Merge tag 'jh7100-for-5.17' of https://github.com/esmil/linux into arm/newsoc

Basic StarFive JH7100 RISC-V SoC support

This adds support for the StarFive JH7100 RISC-V SoC. The SoC has many
devices that need non-coherent DMA operations to work which isn't
upstream yet[1], so this just adds basic support to boot up, get a
serial console, blink an LED and reboot itself. Unlike the Allwinner D1
this chip doesn't use any extra pagetable bits, but instead the DDR RAM
appears twice in the memory map, with and without the cache.

The JH7100 is a test chip for the upcoming JH7110 and about 300 BeagleV
Starlight Beta boards were sent out with them as part of a now cancelled
BeagleBoard.org project. However StarFive has produced more of the
JH7100s and will be selling VisionFive boards with them soon[2].

[1]: https://lore.kernel.org/linux-riscv/20210723214031.3251801-2-atish.patra@wdc.com/
[2]: https://www.cnx-software.com/2021/12/09/starfive-visionfive-single-board-computer-for-sale-accelerating-risc-v-ecosystem-development/

* tag 'jh7100-for-5.17' of https://github.com/esmil/linux:
  RISC-V: Add BeagleV Starlight Beta device tree
  RISC-V: Add initial StarFive JH7100 device tree
  serial: 8250_dw: Add StarFive JH7100 quirk
  dt-bindings: serial: snps-dw-apb-uart: Add JH7100 uarts
  pinctrl: starfive: Add pinctrl driver for StarFive SoCs
  dt-bindings: pinctrl: Add StarFive JH7100 bindings
  dt-bindings: pinctrl: Add StarFive pinctrl definitions
  reset: starfive-jh7100: Add StarFive JH7100 reset driver
  dt-bindings: reset: Add Starfive JH7100 reset bindings
  dt-bindings: reset: Add StarFive JH7100 reset definitions
  clk: starfive: Add JH7100 clock generator driver
  dt-bindings: clock: starfive: Add JH7100 bindings
  dt-bindings: clock: starfive: Add JH7100 clock definitions
  dt-bindings: interrupt-controller: Add StarFive JH7100 plic
  dt-bindings: timer: Add StarFive JH7100 clint
  RISC-V: Add StarFive SoC Kconfig option

Link: https://lore.kernel.org/r/20211216164205.286138-1-kernel@esmil.dk
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

3 files changed, 180 insertions, 0 deletions

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 85024eb1d2ea..6f8ba0ddc05f 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -224,6 +224,13 @@ config RESET_SOCFPGA
 	  This enables the reset driver for the SoCFPGA ARMv7 platforms. This
 	  driver gets initialized early during platform init calls.
 
