| Submitter | Kevin O'Connor |
|---|---|
| Date | 2010-09-06 15:16:58 |
| Message ID | <20100906151658.GA18582@morn.localdomain> |
| Download | mbox | patch |
| Permalink | /patch/1871/ |
| State | Accepted |
| Commit | r5788 |
| Headers | show |
Comments
Kevin O'Connor wrote: > Code must not access the smbus registers before the RTC power well is > ready (PSON gating). Some boards boot faster than this power well > stabilization, and thus see bad data when accessing the smbus > registers. > --- > src/southbridge/via/vt8237r/vt8237r.h | 1 + > src/southbridge/via/vt8237r/vt8237r_early_smbus.c | 9 +++++++++ > 2 files changed, 10 insertions(+), 0 deletions(-) Hint: use git commit -s to add Signed-off-by: automatically. Acked-by: Peter Stuge <peter@stuge.se>
On Mon, Sep 06, 2010 at 07:25:36PM +0200, Peter Stuge wrote: > Kevin O'Connor wrote: > > Code must not access the smbus registers before the RTC power well is > > ready (PSON gating). Some boards boot faster than this power well > > stabilization, and thus see bad data when accessing the smbus > > registers. > > --- > > src/southbridge/via/vt8237r/vt8237r.h | 1 + > > src/southbridge/via/vt8237r/vt8237r_early_smbus.c | 9 +++++++++ > > 2 files changed, 10 insertions(+), 0 deletions(-) > > Hint: use git commit -s to add Signed-off-by: automatically. Sorry about that: Signed-off-by: Kevin O'Connor <kevin@koconnor.net> > Acked-by: Peter Stuge <peter@stuge.se> Thanks - I don't have commit access so someone will need to check it in. -Kevin
Patch
diff --git a/src/southbridge/via/vt8237r/vt8237r.h b/src/southbridge/via/vt8237r/vt8237r.h index 54a46f8..d54c533 100644 --- a/src/southbridge/via/vt8237r/vt8237r.h +++ b/src/southbridge/via/vt8237r/vt8237r.h @@ -47,6 +47,7 @@ #define IDE_UDMA 0x50 /* SMBus */ +#define VT8237R_PSON 0x82 #define VT8237R_POWER_WELL 0x94 #define VT8237R_SMBUS_IO_BASE_REG 0xd0 #define VT8237R_SMBUS_HOST_CONF 0xd2 diff --git a/src/southbridge/via/vt8237r/vt8237r_early_smbus.c b/src/southbridge/via/vt8237r/vt8237r_early_smbus.c index 357ad81..4372a4a 100644 --- a/src/southbridge/via/vt8237r/vt8237r_early_smbus.c +++ b/src/southbridge/via/vt8237r/vt8237r_early_smbus.c @@ -132,12 +132,15 @@ u8 smbus_read_byte(u8 dimm, u8 offset) return val; } +#define PSONREADY_TIMEOUT 0x7fffffff + /** * Enable the SMBus on VT8237R-based systems. */ void enable_smbus(void) { device_t dev; + int loops; /* Power management controller */ dev = pci_locate_device(PCI_ID(PCI_VENDOR_ID_VIA, @@ -150,6 +153,12 @@ void enable_smbus(void) die("Power management controller not found\n"); } + /* Make sure the RTC power well is up before touching smbus. */ + loops = 0; + while (!(pci_read_config8(dev, VT8237R_PSON) & (1<<6)) + && loops < PSONREADY_TIMEOUT) + ++loops; + /* * 7 = SMBus Clock from RTC 32.768KHz * 5 = Internal PLL reset from susp