[PATCH v2 1/2] riscv: Try to get cpu frequency from device tree
Instead of always using the "clock-frequency" property to determine cpu frequency, try using a clock in "clocks" if it exists. This patch also fixes a bug where there could be spurious higher frequencies if sizeof(u32) != sizeof(ulong).
Signed-off-by: Sean Anderson seanga2@gmail.com --- This patch is the combination of the patches https://patchwork.ozlabs.org/patch/1223933/ https://patchwork.ozlabs.org/patch/1224957/ "riscv: Fix incorrect cpu frequency on RV64" "riscv: Try to get cpu frequency from device tree"
Changes for v2: - Renamed err to ret drivers/cpu/riscv_cpu.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/cpu/riscv_cpu.c b/drivers/cpu/riscv_cpu.c index 28ad0aa30f..5309a49e60 100644 --- a/drivers/cpu/riscv_cpu.c +++ b/drivers/cpu/riscv_cpu.c @@ -3,6 +3,7 @@ * Copyright (C) 2018, Bin Meng bmeng.cn@gmail.com */
+#include <clk.h> #include <common.h> #include <cpu.h> #include <dm.h> @@ -27,9 +28,24 @@ static int riscv_cpu_get_desc(struct udevice *dev, char *buf, int size)
static int riscv_cpu_get_info(struct udevice *dev, struct cpu_info *info) { + int ret; + struct clk clk; const char *mmu;
- dev_read_u32(dev, "clock-frequency", (u32 *)&info->cpu_freq); + /* Zero out the frequency, in case sizeof(ulong) != sizeof(u32) */ + info->cpu_freq = 0; + + /* First try getting the frequency from the assigned clock */ + ret = clk_get_by_index(dev, 0, &clk); + if (!ret) { + ret = clk_get_rate(&clk); + if (!IS_ERR_VALUE(ret)) + info->cpu_freq = ret; + clk_free(&clk); + } + + if (!info->cpu_freq) + dev_read_u32(dev, "clock-frequency", (u32 *)&info->cpu_freq);
mmu = dev_read_string(dev, "mmu-type"); if (!mmu)
The cpu clock is probably already enabled if we are executing code (though we could be executing from a different core). This patch prevents the cpu clock or its parents from being disabled.
Signed-off-by: Sean Anderson seanga2@gmail.com --- This doesn't strictly depend on the previous patch, but it doesn't make too much sense without it.
Changes for v2: - New drivers/cpu/riscv_cpu.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
diff --git a/drivers/cpu/riscv_cpu.c b/drivers/cpu/riscv_cpu.c index 5309a49e60..52b74d9e69 100644 --- a/drivers/cpu/riscv_cpu.c +++ b/drivers/cpu/riscv_cpu.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2018, Bin Meng bmeng.cn@gmail.com + * Copyright (C) 2020, Sean Anderson seanga2@gmail.com */
#include <clk.h> @@ -116,6 +117,24 @@ static int riscv_cpu_bind(struct udevice *dev) return 0; }
+static int riscv_cpu_probe(struct udevice *dev) +{ + int ret = 0; + struct clk clk; + + /* Get a clock if it exists */ + ret = clk_get_by_index(dev, 0, &clk); + if (ret) + return 0; + + ret = clk_enable(&clk); + clk_free(&clk); + if (ret == -ENOSYS || ret == -ENOTSUPP) + return 0; + else + return ret; +} + static const struct cpu_ops riscv_cpu_ops = { .get_desc = riscv_cpu_get_desc, .get_info = riscv_cpu_get_info, @@ -132,6 +151,7 @@ U_BOOT_DRIVER(riscv_cpu) = { .id = UCLASS_CPU, .of_match = riscv_cpu_ids, .bind = riscv_cpu_bind, + .probe = riscv_cpu_probe, .ops = &riscv_cpu_ops, .flags = DM_FLAG_PRE_RELOC, };
On Mon, Feb 3, 2020 at 1:40 AM Sean Anderson seanga2@gmail.com wrote:
The cpu clock is probably already enabled if we are executing code (though we could be executing from a different core). This patch prevents the cpu clock or its parents from being disabled.
Signed-off-by: Sean Anderson seanga2@gmail.com
This doesn't strictly depend on the previous patch, but it doesn't make too much sense without it.
Changes for v2: - New drivers/cpu/riscv_cpu.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
Reviewed-by: Bin Meng bmeng.cn@gmail.com
I believe both 2 patches in this series are needed by "riscv: Add Sipeed Maix support" series? If yes, I think you can just put 2 patches into the same series, to give people a good context next time.
Regards, Bin
On Mon, Feb 3, 2020 at 1:38 AM Sean Anderson seanga2@gmail.com wrote:
Instead of always using the "clock-frequency" property to determine cpu frequency, try using a clock in "clocks" if it exists. This patch also fixes a bug where there could be spurious higher frequencies if sizeof(u32) != sizeof(ulong).
Signed-off-by: Sean Anderson seanga2@gmail.com
This patch is the combination of the patches https://patchwork.ozlabs.org/patch/1223933/ https://patchwork.ozlabs.org/patch/1224957/ "riscv: Fix incorrect cpu frequency on RV64" "riscv: Try to get cpu frequency from device tree"
Changes for v2:
- Renamed err to ret
drivers/cpu/riscv_cpu.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-)
Reviewed-by: Bin Meng bmeng.cn@gmail.com
participants (2)
-
Bin Meng -
Sean Anderson