Hi Aswin,

Thanks for the driver port.

On Mon, Dec 22, 2025 at 05:18:20PM +0530, Aswin Murugan wrote:
> Added support for Qualcomm RPMH power domain driver, responsible
> for managing power domains on Qualcomm SoCs. This is a port of
> the Linux RPMHPD driver [1] and sa8775p related changes.

> The
> power domain driver currently has support to power on and off
> MMCX power domain of sa8775p;

IIUC, the MMCX power domain relates to multimedia use-cases. Do you have
any such use-case for that in U-Boot? IOW, I don't see a user of the
RPMh functionality you are trying to add in this patch-set.

If it's just meant for now to not have live DT fixups then having just
the stubbed power domains will be sufficient.

-Sumit

> support for other soc entries power
> domains are stubbed, in future, the required soc support can be
> added.
> 
> [1]:
> https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pmdomain/qcom/rpmhpd.c?id=3d25d46a255a83f94d7d4d4216f38aafc8e116b
> 
> Reviewed-by: Neil Armstrong <[email protected]>
> Signed-off-by: Balaji Selvanathan <[email protected]>
> Signed-off-by: Aswin Murugan <[email protected]>
> ---
> v7:
> - No changes to this patch in v7
> 
> v6:
> - Initialized ret with 0 in rpmhpd_probe()
> 
> v5:
> - Changed the first argument passed to rpmh_write as pd->dev
> - Added (ulong) casting in rpmhpd_match_table to address the warning.
> 
> v4:
> - Added all SoC entries from the Linux driver and stubbed it
> - Removed "qcom_rpmhpd" driver
> - Removed unused members in struct rpmhpd
> 
> v3:
> - No changes to this patch in v3
> 
> v2:
> - Added ARCH_SNAPDRAGON dependency to QCOM_POWER_DOMAIN Kconfig
> - In qcom-rpmhpd driver, the un-supported power domains are handled with 
> warning
>   in rpmhpd_power_on() & rpmhpd_power_off()
> ---
>  drivers/power/domain/Kconfig       |   8 +
>  drivers/power/domain/Makefile      |   1 +
>  drivers/power/domain/qcom-rpmhpd.c | 278 +++++++++++++++++++++++++++++
>  3 files changed, 287 insertions(+)
>  create mode 100644 drivers/power/domain/qcom-rpmhpd.c
> 
> diff --git a/drivers/power/domain/Kconfig b/drivers/power/domain/Kconfig
> index 0ad885c9e8b..48e841c638e 100644
> --- a/drivers/power/domain/Kconfig
> +++ b/drivers/power/domain/Kconfig
> @@ -90,6 +90,14 @@ config MESON_SECURE_POWER_DOMAIN
>         Enable support for manipulating Amlogic Meson Secure power domains.
>         Support for Amlogic A1 series.
>  
> +config QCOM_POWER_DOMAIN
> +     bool "Enable the QCOM RPMH Power domain driver"
> +     depends on POWER_DOMAIN && ARCH_SNAPDRAGON
> +     help
> +       Generic RPMH power domain implementation for QCOM devices.
> +       The RPMH power domain driver is responsible for managing power
> +       domains on Qualcomm SoCs.
> +
>  config SANDBOX_POWER_DOMAIN
>       bool "Enable the sandbox power domain test driver"
>       depends on POWER_DOMAIN && SANDBOX
> diff --git a/drivers/power/domain/Makefile b/drivers/power/domain/Makefile
> index 8e03f620437..1c2c64b0964 100644
> --- a/drivers/power/domain/Makefile
> +++ b/drivers/power/domain/Makefile
> @@ -22,3 +22,4 @@ obj-$(CONFIG_TEGRA186_POWER_DOMAIN) += 
> tegra186-power-domain.o
>  obj-$(CONFIG_TI_SCI_POWER_DOMAIN) += ti-sci-power-domain.o
>  obj-$(CONFIG_TI_POWER_DOMAIN) += ti-power-domain.o
>  obj-$(CONFIG_ZYNQMP_POWER_DOMAIN) += zynqmp-power-domain.o
> +obj-$(CONFIG_QCOM_POWER_DOMAIN) += qcom-rpmhpd.o
> diff --git a/drivers/power/domain/qcom-rpmhpd.c 
> b/drivers/power/domain/qcom-rpmhpd.c
> new file mode 100644
> index 00000000000..f51bc9a4bbb
> --- /dev/null
> +++ b/drivers/power/domain/qcom-rpmhpd.c
> @@ -0,0 +1,278 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2018, The Linux Foundation. All rights reserved.
> +// Copyright (c) 2025 Qualcomm Innovation Center, Inc. All rights reserved.
> +
> +#include <dm.h>
> +#include <dm/lists.h>
> +#include <power-domain.h>
> +#include <asm/io.h>
> +#include <linux/errno.h>
> +
> +#include <power-domain-uclass.h>
> +#include <soc/qcom/cmd-db.h>
> +#include <soc/qcom/rpmh.h>
> +#include <dt-bindings/power/qcom-rpmpd.h>
> +#include <dm/device_compat.h>
> +
> +#define RPMH_ARC_MAX_LEVELS  16
> +
> +/**
> + * struct rpmhpd - top level RPMh power domain resource data structure
> + * @dev:                rpmh power domain controller device
> + * @pd:                 generic_pm_domain corresponding to the power domain
> + * @parent:             generic_pm_domain corresponding to the parent's 
