[PATCH v4 3/5] sysreset: Implement PSCI based reset to EDL mode for QCOM SoCs

[Casey Connolly]

On 13/06/2025 07:19, Varadarajan Narayanan wrote:
> Implement request_arg() sysreset_op for QCOM SoCs that use
> PSCI to reset to EDL (Emergency Download) mode.
> 
> Signed-off-by: Varadarajan Narayanan <quic_varada at quicinc.com>

Reviewed-by: Casey Connolly <casey.connolly at linaro.org>

> ---
> v4: * Check if ARM_PSCI_1_1_FN64_SYSTEM_RESET2 is supported before
>       issuing it
> 
> v3: * Move argument handling to a separate function and pass the
>       arguments to the actual handler to process
>     * Drop Qcom specific SYSRESET_EDL from the common enum
> 
> v2: * Update commit message
>     * Elaborate Kconfig help text
>     * Use '-edl' instead of 'edl' for consistency with other arguments of reset
>       command
>     * Remove 'weak' for qcom_psci_sysreset_get_status() and make it static
>     * Mention 'SYSRESET_EDL' is Qcom specific in the enum's comments
> ---
>  drivers/firmware/psci.c               |  4 +++
>  drivers/sysreset/Kconfig              |  6 ++++
>  drivers/sysreset/Makefile             |  1 +
>  drivers/sysreset/sysreset_qcom-psci.c | 45 +++++++++++++++++++++++++++
>  4 files changed, 56 insertions(+)
>  create mode 100644 drivers/sysreset/sysreset_qcom-psci.c
> 
> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> index 2e3223e1c32..b6838a244d2 100644
> --- a/drivers/firmware/psci.c
> +++ b/drivers/firmware/psci.c
> @@ -186,6 +186,10 @@ static int psci_bind(struct udevice *dev)
>  					 NULL);
>  		if (ret)
>  			pr_debug("PSCI System Reset was not bound.\n");
> +		if (IS_ENABLED(CONFIG_SYSRESET_QCOM_PSCI) &&
> +		    device_bind_driver(dev, "qcom_psci-sysreset",
> +				       "qcom_psci-sysreset", NULL))
> +			pr_debug("QCOM PSCI System Reset was not bound.\n");
>  	}
>  
>  	/* From PSCI v1.0 onward we can discover services through ARM_SMCCC_FEATURE */
> diff --git a/drivers/sysreset/Kconfig b/drivers/sysreset/Kconfig
> index aa83073c96a..894c3d38b26 100644
> --- a/drivers/sysreset/Kconfig
> +++ b/drivers/sysreset/Kconfig
> @@ -292,6 +292,12 @@ config SYSRESET_RAA215300
>  	help
>  	  Add support for the system reboot via the Renesas RAA215300 PMIC.
>  
> +config SYSRESET_QCOM_PSCI
> +	bool "Support reset to EDL for Qualcomm SoCs via PSCI"
> +	help
> +	  Add support for the reset to EDL (Emergency Download) on Qualcomm
> +	  SoCs via PSCI.
> +
>  config SYSRESET_QCOM_PSHOLD
>  	bool "Support sysreset for Qualcomm SoCs via PSHOLD"
>  	help
> diff --git a/drivers/sysreset/Makefile b/drivers/sysreset/Makefile
> index f5c78b25896..8bb1eabd48e 100644
> --- a/drivers/sysreset/Makefile
> +++ b/drivers/sysreset/Makefile
> @@ -30,5 +30,6 @@ obj-$(CONFIG_SYSRESET_RESETCTL) += sysreset_resetctl.o
>  obj-$(CONFIG_$(PHASE_)SYSRESET_AT91) += sysreset_at91.o
>  obj-$(CONFIG_$(PHASE_)SYSRESET_X86) += sysreset_x86.o
>  obj-$(CONFIG_SYSRESET_RAA215300) += sysreset_raa215300.o
> +obj-$(CONFIG_SYSRESET_QCOM_PSCI) += sysreset_qcom-psci.o
>  obj-$(CONFIG_SYSRESET_QCOM_PSHOLD) += sysreset_qcom-pshold.o
>  obj-$(CONFIG_TARGET_XTFPGA) += sysreset_xtfpga.o
> diff --git a/drivers/sysreset/sysreset_qcom-psci.c b/drivers/sysreset/sysreset_qcom-psci.c
> new file mode 100644
> index 00000000000..3627bbf5c82
> --- /dev/null
> +++ b/drivers/sysreset/sysreset_qcom-psci.c
> @@ -0,0 +1,45 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2017 Masahiro Yamada <yamada.masahiro at socionext.com>
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#include <dm.h>
> +#include <sysreset.h>
> +#include <asm/system.h>
> +#include <linux/errno.h>
> +#include <linux/psci.h>
> +#include <asm/psci.h>
> +
> +static int qcom_psci_sysreset_get_status(struct udevice *dev, char *buf, int size)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static int qcom_psci_sysreset_request_arg(struct udevice *dev, int argc,
> +					  char * const argv[])
> +{
> +	if (!strncasecmp(argv[1], "-edl", 4)) {
> +		/* Supported in qcs9100, qcs8300, sc7280, qcs615 */
> +		if (psci_features(ARM_PSCI_1_1_FN64_SYSTEM_RESET2) ==
> +							ARM_PSCI_RET_SUCCESS) {
> +			psci_system_reset2(0, 1);
> +			return -EINPROGRESS;
> +		}
> +		printf("PSCI SYSTEM_RESET2 not supported\n");
> +	}
> +
> +	return -EPROTONOSUPPORT;
> +}
> +
> +static struct sysreset_ops qcom_psci_sysreset_ops = {
> +	.request_arg = qcom_psci_sysreset_request_arg,
> +	.get_status = qcom_psci_sysreset_get_status,
> +};
> +
> +U_BOOT_DRIVER(qcom_psci_sysreset) = {
> +	.name = "qcom_psci-sysreset",
> +	.id = UCLASS_SYSRESET,
> +	.ops = &qcom_psci_sysreset_ops,
> +	.flags = DM_FLAG_PRE_RELOC,
> +};

-- 
// Casey (she/her)