firmware: qcom: scm: Refactor code to support multiple dload mode

Currently on Qualcomm SoC, download_mode is enabled if
CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT is selected or
passed a boolean value from command line.

Refactor the code such that it supports multiple download
modes and drop CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT config
instead, give interface to set the download mode from
module parameter while being backword compatible at the
same time.

Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Link: https://lore.kernel.org/r/20240715155655.1811178-1-quic_mojha@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

diff --git a/drivers/firmware/qcom/Kconfig b/drivers/firmware/qcom/Kconfig
index 73a1a41bf92dddc0bdd58a5bed1e575c5817cb90..b477d54b495a623d568ae3f2e192dd3647484e52 100644 (file)
--- a/drivers/firmware/qcom/Kconfig
+++ b/drivers/firmware/qcom/Kconfig
@@ -41,17 +41,6 @@ config QCOM_TZMEM_MODE_SHMBRIDGE
 
 endchoice
 
-config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
-       bool "Qualcomm download mode enabled by default"
-       depends on QCOM_SCM
-       help
-         A device with "download mode" enabled will upon an unexpected
-         warm-restart enter a special debug mode that allows the user to
-         "download" memory content over USB for offline postmortem analysis.
-         The feature can be enabled/disabled on the kernel command line.
-
-         Say Y here to enable "download mode" by default.
-
 config QCOM_QSEECOM
        bool "Qualcomm QSEECOM interface driver"
        depends on QCOM_SCM=y

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index b1f3258835b17f11db7dcb753bb10d6651904fd5..ca75d1c7006f19f28fd77e2ed5d3cb9b06ed77f0 100644 (file)
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -18,6 +18,7 @@
 #include <linux/init.h>
 #include <linux/interconnect.h>
 #include <linux/interrupt.h>
+#include <linux/kstrtox.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
@@ -32,8 +33,7 @@
 #include "qcom_scm.h"
 #include "qcom_tzmem.h"
 
-static bool download_mode = IS_ENABLED(CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT);
-module_param(download_mode, bool, 0);
+static u32 download_mode;
 
 struct qcom_scm {
        struct device *dev;
@@ -134,6 +134,11 @@ static const char * const qcom_scm_convention_names[] = {
        [SMC_CONVENTION_LEGACY] = "smc legacy",
 };
 
+static const char * const download_mode_name[] = {
+       [QCOM_DLOAD_NODUMP]     = "off",
+       [QCOM_DLOAD_FULLDUMP]   = "full",
+};
+
 static struct qcom_scm *__scm;
 
 static int qcom_scm_clk_enable(void)
@@ -526,17 +531,16 @@ static int qcom_scm_io_rmw(phys_addr_t addr, unsigned int mask, unsigned int val
        return qcom_scm_io_writel(addr, new);
 }
 
-static void qcom_scm_set_download_mode(bool enable)
+static void qcom_scm_set_download_mode(u32 dload_mode)
 {
-       u32 val = enable ? QCOM_DLOAD_FULLDUMP : QCOM_DLOAD_NODUMP;
        int ret = 0;
 
        if (__scm->dload_mode_addr) {
                ret = qcom_scm_io_rmw(__scm->dload_mode_addr, QCOM_DLOAD_MASK,
-                                     FIELD_PREP(QCOM_DLOAD_MASK, val));
+                                     FIELD_PREP(QCOM_DLOAD_MASK, dload_mode));
        } else if (__qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_BOOT,
                                                QCOM_SCM_BOOT_SET_DLOAD_MODE)) {
-               ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
+               ret = __qcom_scm_set_dload_mode(__scm->dev, !!dload_mode);
        } else {
                dev_err(__scm->dev,
                        "No available mechanism for setting download mode\n");
@@ -1887,6 +1891,46 @@ out:
        return IRQ_HANDLED;
 }
 
+static int get_download_mode(char *buffer, const struct kernel_param *kp)
+{
+       if (download_mode >= ARRAY_SIZE(download_mode_name))
+               return sysfs_emit(buffer, "unknown mode\n");
+
+       return sysfs_emit(buffer, "%s\n", download_mode_name[download_mode]);
+}
+
+static int set_download_mode(const char *val, const struct kernel_param *kp)
+{
+       bool tmp;
+       int ret;
+
+       ret = sysfs_match_string(download_mode_name, val);
+       if (ret < 0) {
+               ret = kstrtobool(val, &tmp);
+               if (ret < 0) {
+                       pr_err("qcom_scm: err: %d\n", ret);
+                       return ret;
+               }
+
+               ret = tmp ? 1 : 0;
+       }
+
+       download_mode = ret;
+       if (__scm)
+               qcom_scm_set_download_mode(download_mode);
+
+       return 0;
+}
+
+static const struct kernel_param_ops download_mode_param_ops = {
+       .get = get_download_mode,
+       .set = set_download_mode,
+};
+
+module_param_cb(download_mode, &download_mode_param_ops, NULL, 0644);
+MODULE_PARM_DESC(download_mode,
+               "download mode: off/0/N for no dump mode, full/on/1/Y for full dump mode");
+
 static int qcom_scm_probe(struct platform_device *pdev)
 {
        struct qcom_tzmem_pool_config pool_config;
@@ -1951,7 +1995,7 @@ static int qcom_scm_probe(struct platform_device *pdev)
        __get_convention();
 
        /*
-        * If requested enable "download mode", from this point on warmboot
+        * If "download mode" is requested, from this point on warmboot
         * will cause the boot stages to enter download mode, unless
         * disabled below by a clean shutdown/reboot.
         */
@@ -2002,7 +2046,7 @@ static int qcom_scm_probe(struct platform_device *pdev)
 static void qcom_scm_shutdown(struct platform_device *pdev)
 {
        /* Clean shutdown, disable download mode to allow normal restart */
-       qcom_scm_set_download_mode(false);
+       qcom_scm_set_download_mode(QCOM_DLOAD_NODUMP);
 }
 
 static const struct of_device_id qcom_scm_dt_match[] = {