+config RESET_STARFIVE_JH7100
+	bool "StarFive JH7100 Reset Driver"
+	depends on SOC_STARFIVE || COMPILE_TEST
+	default SOC_STARFIVE
+	help
+	  This enables the reset controller driver for the StarFive JH7100 SoC.
+
 config RESET_SUNXI
 	bool "Allwinner SoCs Reset Driver" if COMPILE_TEST && !ARCH_SUNXI
 	default ARCH_SUNXI
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 21d46d8869ff..bd0a97be18b5 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_RESET_RZG2L_USBPHY_CTRL) += reset-rzg2l-usbphy-ctrl.o
 obj-$(CONFIG_RESET_SCMI) += reset-scmi.o
 obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o
 obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
+obj-$(CONFIG_RESET_STARFIVE_JH7100) += reset-starfive-jh7100.o
 obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
 obj-$(CONFIG_RESET_TI_SCI) += reset-ti-sci.o
 obj-$(CONFIG_RESET_TI_SYSCON) += reset-ti-syscon.o
diff --git a/drivers/reset/reset-starfive-jh7100.c b/drivers/reset/reset-starfive-jh7100.c
new file mode 100644
index 000000000000..e28a19d271cb
--- /dev/null
+++ b/drivers/reset/reset-starfive-jh7100.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Reset driver for the StarFive JH7100 SoC
+ *
+ * Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk>
+ */
+
+#include <linux/bitmap.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/spinlock.h>
+
+#include <dt-bindings/reset/starfive-jh7100.h>
+
+/* register offsets */
+#define JH7100_RESET_ASSERT0	0x00
+#define JH7100_RESET_ASSERT1	0x04
+#define JH7100_RESET_ASSERT2	0x08
+#define JH7100_RESET_ASSERT3	0x0c
+#define JH7100_RESET_STATUS0	0x10
+#define JH7100_RESET_STATUS1	0x14
+#define JH7100_RESET_STATUS2	0x18
+#define JH7100_RESET_STATUS3	0x1c
+
+/*
+ * Writing a 1 to the n'th bit of the m'th ASSERT register asserts
+ * line 32m + n, and writing a 0 deasserts the same line.
+ * Most reset lines have their status inverted so a 0 bit in the STATUS
+ * register means the line is asserted and a 1 means it's deasserted. A few
+ * lines don't though, so store the expected value of the status registers when
+ * all lines are asserted.
+ */
+static const u64 jh7100_reset_asserted[2] = {
+	/* STATUS0 */
+	BIT_ULL_MASK(JH7100_RST_U74) |
+	BIT_ULL_MASK(JH7100_RST_VP6_DRESET) |
+	BIT_ULL_MASK(JH7100_RST_VP6_BRESET) |
+	/* STATUS1 */
+	BIT_ULL_MASK(JH7100_RST_HIFI4_DRESET) |
+	BIT_ULL_MASK(JH7100_RST_HIFI4_BRESET),
+	/* STATUS2 */
+	BIT_ULL_MASK(JH7100_RST_E24) |
+	/* STATUS3 */
+	0,
+};
+
+struct jh7100_reset {
+	struct reset_controller_dev rcdev;
+	/* protect registers against concurrent read-modify-write */
+	spinlock_t lock;
+	void __iomem *base;
+};
+
+static inline struct jh7100_reset *
+jh7100_reset_from(struct reset_controller_dev *rcdev)
+{
+	return container_of(rcdev, struct jh7100_reset, rcdev);
+}
+
+static int jh7100_reset_update(struct reset_controller_dev *rcdev,
+			       unsigned long id, bool assert)
+{
+	struct jh7100_reset *data = jh7100_reset_from(rcdev);
+	unsigned long offset = BIT_ULL_WORD(id);
+	u64 mask = BIT_ULL_MASK(id);
+	void __iomem *reg_assert = data->base + JH7100_RESET_ASSERT0 + offset * sizeof(u64);
+	void __iomem *reg_status = data->base + JH7100_RESET_STATUS0 + offset * sizeof(u64);
+	u64 done = jh7100_reset_asserted[offset] & mask;
+	u64 value;
+	unsigned long flags;
+	int ret;
+
+	if (!assert)
+		done ^= mask;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	value = readq(reg_assert);
+	if (assert)
+		value |= mask;
+	else
+		value &= ~mask;
+	writeq(value, reg_assert);
+
+	/* if the associated clock is gated, deasserting might otherwise hang forever */
+	ret = readq_poll_timeout_atomic(reg_status, value, (value & mask) == done, 0, 1000);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+	return ret;
+}
+
+static int jh7100_reset_assert(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	return jh7100_reset_update(rcdev, id, true);
+}
+
+static int jh7100_reset_deassert(struct reset_controller_dev *rcdev,
+				 unsigned long id)
+{
+	return jh7100_reset_update(rcdev, id, false);
+}
+
+static int jh7100_reset_reset(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	int ret;
+
+	ret = jh7100_reset_assert(rcdev, id);
+	if (ret)
+		return ret;
+
+	return jh7100_reset_deassert(rcdev, id);
+}
+
+static int jh7100_reset_status(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	struct jh7100_reset *data = jh7100_reset_from(rcdev);
+	unsigned long offset = BIT_ULL_WORD(id);
+	u64 mask = BIT_ULL_MASK(id);
+	void __iomem *reg_status = data->base + JH7100_RESET_STATUS0 + offset * sizeof(u64);
+	u64 value = readq(reg_status);
+
+	return !((value ^ jh7100_reset_asserted[offset]) & mask);
+}
+
+static const struct reset_control_ops jh7100_reset_ops = {
+	.assert		= jh7100_reset_assert,
+	.deassert	= jh7100_reset_deassert,
+	.reset		= jh7100_reset_reset,
+	.status		= jh7100_reset_status,
+};
+
+static int __init jh7100_reset_probe(struct platform_device *pdev)
+{
+	struct jh7100_reset *data;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(data->base))
+		return PTR_ERR(data->base);
+
+	data->rcdev.ops = &jh7100_reset_ops;
+	data->rcdev.owner = THIS_MODULE;
+	data->rcdev.nr_resets = JH7100_RSTN_END;
+	data->rcdev.dev = &pdev->dev;
+	data->rcdev.of_node = pdev->dev.of_node;
+	spin_lock_init(&data->lock);
+
+	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
+}
+
+static const struct of_device_id jh7100_reset_dt_ids[] = {
+	{ .compatible = "starfive,jh7100-reset" },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver jh7100_reset_driver = {
+	.driver = {
+		.name = "jh7100-reset",
+		.of_match_table = jh7100_reset_dt_ids,
+		.suppress_bind_attrs = true,
+	},
+};
+builtin_platform_driver_probe(jh7100_reset_driver, jh7100_reset_probe);