> power domain
> + * @enable_corner:      lowest non-zero corner
> + * @level:              An array of level (vlvl) to corner (hlvl) mappings
> + *                      derived from cmd-db
> + * @level_count:        Number of levels supported by the power domain. max
> + *                      being 16 (0 - 15)
> + * @enabled:            true if the power domain is enabled
> + * @res_name:           Resource name used for cmd-db lookup
> + * @addr:               Resource address as looped up using resource name 
> from
> + * @skip_retention_level: Indicate that retention level should not be used 
> for the power domain
> + */
> +struct rpmhpd {
> +     struct udevice  *dev;
> +     struct power_domain pd;
> +     struct power_domain *parent;
> +     unsigned int    enable_corner;
> +     u32             level[RPMH_ARC_MAX_LEVELS];
> +     size_t          level_count;
> +     bool            enabled;
> +     const char      *res_name;
> +     u32             addr;
> +     bool            skip_retention_level;
> +};
> +
> +struct rpmhpd_desc {
> +     struct rpmhpd **rpmhpds;
> +     size_t num_pds;
> +};
> +
> +/* RPMH powerdomains */
> +static struct rpmhpd mmcx_ao;
> +static struct rpmhpd mmcx = {
> +     .res_name = "mmcx.lvl",
> +};
> +
> +static struct rpmhpd mmcx_ao = {
> +     .res_name = "mmcx.lvl",
> +};
> +
> +/* SA8775P RPMH power domains */
> +static struct rpmhpd *sa8775p_rpmhpds[] = {
> +     [SA8775P_MMCX] = &mmcx,
> +     [SA8775P_MMCX_AO] = &mmcx_ao,
> +};
> +
> +static const struct rpmhpd_desc sa8775p_desc = {
> +     .rpmhpds = sa8775p_rpmhpds,
> +     .num_pds = ARRAY_SIZE(sa8775p_rpmhpds),
> +};
> +
> +/* stub RPMH power domains mapped for unsupported platforms */
> +static struct rpmhpd *stub_rpmhpds[] = {};
> +
> +static const struct rpmhpd_desc stub_desc = {
> +     .rpmhpds = stub_rpmhpds,
> +     .num_pds = ARRAY_SIZE(stub_rpmhpds),
> +};
> +
> +static const struct udevice_id rpmhpd_match_table[] = {
> +     { .compatible = "qcom,sa8775p-rpmhpd", .data = (ulong)&sa8775p_desc },
> +     { .compatible = "qcom,qcs615-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,qcs8300-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,qdu1000-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sa8155p-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sa8540p-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sar2130p-rpmhpd", .data = (ulong)&stub_desc},
> +     { .compatible = "qcom,sc7180-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sc7280-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sc8180x-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sc8280xp-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sdm670-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sdm845-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sdx55-rpmhpd", .data = (ulong)&stub_desc},
> +     { .compatible = "qcom,sdx65-rpmhpd", .data = (ulong)&stub_desc},
> +     { .compatible = "qcom,sdx75-rpmhpd", .data = (ulong)&stub_desc},
> +     { .compatible = "qcom,sm4450-rpmhpd", .data = (ulong)&stub_desc},
> +     { .compatible = "qcom,sm6350-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sm7150-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sm8150-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sm8250-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sm8350-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sm8450-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sm8550-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sm8650-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,sm8750-rpmhpd", .data = (ulong)&stub_desc },
> +     { .compatible = "qcom,x1e80100-rpmhpd", .data = (ulong)&stub_desc },
> +     { }
> +};
> +
> +static int rpmhpd_send_corner(struct rpmhpd *pd, int state,
> +                           unsigned int corner, bool sync)
> +{
> +     struct tcs_cmd cmd = {
> +             .addr = pd->addr,
> +             .data = corner,
> +     };
> +
> +     return rpmh_write(pd->dev, state, &cmd, 1);
> +}
> +
> +static int rpmhpd_power_on(struct power_domain *pd)
> +{
> +     int ret;
> +     unsigned int corner;
> +     struct rpmhpd **rpmhpds;
> +     const struct rpmhpd_desc *desc;
> +     struct rpmhpd *curr_rpmhpd;
> +
> +     desc = (const struct rpmhpd_desc *)dev_get_driver_data(pd->dev);
> +     if (!desc)
> +             return -EINVAL;
> +
> +     rpmhpds = desc->rpmhpds;
