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platform/x86: amd-pmc: Add special handling for timer based S0i3 wakeup

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RTC based wakeup from s0i3 doesn't work properly on some Green Sardine
platforms. Because of this, a newer SMU for Green Sardine has the ability
to pass wakeup time as argument of the upper 16 bits of OS_HINT message.

With older firmware setting the timer value in OS_HINT will cause firmware
to reject the hint, so only run this path on:
1) Green Sardine
2) Minimum SMU FW
3) RTC alarm armed during s0i3 entry

Using this method has some limitations that the s0i3 wakeup will need to
be between 4 seconds and 18 hours, so check those boundary conditions as
well and abort the suspend if RTC is armed for too short or too long of a
duration.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20211020162946.10537-2-mario.limonciello@amd.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Mario Limonciello 2021-10-20 11:29:46 -05:00 committed by Hans de Goede
parent 4c9dbf8622
commit 59348401eb
1 changed files with 59 additions and 1 deletions
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60
drivers/platform/x86/amd-pmc.c
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@ -17,9 +17,11 @@
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/limits.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/suspend.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
@ -412,20 +414,76 @@ static int amd_pmc_get_os_hint(struct amd_pmc_dev *dev)
return -EINVAL;
}
static int amd_pmc_verify_czn_rtc(struct amd_pmc_dev *pdev, u32 *arg)
{
struct rtc_device *rtc_device;
time64_t then, now, duration;
struct rtc_wkalrm alarm;
struct rtc_time tm;
int rc;
if (pdev->major < 64 || (pdev->major == 64 && pdev->minor < 53))
return 0;
rtc_device = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE);
if (!rtc_device)
return 0;
rc = rtc_read_alarm(rtc_device, &alarm);
if (rc)
return rc;
if (!alarm.enabled) {
dev_dbg(pdev->dev, "alarm not enabled\n");
return 0;
}
rc = rtc_valid_tm(&alarm.time);
if (rc)
return rc;
rc = rtc_read_time(rtc_device, &tm);
if (rc)
return rc;
then = rtc_tm_to_time64(&alarm.time);
now = rtc_tm_to_time64(&tm);
duration = then-now;
/* in the past */
if (then < now)
return 0;
/* will be stored in upper 16 bits of s0i3 hint argument,
* so timer wakeup from s0i3 is limited to ~18 hours or less
*/
if (duration <= 4 || duration > U16_MAX)
return -EINVAL;
*arg |= (duration << 16);
rc = rtc_alarm_irq_enable(rtc_device, 0);
dev_info(pdev->dev, "wakeup timer programmed for %lld seconds\n", duration);
return rc;
}
static int __maybe_unused amd_pmc_suspend(struct device *dev)
{
struct amd_pmc_dev *pdev = dev_get_drvdata(dev);
int rc;
u8 msg;
u32 arg = 1;
/* Reset and Start SMU logging - to monitor the s0i3 stats */
amd_pmc_send_cmd(pdev, 0, NULL, SMU_MSG_LOG_RESET, 0);
amd_pmc_send_cmd(pdev, 0, NULL, SMU_MSG_LOG_START, 0);
/* Activate CZN specific RTC functionality */
if (pdev->cpu_id == AMD_CPU_ID_CZN) {
rc = amd_pmc_verify_czn_rtc(pdev, &arg);
if (rc < 0)
return rc;
}
/* Dump the IdleMask before we send hint to SMU */
amd_pmc_idlemask_read(pdev, dev, NULL);
msg = amd_pmc_get_os_hint(pdev);
rc = amd_pmc_send_cmd(pdev, 1, NULL, msg, 0);
rc = amd_pmc_send_cmd(pdev, arg, NULL, msg, 0);
if (rc)
dev_err(pdev->dev, "suspend failed\n");