| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <ebd4790b-e7aa-45b1-b7d7-9d1b331ee842@nxsw.ie>
Date: Thu, 01 May 2025 00:01:21 +0000
From: Bryan O'Donoghue <bod.linux@...w.ie>
To: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@....qualcomm.com>, Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Bjorn Andersson <andersson@...nel.org>, Konrad Dybcio <konradybcio@...nel.org>, Wim Van Sebroeck <wim@...ux-watchdog.org>, Guenter Roeck <linux@...ck-us.net>, Rajendra Nayak <quic_rjendra@...cinc.com>
Cc: linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org
Subject: Re: [PATCH v2 5/5] watchdog: qcom: add support to read the restart reason from IMEM
On 16/04/2025 09:29, Kathiravan Thirumoorthy wrote:
> When the system boots up after a watchdog reset, the EXPIRED_STATUS bit
> in the WDT_STS register is cleared. To identify if the system was restarted
> due to WDT expiry, bootloaders update the information in the IMEM region.
> Update the driver to read the restart reason from IMEM and populate the
> bootstatus accordingly.
Which bootloaders ?
Do you mean bootrom or one of the subsequent phase bootloaders ?
Please be specific about which bootloader populates this data i.e. if I
switch my bootloader to u-boot do I loose the added flag ?
> For backward compatibility, keep the EXPIRED_STATUS bit check. Add a new
> function qcom_wdt_get_restart_reason() to read the restart reason from
> IMEM.
>
> Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@....qualcomm.com>
What I'd really love to see here is an example of reading out the data
from sysfs.
How do I as a user/consumer of this new functionality parse the new data
it provides ?
Ideally do this in the commit log and recommend doing it in the cover
letter to, as people don't always read both when commenting on patches.
> ---
> Changes in v2:
> - Use the syscon API to access the IMEM region
> - Handle the error cases returned by qcom_wdt_get_restart_reason
> - Define device specific data to retrieve the IMEM compatible,
> offset and the value for non secure WDT, which allows to
> extend the support for other SoCs
> ---
> drivers/watchdog/qcom-wdt.c | 47 +++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 45 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
> index 006f9c61aa64fd2b4ee9db493aeb54c8fafac818..94ba9ec9907a19854cd45a94f8da17d6e6eb33bc 100644
> --- a/drivers/watchdog/qcom-wdt.c
> +++ b/drivers/watchdog/qcom-wdt.c
> @@ -7,9 +7,11 @@
> #include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/kernel.h>
> +#include <linux/mfd/syscon.h>
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/platform_device.h>
> +#include <linux/regmap.h>
> #include <linux/watchdog.h>
>
> enum wdt_reg {
> @@ -39,6 +41,9 @@ static const u32 reg_offset_data_kpss[] = {
> };
>
> struct qcom_wdt_match_data {
> + const char *compatible;
> + unsigned int restart_reason_offset;
> + unsigned int non_secure_wdt_val;
> const u32 *offset;
> bool pretimeout;
> u32 max_tick_count;
> @@ -175,6 +180,15 @@ static const struct watchdog_info qcom_wdt_pt_info = {
> .identity = KBUILD_MODNAME,
> };
>
> +static const struct qcom_wdt_match_data match_data_ipq5424 = {
> + .compatible = "qcom,ipq5424-imem",
> + .restart_reason_offset = 0x7b0,
> + .non_secure_wdt_val = 0x5,
> + .offset = reg_offset_data_kpss,
> + .pretimeout = true,
> + .max_tick_count = 0xFFFFFU,
> +};
> +
You should separate the addition of your compatibles and their
descriptor tables from generic functional extensions.
i.e. add the compat string and the above table in a subsequent patch.
> static const struct qcom_wdt_match_data match_data_apcs_tmr = {
> .offset = reg_offset_data_apcs_tmr,
> .pretimeout = false,
> @@ -187,6 +201,29 @@ static const struct qcom_wdt_match_data match_data_kpss = {
> .max_tick_count = 0xFFFFFU,
> };
>
> +static int qcom_wdt_get_restart_reason(struct qcom_wdt *wdt,
> + const struct qcom_wdt_match_data *data)
> +{
> + struct regmap *imem;
> + unsigned int val;
> + int ret;
> +
> + imem = syscon_regmap_lookup_by_compatible(data->compatible);
> + if (IS_ERR(imem))
> + return PTR_ERR(imem);
> +
> + ret = regmap_read(imem, data->restart_reason_offset, &val);
> + if (ret) {
> + dev_err(wdt->wdd.parent, "failed to read the restart reason info\n");
> + return ret;
> + }
> +
> + if (val == data->non_secure_wdt_val)
> + wdt->wdd.bootstatus = WDIOF_CARDRESET;
> +
> + return 0;
> +}
> +
> static int qcom_wdt_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -267,8 +304,13 @@ static int qcom_wdt_probe(struct platform_device *pdev)
> wdt->wdd.parent = dev;
> wdt->layout = data->offset;
>
> - if (readl(wdt_addr(wdt, WDT_STS)) & 1)
> - wdt->wdd.bootstatus = WDIOF_CARDRESET;
> + ret = qcom_wdt_get_restart_reason(wdt, data);
> + if (ret == -ENODEV) {
> + if (readl(wdt_addr(wdt, WDT_STS)) & 1)
> + wdt->wdd.bootstatus = WDIOF_CARDRESET;
> + } else if (ret) {
> + return ret;
> + }
>
> /*
> * If 'timeout-sec' unspecified in devicetree, assume a 30 second
> @@ -322,6 +364,7 @@ static const struct dev_pm_ops qcom_wdt_pm_ops = {
> };
>
> static const struct of_device_id qcom_wdt_of_table[] = {
> + { .compatible = "qcom,apss-wdt-ipq5424", .data = &match_data_ipq5424 },
> { .compatible = "qcom,kpss-timer", .data = &match_data_apcs_tmr },
> { .compatible = "qcom,scss-timer", .data = &match_data_apcs_tmr },
> { .compatible = "qcom,kpss-wdt", .data = &match_data_kpss },
>
> --
> 2.34.1
>
>
Powered by blists - more mailing lists