On 1/25/2023 11:13 PM, Limonciello, Mario wrote: > [Public] > > > >> -----Original Message----- >> From: Shyam Sundar S K <Shyam-sundar.S-k@xxxxxxx> >> Sent: Wednesday, January 25, 2023 05:31 >> To: hdegoede@xxxxxxxxxx; markgross@xxxxxxxxxx >> Cc: Goswami, Sanket <Sanket.Goswami@xxxxxxx>; platform-driver- >> x86@xxxxxxxxxxxxxxx; S-k, Shyam-sundar <Shyam-sundar.S-k@xxxxxxx> >> Subject: [PATCH 2/4] platform/x86/amd: pmc: Write dummy postcode into >> the STB DRAM >> >> Based on the recommendation from the PMFW team in order to get the >> recent telemetry data present on the STB DRAM the driver is required >> to send one dummy write to the STB buffer, so it internally triggers >> the PMFW to emit the latest telemetry data in the STB DRAM region. >> >> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@xxxxxxx> >> --- >> drivers/platform/x86/amd/pmc.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/drivers/platform/x86/amd/pmc.c >> b/drivers/platform/x86/amd/pmc.c >> index 01632e6b7820..0dd9fb576f09 100644 >> --- a/drivers/platform/x86/amd/pmc.c >> +++ b/drivers/platform/x86/amd/pmc.c >> @@ -43,6 +43,7 @@ >> #define AMD_PMC_STB_S2IDLE_PREPARE 0xC6000001 >> #define AMD_PMC_STB_S2IDLE_RESTORE 0xC6000002 >> #define AMD_PMC_STB_S2IDLE_CHECK 0xC6000003 >> +#define AMD_PMC_STB_DUMMY_PC 0xC6000007 > > Is there significance to this specific code? Any particular reason > not to pick an incremental code like 0xC6000004? Wanted to just keep in inline with Windows code atleast w.r.t to this dummy postcode. However, if you think it does not make sense I can change it to incremental one. Thanks, Shyam > >> >> /* STB S2D(Spill to DRAM) has different message port offset */ >> #define STB_SPILL_TO_DRAM 0xBE >> @@ -250,6 +251,11 @@ static int amd_pmc_stb_debugfs_open_v2(struct >> inode *inode, struct file *filp) >> u32 *buf, fsize, num_samples, stb_rdptr_offset = 0; >> int ret; >> >> + /* Write dummy postcode while reading the STB buffer */ >> + ret = amd_pmc_write_stb(dev, AMD_PMC_STB_DUMMY_PC); >> + if (ret) >> + dev_err(dev->dev, "error writing to STB: %d\n", ret); >> + >> buf = kzalloc(S2D_TELEMETRY_BYTES_MAX, GFP_KERNEL); >> if (!buf) >> return -ENOMEM; >> -- >> 2.25.1
