*** Disclaimer: I know extremely little about Qualcomm's undocumented SMC API. ***
I'm trying to get upstream support for an IPQ4019 device I have, and by default, warm boot does not work properly -- it appears to trap into TrustZone. I find that the downstream/vendor kernel makes this call at boot, with notes about the watchdog and SDI configuration. It appears some of this is leftover from when they had download-mode enabled, as well as some other debug features, and they didn't get completely turned off in the production bootloader. But I reall can't tell that well; I'm just going off the minimal source code and git logs. Because this is so undocumented, I can't tell what the right thing to do is -- should this go behind a DT property? Should I apply it only for ipq4019? Is there a better way to describe and document the bits used in this command? If it helps, I can try to shop around for some testing on other systems. Signed-off-by: Brian Norris <[email protected]> --- drivers/firmware/qcom_scm.c | 20 ++++++++++++++++++++ drivers/firmware/qcom_scm.h | 1 + 2 files changed, 21 insertions(+) diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c index 0e7233a20f34..70c46f1668d1 100644 --- a/drivers/firmware/qcom_scm.c +++ b/drivers/firmware/qcom_scm.c @@ -394,6 +394,20 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable) return qcom_scm_call(__scm->dev, &desc, NULL); } +static int __qcom_scm_disable_sdi(struct device *dev) +{ + struct qcom_scm_desc desc = { + .svc = QCOM_SCM_SVC_BOOT, + .cmd = QCOM_SCM_BOOT_CONFIG_SDI, + .arginfo = QCOM_SCM_ARGS(2), + .args[0] = 1 /* 1: disable watchdog debug */, + .args[1] = 0 /* 0: disable SDI */, + .owner = ARM_SMCCC_OWNER_SIP, + }; + + return qcom_scm_call(__scm->dev, &desc, NULL); +} + static void qcom_scm_set_download_mode(bool enable) { bool avail; @@ -1122,6 +1136,12 @@ static int qcom_scm_probe(struct platform_device *pdev) if (download_mode) qcom_scm_set_download_mode(true); + /* + * Some bootloaders leave this enabled by default, which prevents + * normal warm reboot. + */ + __qcom_scm_disable_sdi(__scm->dev); + return 0; } diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h index d9ed670da222..39c3dc0dfc50 100644 --- a/drivers/firmware/qcom_scm.h +++ b/drivers/firmware/qcom_scm.h @@ -74,6 +74,7 @@ extern int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc, #define QCOM_SCM_SVC_BOOT 0x01 #define QCOM_SCM_BOOT_SET_ADDR 0x01 #define QCOM_SCM_BOOT_TERMINATE_PC 0x02 +#define QCOM_SCM_BOOT_CONFIG_SDI 0x09 #define QCOM_SCM_BOOT_SET_DLOAD_MODE 0x10 #define QCOM_SCM_BOOT_SET_REMOTE_STATE 0x0a #define QCOM_SCM_FLUSH_FLAG_MASK 0x3 -- 2.27.0
