remoteproc: renesas: Add Renesas R-Car Gen4 remote processor driver
Add R-Car Gen4 APMU controller remoteproc driver capable of starting
the Cortex-R52 cores in Renesas R8A779G0 V4H/V4M SoC. The APMU IP is
in fact a power management unit capable of additional operations, but
those are not used by U-Boot so far.
This requires slight adjustment to the SPL entry point code, as that
is being executed on the Cortex-R52 #0 and the Cortex-R52 #0 enters an
endless loop once it starts the rest of the SPL on Cortex-A76 core.
The endless loop now checks for content of APMU CRBARP registers and
tests whether valid VLD_BARP and BAREN_VALID bits are set, if so, the
Cortex-R52 core exits the endless loop and jumps to address started
in CRBARP[31:18] register in ARM mode, which is a trampoline code to
jump to the final entry point.
The trampoline code is in place to avoid limitation of CRBARP[31:18]
address field, which limits the core start address to memory addresses
aligned to 0x40000 or 256 kiB . The trampoline is placed at 0x40000
aligned address and jumps to the final entry point, which can be at
an address with arbitrary alignment at instruction granularity.
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/drivers/remoteproc/renesas_apmu.c b/drivers/remoteproc/renesas_apmu.c
new file mode 100644
index 0000000..32d138e
--- /dev/null
+++ b/drivers/remoteproc/renesas_apmu.c
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2024 Renesas Electronics Corp.
+ */
+
+#include <asm/io.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <errno.h>
+#include <hang.h>
+#include <linux/iopoll.h>
+#include <linux/sizes.h>
+#include <malloc.h>
+#include <remoteproc.h>
+
+/* R-Car V4H/V4M contain 3 clusters / 3 cores */
+#define RCAR4_CR52_CORES 3
+
+/* Reset Control Register for Cortex-R52 #n */
+#define APMU_CRRSTCTRL(n) (0x304 + ((n) * 0x40))
+#define APMU_CRRSTCTRL_CR52RST BIT(0)
+
+/* Base Address Register for Cortex-R52 #n */
+#define APMU_CRBARP(n) (0x33c + ((n) * 0x40))
+#define APMU_CRBARP_CR_VLD_BARP BIT(0)
+#define APMU_CRBARP_CR_BAREN_VALID BIT(4)
+#define APMU_CRBARP_CR_RBAR_MASK 0xfffc0000
+#define APMU_CRBARP_CR_RBAR_ALIGN 0x40000
+
+/**
+ * struct renesas_apmu_rproc_privdata - remote processor private data
+ * @regs: controller registers
+ * @core_id: CPU core id
+ * @trampoline: jump trampoline code
+ */
+struct renesas_apmu_rproc_privdata {
+ void __iomem *regs;
+ ulong core_id;
+ u32 *trampoline;
+};
+
+/*
+ * CRBARP address is aligned to 0x40000 / 256 kiB , this trampoline
+ * allows arbitrary address alignment at instruction granularity.
+ */
+static const u32 renesas_apmu_rproc_trampoline[4] = {
+ 0xe59f0004, /* ldr r0, [pc, #4] */
+ 0xe1a0f000, /* mov pc, r0 */
+ 0xeafffffe, /* 1: b 1b */
+ 0xabcd1234 /* jump target (rewritten on load) */
+};
+
+/**
+ * renesas_apmu_rproc_load() - Load the remote processor
+ * @dev: corresponding 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 renesas_apmu_rproc_load(struct udevice *dev, ulong addr, ulong size)
+{
+ struct renesas_apmu_rproc_privdata *priv = dev_get_priv(dev);
+ u32 trampolineaddr = (u32)(uintptr_t)(priv->trampoline);
+
+ priv->trampoline[3] = addr;
+ flush_dcache_range(trampolineaddr,
+ trampolineaddr +
+ sizeof(renesas_apmu_rproc_trampoline));
+
+ /* CR52 boot address set */
+ writel(trampolineaddr | APMU_CRBARP_CR_VLD_BARP,
+ priv->regs + APMU_CRBARP(priv->core_id));
+ writel(trampolineaddr | APMU_CRBARP_CR_VLD_BARP | APMU_CRBARP_CR_BAREN_VALID,
+ priv->regs + APMU_CRBARP(priv->core_id));
+
+ return 0;
+}
+
+/**
+ * renesas_apmu_rproc_start() - Start the remote processor
+ * @dev: corresponding remote processor device
+ *
+ * Return: 0 if all went ok, else corresponding -ve error
+ */
+static int renesas_apmu_rproc_start(struct udevice *dev)
+{
+ struct renesas_apmu_rproc_privdata *priv = dev_get_priv(dev);
+
+ /* Clear APMU_CRRSTCTRL_CR52RST, the only bit in this register */
+ writel(0, priv->regs + APMU_CRRSTCTRL(priv->core_id));
+
+ return 0;
+}
+
+/**
+ * renesas_apmu_rproc_stop() - Stop the remote processor
+ * @dev: corresponding remote processor device
+ *
+ * Return: 0 if all went ok, else corresponding -ve error
+ */
+static int renesas_apmu_rproc_stop(struct udevice *dev)
+{
+ struct renesas_apmu_rproc_privdata *priv = dev_get_priv(dev);
+
