On Wed, Jul 5, 2017 at 10:33 AM, Rob Lippert <[email protected]> wrote: > I checked the datasheets when I wrote this and ast2400 does not have > the (undocumented) HICRB register bits 14,15 that enables the BMC to > actually respond to the snoop'ed address.
You're right, it is marked as "reserved" in the datasheet for the ast2400. > > Without setting that bit in the ast2500 the transactions to that I/O > port would timeout on the host side (although the BMC snoop logic > would still see it and log it). > Probably not an issue for x86 systems that don't have any LPC I/O > error handling anyways but LPC timeouts causes issues with POWER > systems since it sets a hardware FIR bit which can cause boot > failures. Interesting. I've been running experiments on x86 and I haven't seen any errors, so that adds more credence to your point. If a device doesn't respond within X time, three times in a row, you get a triple fault. But, on x86, I don't think I've seen any mechanism with an expectation that a port IO write will have a guaranteed response. For the use-case I'm chasing, my goal being to snoop PoST codes from the host, there is in the datasheet a post-code control register set, but I haven't explored configuring them or whether someone has written the fifo driver for them. > > -Rob > > On Tue, Jul 4, 2017 at 8:45 AM, Patrick Venture <[email protected]> wrote: >> This driver can be used on the aspeed ast2400. >> >> Tested: ast2400 on quanta-q71l >> >> Signed-off-by: Patrick Venture <[email protected]> >> --- >> drivers/misc/aspeed-lpc-snoop.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/misc/aspeed-lpc-snoop.c >> b/drivers/misc/aspeed-lpc-snoop.c >> index 593905565b74..0647cff6280a 100644 >> --- a/drivers/misc/aspeed-lpc-snoop.c >> +++ b/drivers/misc/aspeed-lpc-snoop.c >> @@ -241,6 +241,7 @@ static int aspeed_lpc_snoop_remove(struct >> platform_device *pdev) >> >> static const struct of_device_id aspeed_lpc_snoop_match[] = { >> { .compatible = "aspeed,ast2500-lpc-snoop" }, >> + { .compatible = "aspeed,ast2400-lpc-snoop" }, >> { }, An approach would be to ditch this change and instead refer to the ast2500-lpc-snoop in my device-tree to avoid anyone non-x86 from running this configuration and hitting issues. >> }; >> >> -- >> 2.13.2.725.g09c95d1e9-goog >>
