This adds a driver for RISC-V CPU. Note the driver will bind a RISC-V timer driver if "timebase-frequency" property is present in the device tree.
Signed-off-by: Bin Meng bmeng.cn@gmail.com ---
drivers/cpu/Kconfig | 6 +++ drivers/cpu/Makefile | 1 + drivers/cpu/riscv_cpu.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 124 insertions(+) create mode 100644 drivers/cpu/riscv_cpu.c
diff --git a/drivers/cpu/Kconfig b/drivers/cpu/Kconfig index d405200..3d5729f 100644 --- a/drivers/cpu/Kconfig +++ b/drivers/cpu/Kconfig @@ -13,3 +13,9 @@ config CPU_MPC83XX select CLK_MPC83XX help Support CPU cores for SoCs of the MPC83xx series. + +config CPU_RISCV + bool "Enable RISC-V CPU driver" + depends on CPU && RISCV + help + Support CPU cores for RISC-V architecture. diff --git a/drivers/cpu/Makefile b/drivers/cpu/Makefile index 858b037..be0300c 100644 --- a/drivers/cpu/Makefile +++ b/drivers/cpu/Makefile @@ -8,4 +8,5 @@ obj-$(CONFIG_CPU) += cpu-uclass.o
obj-$(CONFIG_ARCH_BMIPS) += bmips_cpu.o obj-$(CONFIG_CPU_MPC83XX) += mpc83xx_cpu.o +obj-$(CONFIG_CPU_RISCV) += riscv_cpu.o obj-$(CONFIG_SANDBOX) += cpu_sandbox.o diff --git a/drivers/cpu/riscv_cpu.c b/drivers/cpu/riscv_cpu.c new file mode 100644 index 0000000..23917db --- /dev/null +++ b/drivers/cpu/riscv_cpu.c @@ -0,0 +1,117 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2018, Bin Meng bmeng.cn@gmail.com + */ + +#include <common.h> +#include <cpu.h> +#include <dm.h> +#include <errno.h> +#include <dm/device-internal.h> +#include <dm/lists.h> + +static int riscv_cpu_get_desc(struct udevice *dev, char *buf, int size) +{ + const char *isa; + + isa = dev_read_string(dev, "riscv,isa"); + if (size < (strlen(isa) + 1)) + return -ENOSPC; + + strcpy(buf, isa); + + return 0; +} + +static int riscv_cpu_get_info(struct udevice *dev, struct cpu_info *info) +{ + const char *mmu; + + dev_read_u32(dev, "clock-frequency", (u32 *)&info->cpu_freq); + + mmu = dev_read_string(dev, "mmu-type"); + if (!mmu) + info->features |= BIT(CPU_FEAT_MMU); + + return 0; +} + +static int riscv_cpu_get_count(struct udevice *dev) +{ + ofnode node; + int num = 0; + + ofnode_for_each_subnode(node, dev_ofnode(dev->parent)) { + const char *device_type; + + device_type = ofnode_read_string(node, "device_type"); + if (!device_type) + continue; + if (strcmp(device_type, "cpu") == 0) + num++; + } + + return num; +} + +static int riscv_cpu_bind(struct udevice *dev) +{ + struct cpu_platdata *plat = dev_get_parent_platdata(dev); + struct driver *drv; + struct udevice *timer; + int ret; + + /* save the hart id */ + plat->cpu_id = dev_read_addr(dev); + + /* first examine the property in current cpu node */ + ret = dev_read_u32(dev, "timebase-frequency", &plat->timebase_freq); + /* if not found, then look at the parent /cpus node */ + if (ret) + dev_read_u32(dev->parent, "timebase-frequency", + &plat->timebase_freq); + + /* + * Bind riscv-timer driver on hart 0 + * + * We only instantiate one timer device which is enough for U-Boot. + * Pass the "timebase-frequency" value as the driver data for the + * timer device. + * + * Return value is not checked since it's possible that the timer + * driver is not included. + */ + if (!plat->cpu_id && plat->timebase_freq) { + drv = lists_driver_lookup_name("riscv_timer"); + if (!drv) { + debug("Cannot find the timer driver, not included?\n"); + return 0; + } + + device_bind_with_driver_data(dev, drv, "riscv_timer", + plat->timebase_freq, ofnode_null(), + &timer); + } + + return 0; +} + +static const struct cpu_ops riscv_cpu_ops = { + .get_desc = riscv_cpu_get_desc, + .get_info = riscv_cpu_get_info, + .get_count = riscv_cpu_get_count, +}; + +static const struct udevice_id riscv_cpu_ids[] = { + { .compatible = "riscv" }, + { } +}; + +U_BOOT_DRIVER(riscv_cpu) = { + .name = "riscv_cpu", + .id = UCLASS_CPU, + .of_match = riscv_cpu_ids, + .bind = riscv_cpu_bind, + .ops = &riscv_cpu_ops, + .flags = DM_FLAG_PRE_RELOC, +};