reset: Add RPi5 rescal reset facilities

A driver for Broadcom rescal reset controllers ported from
linux/drivers/reset/reset-brcmstb-rescal.c to U-Boot.

Signed-off-by: Torsten Duwe <duwe@suse.de>
Co-authored-by: Oleksii Moisieiev <oleksii_moisieiev@epam.com>
Tested-by: Pedro Falcato <pfalcato@suse.de>

configs/rpi_arm64_defconfig

@@ -45,6 +45,7 @@ CONFIG_PCI_BRCMSTB=y
 CONFIG_PINCTRL=y
 # CONFIG_PINCTRL_GENERIC is not set
 CONFIG_RESET_BRCMSTB=y
+CONFIG_RESET_BRCMSTB_RESCAL=y
 CONFIG_DM_RNG=y
 CONFIG_RNG_IPROC200=y
 # CONFIG_REQUIRE_SERIAL_CONSOLE is not set

drivers/reset/Kconfig

@@ -72,6 +72,14 @@ config RESET_BRCMSTB
 	  If you wish to use reset resources managed by the Broadcom
 	  Reset Controller, say Y here. Otherwise, say N.
 
+config RESET_BRCMSTB_RESCAL
+	depends on ARCH_BCM283X
+	bool "Generic Rescal Reset controller driver for Broadcom"
+	help
+	  Support rescal reset controller on Broadcom.
+	  If you wish to use reset resources managed by the Broadcom
+	  Reset Controller, say Y here. Otherwise, say N.
+
 config RESET_UNIPHIER
 	bool "Reset controller driver for UniPhier SoCs"
 	depends on ARCH_UNIPHIER

drivers/reset/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_RESET_TI_SCI) += reset-ti-sci.o
 obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
 obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
 obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
+obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
 obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
 obj-$(CONFIG_RESET_AST2500) += reset-ast2500.o
 obj-$(CONFIG_RESET_AST2600) += reset-ast2600.o

drivers/reset/reset-brcmstb-rescal.c

@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Broadcom STB generic reset controller
+ *
+ * Copyright (C) 2024 EPAM Systems
+ * Moved from linux kernel:
+ * Copyright (C) 2018-2020 Broadcom
+ */
+
+#include <asm/io.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <errno.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/iopoll.h>
+#include <log.h>
+#include <malloc.h>
+#include <reset-uclass.h>
+
+#define BRCM_RESCAL_START 0x0
+#define BRCM_RESCAL_START_BIT BIT(0)
+#define BRCM_RESCAL_CTRL 0x4
+#define BRCM_RESCAL_STATUS 0x8
+#define BRCM_RESCAL_STATUS_BIT BIT(0)
+
+struct brcm_rescal_reset {
+	void __iomem *base;
+};
+
+/* Also doubles a deassert */
+static int brcm_rescal_reset_set(struct reset_ctl *rst)
+{
+	struct brcm_rescal_reset *data = dev_get_priv(rst->dev);
+	void __iomem *base = data->base;
+	u32 reg;
+	int ret;
+
+	reg = readl(base + BRCM_RESCAL_START);
+	writel(reg | BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
+	reg = readl(base + BRCM_RESCAL_START);
+	if (!(reg & BRCM_RESCAL_START_BIT)) {
+		dev_err(rst->dev, "failed to start SATA/PCIe rescal\n");
+		return -EIO;
+	}
+
+	ret = readl_poll_timeout(base + BRCM_RESCAL_STATUS, reg,
+				 (reg & BRCM_RESCAL_STATUS_BIT), 100);
+	if (ret) {
+		dev_err(rst->dev, "time out on SATA/PCIe rescal\n");
+		return ret;
+	}
+
+	reg = readl(base + BRCM_RESCAL_START);
+	writel(reg & ~BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
+
+	dev_dbg(rst->dev, "SATA/PCIe rescal success\n");
+	return 0;
+}
+
+/* A dummy function - deassert/reset does all the work */
+static int brcm_rescal_reset_assert(struct reset_ctl *rst)
+{
+	return 0;
+}
+
+static int brcm_rescal_reset_xlate(struct reset_ctl *reset_ctl,
+				   struct ofnode_phandle_args *args)
+{
+	/* This is needed if #reset-cells == 0. */
+	return 0;
+}
+
+static const struct reset_ops brcm_rescal_reset_ops = {
+	.rst_deassert = brcm_rescal_reset_set,
+	.rst_assert = brcm_rescal_reset_assert,
+	.of_xlate = brcm_rescal_reset_xlate,
+};
+
+static int brcm_rescal_reset_probe(struct udevice *dev)
+{
+	struct brcm_rescal_reset *data = dev_get_priv(dev);
+
+	data->base = dev_remap_addr(dev);
+	if (!data->base)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct udevice_id brcm_rescal_reset_of_match[] = {
+	{.compatible = "brcm,bcm7216-pcie-sata-rescal"},
+	{},
+};
+
+U_BOOT_DRIVER(brcmstb_reset_rescal) = {
+	.name = "brcmstb-reset-rescal",
+	.id = UCLASS_RESET,
+	.of_match = brcm_rescal_reset_of_match,
+	.ops = &brcm_rescal_reset_ops,
+	.probe = brcm_rescal_reset_probe,
+	.priv_auto = sizeof(struct brcm_rescal_reset),
+};