Re: [PATCH 4/8] cpufreq: qcom_cpufreq_nvmem: Simplify reading kryo speedbin

Dmitry Baryshkov
2021-10-14T12:25:14Z

On 14/10/2021 11:32, Yassine Oudjana wrote:
> In preparation for adding a separate device tree for MSM8996 Pro, skip reading
> msm-id from smem and just read the speedbin efuse.

It would be nice to comment, why is it possible/necessary. For example:

MSM8996 Pro has completely different set of frequencies, so it makes no
sense to have a single table covering Pro and original SoCs.
msm8996pro.dtsi would override frequency table from msm8996.dtsi.

>
> Signed-off-by: Yassine Oudjana <y.oudjana@protonmail.com>
> ---
> drivers/cpufreq/Kconfig.arm | 1 -
> drivers/cpufreq/qcom-cpufreq-nvmem.c | 75 +++-------------------------
> 2 files changed, 6 insertions(+), 70 deletions(-)
>
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index 954749afb5fe..7d9798bc5753 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -154,7 +154,6 @@ config ARM_QCOM_CPUFREQ_NVMEM
> tristate "Qualcomm nvmem based CPUFreq"
> depends on ARCH_QCOM
> depends on QCOM_QFPROM
> - depends on QCOM_SMEM
> select PM_OPP
> help
> This adds the CPUFreq driver for Qualcomm Kryo SoC based boards.
> diff --git a/drivers/cpufreq/qcom-cpufreq-nvmem.c b/drivers/cpufreq/qcom-cpufreq-nvmem.c
> index d1744b5d9619..909f7d97b334 100644
> --- a/drivers/cpufreq/qcom-cpufreq-nvmem.c
> +++ b/drivers/cpufreq/qcom-cpufreq-nvmem.c
> @@ -9,8 +9,8 @@
> * based on the silicon variant in use. Qualcomm Process Voltage Scaling Tables
> * defines the voltage and frequency value based on the msm-id in SMEM
> * and speedbin blown in the efuse combination.
> - * The qcom-cpufreq-nvmem driver reads the msm-id and efuse value from the SoC
> - * to provide the OPP framework with required information.
> + * The qcom-cpufreq-nvmem driver reads efuse value from the SoC to provide the
> + * OPP framework with required information.
> * This is used to determine the voltage and frequency value for each OPP of
> * operating-points-v2 table when it is parsed by the OPP framework.
> */
> @@ -27,22 +27,6 @@
> #include <linux/pm_domain.h>
> #include <linux/pm_opp.h>
> #include <linux/slab.h>
> -#include <linux/soc/qcom/smem.h>
> -
> -#define MSM_ID_SMEM 137
> -
> -enum _msm_id {
> - MSM8996V3 = 0xF6ul,
> - APQ8096V3 = 0x123ul,
> - MSM8996SG = 0x131ul,
> - APQ8096SG = 0x138ul,
> -};
> -
> -enum _msm8996_version {
> - MSM8996_V3,
> - MSM8996_SG,
> - NUM_OF_MSM8996_VERSIONS,
> -};
>
> struct qcom_cpufreq_drv;
>
> @@ -142,35 +126,6 @@ static void get_krait_bin_format_b(struct device *cpu_dev,
> dev_dbg(cpu_dev, "PVS version: %d\n", *pvs_ver);
> }
>
> -static enum _msm8996_version qcom_cpufreq_get_msm_id(void)
> -{
> - size_t len;
> - u32 *msm_id;
> - enum _msm8996_version version;
> -
> - msm_id = qcom_smem_get(QCOM_SMEM_HOST_ANY, MSM_ID_SMEM, &len);
> - if (IS_ERR(msm_id))
> - return NUM_OF_MSM8996_VERSIONS;
> -
> - /* The first 4 bytes are format, next to them is the actual msm-id */
> - msm_id++;
> -
> - switch ((enum _msm_id)*msm_id) {
> - case MSM8996V3:
> - case APQ8096V3:
> - version = MSM8996_V3;
> - break;
> - case MSM8996SG:
> - case APQ8096SG:
> - version = MSM8996_SG;
> - break;
> - default:
> - version = NUM_OF_MSM8996_VERSIONS;
> - }
> -
> - return version;
> -}
> -
> static int qcom_cpufreq_kryo_name_version(struct device *cpu_dev,
> struct nvmem_cell *speedbin_nvmem,
> char **pvs_name,
> @@ -178,30 +133,13 @@ static int qcom_cpufreq_kryo_name_version(struct device *cpu_dev,
> {
> size_t len;
> u8 *speedbin;
> - enum _msm8996_version msm8996_version;
> *pvs_name = NULL;
>
> - msm8996_version = qcom_cpufreq_get_msm_id();
> - if (NUM_OF_MSM8996_VERSIONS == msm8996_version) {
> - dev_err(cpu_dev, "Not Snapdragon 820/821!");
> - return -ENODEV;
> - }
> -
> speedbin = nvmem_cell_read(speedbin_nvmem, &len);
> if (IS_ERR(speedbin))
> return PTR_ERR(speedbin);
>
> - switch (msm8996_version) {
> - case MSM8996_V3:
> - drv->versions = 1 << (unsigned int)(*speedbin);
> - break;
> - case MSM8996_SG:
> - drv->versions = 1 << ((unsigned int)(*speedbin) + 4);
> - break;
> - default:
> - BUG();
> - break;
> - }
> + drv->versions = 1 << (unsigned int)(*speedbin);
>
> kfree(speedbin);
> return 0;
> @@ -464,10 +402,9 @@ static const struct of_device_id qcom_cpufreq_match_list[] __initconst = {
> MODULE_DEVICE_TABLE(of, qcom_cpufreq_match_list);
>
> /*
> - * Since the driver depends on smem and nvmem drivers, which may
> - * return EPROBE_DEFER, all the real activity is done in the probe,
> - * which may be defered as well. The init here is only registering
> - * the driver and the platform device.
> + * Since the driver depends on the nvmem driver, which may return EPROBE_DEFER,
> + * all the real activity is done in the probe, which may be defered as well.
> + * The init here is only registering the driver and the platform device.
> */
> static int __init qcom_cpufreq_init(void)
> {
>

--
With best wishes
Dmitry