From 1383920fef40f9ee7b1dd7e9f019ba67c77f2d58 Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Mon, 20 Jul 2015 14:28:01 -0500 Subject: skylake: provide more clarity for PCR access The current primary to sideband (P2SB) code for private configuration register (PCR) access weren't very clear with the naming or reasoning for some of the code. Provide more verbiage surrounding this interface. BUG=None BRANCH=None TEST=Built and booted glados. Change-Id: I5b2e84444a29b2fc2f527502e8c9f26eb60e687a Signed-off-by: Patrick Georgi Original-Commit-Id: 06345ba1abd893059a6584856851f92f43289247 Original-Change-Id: If57a4bbc90365c1135b4986dce328b5dbabe483b Original-Signed-off-by: Aaron Durbin Original-Reviewed-on: https://chromium-review.googlesource.com/286900 Original-Reviewed-by: Duncan Laurie Reviewed-on: http://review.coreboot.org/11029 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin --- src/soc/intel/skylake/include/soc/pcr.h | 5 ++++- src/soc/intel/skylake/pcr.c | 16 +++++++++++++++- 2 files changed, 19 insertions(+), 2 deletions(-) (limited to 'src') diff --git a/src/soc/intel/skylake/include/soc/pcr.h b/src/soc/intel/skylake/include/soc/pcr.h index 9ac9eddd48..a6987cb33a 100644 --- a/src/soc/intel/skylake/include/soc/pcr.h +++ b/src/soc/intel/skylake/include/soc/pcr.h @@ -16,9 +16,12 @@ #ifndef _SOC_PCR_H_ #define _SOC_PCR_H_ +/* + * Primary to sideband (P2SB) for private configuration registers (PCR). + */ + /* PCH (SunRisePoint LP) */ #define PCH_PCR_BASE_ADDRESS 0xFD000000 -#define R_PCH_PCR_LPC_GCFD 0x3418 /* DMI Control Register */ #define R_PCH_PCR_DMI_DMIC 0x2234 diff --git a/src/soc/intel/skylake/pcr.c b/src/soc/intel/skylake/pcr.c index 33d6cd12f5..79c32f90a7 100644 --- a/src/soc/intel/skylake/pcr.c +++ b/src/soc/intel/skylake/pcr.c @@ -69,6 +69,19 @@ u8 pcr_read8(PCH_SBI_PID pid, u16 offset, u8 *outdata) return pch_pcr_read(pid, offset, sizeof(u8), (u32 *)outdata); } +/* + * After every write one needs to perform a read an innocuous register to + * ensure the writes are completed for certain ports. This is done for + * all ports so that the callers don't need the per-port knowledge for + * each transaction. + */ +static inline void complete_write(void) +{ + /* Read the general control and function disable register. */ + const size_t R_PCH_PCR_LPC_GCFD = 0x3418; + read32(PCH_PCR_ADDRESS(PID_LPC, R_PCH_PCR_LPC_GCFD)); +} + /* * Write PCR register. (This is internal function) * It returns PCR register and size in 1/2/4 bytes. @@ -101,7 +114,8 @@ static u8 pch_pcr_write(PCH_SBI_PID pid, u16 offset, u32 size, u32 data) default: break; } - read32(PCH_PCR_ADDRESS(PID_LPC, R_PCH_PCR_LPC_GCFD)); + /* Ensure the writes complete. */ + complete_write(); return 0; } -- cgit v1.2.3