> +     curr_rpmhpd = rpmhpds[pd->id];
> +
> +     /* Do nothing for undefined power domains */
> +     if (!curr_rpmhpd) {
> +             log_warning("Power domain id (%ld) not supported\n",
> +                         pd->id);
> +             return 0;
> +     }
> +
> +     corner = curr_rpmhpd->enable_corner;
> +
> +     ret = rpmhpd_send_corner(curr_rpmhpd, RPMH_ACTIVE_ONLY_STATE, corner,
> +                              false);
> +     if (!ret)
> +             curr_rpmhpd->enabled = true;
> +
> +     return ret;
> +}
> +
> +static int rpmhpd_power_off(struct power_domain *pd)
> +{
> +     int ret;
> +     unsigned int corner;
> +     struct rpmhpd **rpmhpds;
> +     const struct rpmhpd_desc *desc;
> +     struct rpmhpd *curr_rpmhpd;
> +
> +     desc = (const struct rpmhpd_desc *)dev_get_driver_data(pd->dev);
> +     if (!desc)
> +             return -EINVAL;
> +
> +     rpmhpds = desc->rpmhpds;
> +     curr_rpmhpd = rpmhpds[pd->id];
> +
> +     /* Do nothing for undefined power domains */
> +     if (!curr_rpmhpd) {
> +             log_warning("Power domain id (%ld) not supported\n",
> +                         pd->id);
> +             return 0;
> +     }
> +
> +     corner = 0;
> +
> +     ret = rpmhpd_send_corner(curr_rpmhpd, RPMH_ACTIVE_ONLY_STATE, corner,
> +                              false);
> +     if (!ret)
> +             curr_rpmhpd->enabled = false;
> +
> +     return ret;
> +}
> +
> +static int rpmhpd_update_level_mapping(struct rpmhpd *rpmhpd)
> +{
> +     int i;
> +     const u16 *buf;
> +
> +     buf = cmd_db_read_aux_data(rpmhpd->res_name, &rpmhpd->level_count);
> +     if (IS_ERR(buf))
> +             return PTR_ERR(buf);
> +
> +     /* 2 bytes used for each command DB aux data entry */
> +     rpmhpd->level_count >>= 1;
> +
> +     if (rpmhpd->level_count > RPMH_ARC_MAX_LEVELS)
> +             return -EINVAL;
> +
> +     for (i = 0; i < rpmhpd->level_count; i++) {
> +             if (rpmhpd->skip_retention_level && buf[i] == 
> RPMH_REGULATOR_LEVEL_RETENTION)
> +                     continue;
> +
> +             rpmhpd->level[i] = buf[i];
> +
> +             /* Remember the first corner with non-zero level */
> +             if (!rpmhpd->level[rpmhpd->enable_corner] && rpmhpd->level[i])
> +                     rpmhpd->enable_corner = i;
> +
> +             /*
> +              * The AUX data may be zero padded. These 0 valued entries at
> +              * the end of the map must be ignored.
> +              */
> +             if (i > 0 && rpmhpd->level[i] == 0) {
> +                     rpmhpd->level_count = i;
> +                     break;
> +             }
> +             debug("%s: ARC hlvl=%2d --> vlvl=%4u\n", rpmhpd->res_name, i,
> +                   rpmhpd->level[i]);
> +     }
> +
> +     return 0;
> +}
> +
> +static int rpmhpd_probe(struct udevice *dev)
> +{
> +     int i, ret = 0;
> +     struct rpmhpd **rpmhpds;
> +     struct rpmhpd *priv;
> +     const struct rpmhpd_desc *desc;
> +
> +     desc = (const struct rpmhpd_desc *)dev_get_driver_data(dev);
> +     if (!desc)
> +             return -EINVAL;
> +
> +     rpmhpds = desc->rpmhpds;
> +
> +     for (i = 0; i < desc->num_pds; i++) {
> +             if (!rpmhpds[i])
> +                     continue;
> +
> +             priv = rpmhpds[i];
> +             priv->dev = dev;
> +             priv->addr = cmd_db_read_addr(priv->res_name);
> +             if (!priv->addr) {
> +                     dev_err(dev, "Could not find RPMh address for resource 
> %s\n",
> +                             priv->res_name);
> +                     return -ENODEV;
> +             }
> +
> +             ret = cmd_db_read_slave_id(priv->res_name);
> +             if (ret != CMD_DB_HW_ARC) {
> +                     dev_err(dev, "RPMh slave ID mismatch\n");
> +                     return -EINVAL;
> +             }
> +
> +             ret = rpmhpd_update_level_mapping(priv);
> +             if (ret)
> +                     return ret;
> +     }
> +
> +     return ret;
> +}
> +
> +static const struct power_domain_ops qcom_rpmhpd_power_ops = {
> +     .on = rpmhpd_power_on,
> +     .off = rpmhpd_power_off,
> +};
> +
> +U_BOOT_DRIVER(qcom_rpmhpd_drv) = {
> +     .name = "qcom_rpmhpd_drv",
> +     .id = UCLASS_POWER_DOMAIN,
> +     .of_match = rpmhpd_match_table,
> +     .probe = rpmhpd_probe,
> +     .ops = &qcom_rpmhpd_power_ops,
> +};
> -- 
> 2.34.1
> 

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