commit '8c1b7dc9b: firmware: qcom: scm: Expose download-mode control'
added support for download-mode control using the scm firmware
driver for platforms which require a secure call to write the magic
cookie into the tcsr location.
For platforms which *do not* need an scm call and where the kernel can
write the cookie by a direct read/write, add similar support in the
msm-poweroff driver.
Similar to the scm driver, the msm-poweroff driver clears the cookie
during a clean reboot.
Download mode using msm-poweroff driver can be enabled by including
msm-poweroff.download_mode=1 on the command line.
Signed-off-by: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx>
---
.../bindings/power/reset/msm-poweroff.txt | 3 ++
drivers/power/reset/Kconfig | 11 +++++++
drivers/power/reset/msm-poweroff.c | 38 ++++++++++++++++++++++
3 files changed, 52 insertions(+)
diff --git a/Documentation/devicetree/bindings/power/reset/msm-poweroff.txt b/Documentation/devicetree/bindings/power/reset/msm-poweroff.txt
index ce44ad3..9dd489f 100644
--- a/Documentation/devicetree/bindings/power/reset/msm-poweroff.txt
+++ b/Documentation/devicetree/bindings/power/reset/msm-poweroff.txt
@@ -8,6 +8,9 @@ settings.
Required Properties:
-compatible: "qcom,pshold"
-reg: Specifies the physical address of the ps-hold register
+Optional Properties:
+-qcom,dload-mode: phandle to the TCSR hardware block and offset of the
+ download mode control register
Example:
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index df58fc8..0c97e34 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -104,6 +104,17 @@ config POWER_RESET_MSM
help
Power off and restart support for Qualcomm boards.
+config POWER_RESET_MSM_DOWNLOAD_MODE
+ bool "Qualcomm download mode enabled by default"
+ depends on POWER_RESET_MSM
+ 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 POWER_RESET_OCELOT_RESET
bool "Microsemi Ocelot reset driver"
depends on MSCC_OCELOT || COMPILE_TEST
diff --git a/drivers/power/reset/msm-poweroff.c b/drivers/power/reset/msm-poweroff.c
index 01b8c71..c33eac5 100644
--- a/drivers/power/reset/msm-poweroff.c
+++ b/drivers/power/reset/msm-poweroff.c
@@ -18,11 +18,20 @@
#include <linux/io.h>
#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/reboot.h>
+#include <linux/regmap.h>
#include <linux/pm.h>
+static bool download_mode = IS_ENABLED(CONFIG_POWER_RESET_MSM_DOWNLOAD_MODE);
+module_param(download_mode, bool, 0);
+
+#define QCOM_SET_DLOAD_MODE 0x10
static void __iomem *msm_ps_hold;
+static struct regmap *tcsr_regmap;
+static unsigned int dload_mode_offset;
+
static int deassert_pshold(struct notifier_block *nb, unsigned long action,
void *data)
{
@@ -44,9 +53,30 @@ static void do_msm_poweroff(void)
static int msm_restart_probe(struct platform_device *pdev)
{
+ int ret;
+ struct of_phandle_args args;
struct device *dev = &pdev->dev;
struct resource *mem;
+ if (download_mode) {
+ ret = of_parse_phandle_with_fixed_args(dev->of_node,
+ "qcom,dload-mode", 1, 0,
+ &args);
+ if (ret < 0)
+ return ret;
+
+ tcsr_regmap = syscon_node_to_regmap(args.np);
+ of_node_put(args.np);
+ if (IS_ERR(tcsr_regmap))
+ return PTR_ERR(tcsr_regmap);
+
+ dload_mode_offset = args.args[0];
+
+ /* Enable download mode by writing the cookie */
+ regmap_write(tcsr_regmap, dload_mode_offset,
+ QCOM_SET_DLOAD_MODE);
+ }
+
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
msm_ps_hold = devm_ioremap_resource(dev, mem);
if (IS_ERR(msm_ps_hold))
@@ -59,6 +89,13 @@ static int msm_restart_probe(struct platform_device *pdev)
return 0;
}
+static void msm_restart_shutdown(struct platform_device *pdev)
+{
+ /* Clean shutdown, disable download mode to allow normal restart */
+ if (download_mode)
+ regmap_write(tcsr_regmap, dload_mode_offset, 0x0);
+}
+
static const struct of_device_id of_msm_restart_match[] = {
{ .compatible = "qcom,pshold", },
{},
@@ -71,6 +108,7 @@ static int msm_restart_probe(struct platform_device *pdev)
.name = "msm-restart",
.of_match_table = of_match_ptr(of_msm_restart_match),
},
+ .shutdown = msm_restart_shutdown,
};
static int __init msm_restart_init(void)
--
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of Code Aurora Forum, hosted by The Linux Foundation
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