drivers/cpu: Add generic armv8 cpu driver

Add a generic driver that binds to armv8 CPU nodes. The generic driver allows
- to enumerate CPUs present in a system, even when no other driver binds it
- generates ACPI SSDT code for each CPU
- Fill the ACPI MADT table (implemented in a follow up patch)

The newly introduced code could also be reused on other CPU drivers that are
compatible with armv8.

TEST: Booted on QEMU sbsa and verify the driver binds to CPU nodes.
      Confirmed with FWTS that all ACPI processor devices are present.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>

diff --git a/drivers/cpu/Kconfig b/drivers/cpu/Kconfig
index 5c06cd9f60e89505577208af2784862bd3402691..9c0df331d7f32e3f11195293f9df7a10dede2666 100644 (file)
--- a/drivers/cpu/Kconfig
+++ b/drivers/cpu/Kconfig
@@ -26,6 +26,12 @@ config CPU_RISCV
        help
          Support CPU cores for RISC-V architecture.
 
+config CPU_ARMV8
+       bool "Enable generic ARMv8 CPU driver"
+       depends on CPU && ARM64
+       help
+         Support CPU cores for armv8 architecture.
+
 config CPU_MICROBLAZE
        bool "Enable Microblaze CPU driver"
        depends on CPU && MICROBLAZE

diff --git a/drivers/cpu/Makefile b/drivers/cpu/Makefile
index bc75d9b974e8ec7136546929b7578481634673bb..773395693aa8b968749a2836a7c4efbdf5322a7b 100644 (file)
--- a/drivers/cpu/Makefile
+++ b/drivers/cpu/Makefile
@@ -6,10 +6,12 @@
 
 obj-$(CONFIG_CPU) += cpu-uclass.o
 
+
 obj-$(CONFIG_ARCH_BMIPS) += bmips_cpu.o
 obj-$(CONFIG_ARCH_IMX8) += imx8_cpu.o
 obj-$(CONFIG_ARCH_AT91) += at91_cpu.o
 obj-$(CONFIG_ARCH_MEDIATEK) += mtk_cpu.o
+obj-$(CONFIG_CPU_ARMV8) += armv8_cpu.o
 obj-$(CONFIG_CPU_IMX) += imx8_cpu.o
 obj-$(CONFIG_CPU_MPC83XX) += mpc83xx_cpu.o
 obj-$(CONFIG_CPU_RISCV) += riscv_cpu.o

diff --git a/drivers/cpu/armv8_cpu.c b/drivers/cpu/armv8_cpu.c
new file mode 100644 (file)
index 0000000..19f072b
--- /dev/null
+++ b/drivers/cpu/armv8_cpu.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2024 9elements GmbH
+ */
+#include <cpu.h>
+#include <dm.h>
+#include <acpi/acpigen.h>
+#include <asm/armv8/cpu.h>
+#include <dm/acpi.h>
+#include <asm/io.h>
+#include <linux/bitops.h>
+#include <linux/printk.h>
+#include <linux/sizes.h>
+
+static int armv8_cpu_get_desc(const struct udevice *dev, char *buf, int size)
+{
+       int cpuid;
+
+       cpuid = (read_midr() & MIDR_PARTNUM_MASK) >> MIDR_PARTNUM_SHIFT;
+
+       snprintf(buf, size, "CPU MIDR %04x", cpuid);
+
+       return 0;
+}
+
+static int armv8_cpu_get_info(const struct udevice *dev,
+                             struct cpu_info *info)
+{
+       info->cpu_freq = 0;
+       info->features = BIT(CPU_FEAT_L1_CACHE) | BIT(CPU_FEAT_MMU);
+
+       return 0;
+}
+
+static int armv8_cpu_get_count(const struct udevice *dev)
+{
+       return uclass_id_count(UCLASS_CPU);
+}
+
+#ifdef CONFIG_ACPIGEN
+int armv8_cpu_fill_ssdt(const struct udevice *dev, struct acpi_ctx *ctx)
+{
+       uint core_id = dev_seq(dev);
+
+       acpigen_write_processor_device(ctx, core_id);
+
+       return 0;
+}
+
+struct acpi_ops armv8_cpu_acpi_ops = {
+       .fill_ssdt      = armv8_cpu_fill_ssdt,
+};
+#endif
+
+static const struct cpu_ops cpu_ops = {
+       .get_count = armv8_cpu_get_count,
+       .get_desc  = armv8_cpu_get_desc,
+       .get_info  = armv8_cpu_get_info,
+};
+
+static const struct udevice_id cpu_ids[] = {
+       { .compatible = "arm,armv8" },
+       {}
+};
+
+U_BOOT_DRIVER(arm_cpu) = {
+       .name           = "arm-cpu",
+       .id             = UCLASS_CPU,
+       .of_match       = cpu_ids,
+       .ops            = &cpu_ops,
+       .flags          = DM_FLAG_PRE_RELOC,
+       ACPI_OPS_PTR(&armv8_cpu_acpi_ops)
+};

diff --git a/drivers/cpu/armv8_cpu.h b/drivers/cpu/armv8_cpu.h
new file mode 100644 (file)
index 0000000..2c4b025
--- /dev/null
+++ b/drivers/cpu/armv8_cpu.h
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2024 9elements GmbH
+ */
+#include <dm/acpi.h>
+#include <dm/device.h>
+
+#ifndef _ARMV8_CPU_H_
+#define _ARMV8_CPU_H_
+
+/**
+ * armv8_cpu_fill_ssdt() - Fill the SSDT
+ * Parses the FDT and writes the SSDT nodes.
+ *
+ * @dev: cpu device to generate ACPI tables for
+ * @ctx: ACPI context pointer
+ * @return:    0 if OK, or a negative error code.
+ */
+int armv8_cpu_fill_ssdt(const struct udevice *dev, struct acpi_ctx *ctx);
+
+#endif
\ No newline at end of file