_reset(struct udevice *dev)
+{
+	struct stm32_copro_privdata *priv;
+	int ret;
+
+	priv = dev_get_priv(dev);
+
+	ret = stm32_copro_set_hold_boot(dev, true);
+	if (ret)
+		return ret;
+
+	ret = reset_assert(&priv->reset_ctl);
+	if (ret) {
+		dev_err(dev, "Unable to assert reset line (ret=%d)\n", ret);
+		return ret;
+	}
+
+	priv->is_running = false;
+
+	return 0;
+}
+
+/**
+ * stm32_copro_stop() - Stop the STM32 remote processor
+ * @dev:	corresponding STM32 remote processor device
+ * @return 0 if all went ok, else corresponding -ve error
+ */
+static int stm32_copro_stop(struct udevice *dev)
+{
+	return stm32_copro_reset(dev);
+}
+
+/**
+ * stm32_copro_is_running() - Is the STM32 remote processor running
+ * @dev:	corresponding STM32 remote processor device
+ * @return 1 if the remote processor is running, 0 otherwise
+ */
+static int stm32_copro_is_running(struct udevice *dev)
+{
+	struct stm32_copro_privdata *priv;
+
+	priv = dev_get_priv(dev);
+	return priv->is_running;
+}
+
+static const struct dm_rproc_ops stm32_copro_ops = {
+	.load = stm32_copro_load,
+	.start = stm32_copro_start,
+	.stop =  stm32_copro_stop,
+	.reset = stm32_copro_reset,
+	.is_running = stm32_copro_is_running,
+	.device_to_virt = stm32_copro_device_to_virt,
+};
+
+static const struct udevice_id stm32_copro_ids[] = {
+	{.compatible = "st,stm32mp1-rproc"},
+	{}
+};
+
+U_BOOT_DRIVER(stm32_copro) = {
+	.name = "stm32_m4_proc",
+	.of_match = stm32_copro_ids,
+	.id = UCLASS_REMOTEPROC,
+	.ops = &stm32_copro_ops,
+	.probe = stm32_copro_probe,
+	.priv_auto_alloc_size = sizeof(struct stm32_copro_privdata),
+};