+ /* Set APMU_CRRSTCTRL_CR52RST, the only bit in this register */
+ writel(APMU_CRRSTCTRL_CR52RST,
+ priv->regs + APMU_CRRSTCTRL(priv->core_id));
+
+ return 0;
+}
+
+/**
+ * renesas_apmu_rproc_reset() - Reset the remote processor
+ * @dev: corresponding remote processor device
+ *
+ * Return: 0 if all went ok, else corresponding -ve error
+ */
+static int renesas_apmu_rproc_reset(struct udevice *dev)
+{
+ renesas_apmu_rproc_stop(dev);
+ renesas_apmu_rproc_start(dev);
+ return 0;
+}
+
+/**
+ * renesas_apmu_rproc_is_running() - Is the remote processor running
+ * @dev: corresponding remote processor device
+ *
+ * Return: 0 if the remote processor is running, 1 otherwise
+ */
+static int renesas_apmu_rproc_is_running(struct udevice *dev)
+{
+ struct renesas_apmu_rproc_privdata *priv = dev_get_priv(dev);
+
+ return readl(priv->regs + APMU_CRRSTCTRL(priv->core_id)) &
+ APMU_CRRSTCTRL_CR52RST;
+}
+
+/**
+ * renesas_apmu_rproc_init() - Initialize the remote processor CRBAR registers
+ * @dev: corresponding remote processor device
+ *
+ * Return: 0 if all went ok, else corresponding -ve error
+ */
+static int renesas_apmu_rproc_init(struct udevice *dev)
+{
+ struct renesas_apmu_rproc_privdata *priv = dev_get_priv(dev);
+
+ /* If the core is running already, do nothing. */
+ if (renesas_apmu_rproc_is_running(dev))
+ return 0;
+
+ /* Clear and invalidate CRBARP content */
+ writel(0, priv->regs + APMU_CRBARP(priv->core_id));
+
+ return 0;
+}
+
+/**
+ * renesas_apmu_rproc_device_to_virt() - Convert device address to virtual address
+ * @dev: corresponding remote processor device
+ * @da: device address
+ * @size: Size of the memory region @da is pointing to
+ *
+ * Return: converted virtual address
+ */
+static void *renesas_apmu_rproc_device_to_virt(struct udevice *dev, ulong da,
+ ulong size)
+{
+ /*
+ * The Cortex R52 and A76 share the same address space,
+ * this operation is a no-op.
+ */
+ return (void *)da;
+}
+
+static const struct dm_rproc_ops renesas_apmu_rproc_ops = {
+ .init = renesas_apmu_rproc_init,
+ .load = renesas_apmu_rproc_load,
+ .start = renesas_apmu_rproc_start,
+ .stop = renesas_apmu_rproc_stop,
+ .reset = renesas_apmu_rproc_reset,
+ .is_running = renesas_apmu_rproc_is_running,
+ .device_to_virt = renesas_apmu_rproc_device_to_virt,
+};
+
+/**
+ * renesas_apmu_rproc_of_to_plat() - Convert OF data to platform data
+ * @dev: corresponding remote processor device
+ *
+ * Return: 0 if all went ok, else corresponding -ve error
+ */
+static int renesas_apmu_rproc_of_to_plat(struct udevice *dev)
+{
+ struct renesas_apmu_rproc_privdata *priv = dev_get_priv(dev);
+
+ priv->core_id = dev_get_driver_data(dev);
+
+ priv->regs = dev_read_addr_ptr(dev);
+ if (!priv->regs)
+ return -EINVAL;
+
+ priv->trampoline = memalign(APMU_CRBARP_CR_RBAR_ALIGN,
+ sizeof(renesas_apmu_rproc_trampoline));
+ if (!priv->trampoline)
+ return -ENOMEM;
+
+ memcpy(priv->trampoline, renesas_apmu_rproc_trampoline,
+ sizeof(renesas_apmu_rproc_trampoline));
+
+ return 0;
+}
+
+U_BOOT_DRIVER(renesas_apmu_cr52) = {
+ .name = "rcar-apmu-cr52",
+ .id = UCLASS_REMOTEPROC,
+ .ops = &renesas_apmu_rproc_ops,
+ .of_to_plat = renesas_apmu_rproc_of_to_plat,
+ .priv_auto = sizeof(struct renesas_apmu_rproc_privdata),
+};
+
+/**
+ * renesas_apmu_rproc_bind() - Bind rproc driver to each core control
+ * @dev: corresponding remote processor parent device
+ *
+ * Return: 0 if all went ok, else corresponding -ve error
+ */
+static int renesas_apmu_rproc_bind(struct udevice *parent)
+{
+ const ulong cr52cores = RCAR4_CR52_CORES;
+ ofnode pnode = dev_ofnode(parent);
+ struct udevice *cdev;
+ struct driver *cdrv;
+ char name[32];
+ ulong i;
+ int ret;
+
+ cdrv = lists_driver_lookup_name("rcar-apmu-cr52");
+ if (!cdrv)
+ return -ENOENT;
+
+ for (i = 0; i < cr52cores; i++) {
+ snprintf(name, sizeof(name), "rcar-apmu-cr52.%ld", i);
+ ret = device_bind_with_driver_data(parent, cdrv, strdup(name),
+ i, pnode, &cdev);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct udevice_id renesas_apmu_rproc_ids[] = {
+ { .compatible = "renesas,r8a779g0-cr52" },
+ { .compatible = "renesas,r8a779h0-cr52" },
+ { }
+};
+
+U_BOOT_DRIVER(renesas_apmu_rproc) = {
+ .name = "rcar-apmu-rproc",
+ .of_match = renesas_apmu_rproc_ids,
+ .id = UCLASS_NOP,
+ .bind = renesas_apmu_rproc_bind,
+};