Aaron Durbin (adurbin@chromium.org) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13671
-gerrit
commit ca45f68f36b83b23e5a0f0db014ecafc1e8381aa Author: Aaron Durbin adurbin@chromium.org Date: Wed Feb 10 11:01:49 2016 -0600
libpayload: honor TSC information under CONFIG_LP_TIMER_RDTSC
When CONFIG_LP_TIMER_RDTSC is enabled honor the TSC information exported in the coreboot tables as the cpu_khz frequency. That allows get_cpu_speed() not to be called which currently relies on the 8254 PIT. As certain x86 platforms allow that device to be optional or turned off for power saving reasons, allow a path where get_cpu_speed() is no longer called. Additionally, this approach also allows the libpayload to not duplicate logic that already exists in coreboot.
BUG=chrome-os-partner:50214 BRANCH=glados TEST=Confirmed in payload TSC frequency is honored instead of using get_cpu_speed().
Change-Id: Ib8993afdfb49065d43de705d6dbbdb9174b6f2c4 Signed-off-by: Aaron Durbin adurbin@chromium.org --- payloads/libpayload/arch/x86/sysinfo.c | 11 +++++++---- payloads/libpayload/include/coreboot_tables.h | 8 ++++++++ payloads/libpayload/libc/coreboot.c | 18 ++++++++++++++++++ 3 files changed, 33 insertions(+), 4 deletions(-)
diff --git a/payloads/libpayload/arch/x86/sysinfo.c b/payloads/libpayload/arch/x86/sysinfo.c index c3336b8..ddd6550 100644 --- a/payloads/libpayload/arch/x86/sysinfo.c +++ b/payloads/libpayload/arch/x86/sysinfo.c @@ -32,12 +32,14 @@ #include <coreboot_tables.h> #include <multiboot_tables.h>
+#define CPU_KHZ_DEFAULT 200 + /** * This is a global structure that is used through the library - we set it * up initially with some dummy values - hopefully they will be overridden. */ struct sysinfo_t lib_sysinfo = { - .cpu_khz = 200, + .cpu_khz = CPU_KHZ_DEFAULT, #if IS_ENABLED(CONFIG_LP_SERIAL_CONSOLE) .ser_ioport = CONFIG_LP_SERIAL_IOBASE, #else @@ -49,9 +51,6 @@ int lib_get_sysinfo(void) { int ret;
- /* Get the CPU speed (for delays). */ - lib_sysinfo.cpu_khz = get_cpu_speed(); - #if IS_ENABLED(CONFIG_LP_MULTIBOOT) /* Get the information from the multiboot tables, * if they exist */ @@ -63,6 +62,10 @@ int lib_get_sysinfo(void)
ret = get_coreboot_info(&lib_sysinfo);
+ /* Get the CPU speed (for delays) if not set from the default value. */ + if (lib_sysinfo.cpu_khz == CPU_KHZ_DEFAULT) + lib_sysinfo.cpu_khz = get_cpu_speed(); + if (!lib_sysinfo.n_memranges) { /* If we can't get a good memory range, use the default. */ lib_sysinfo.n_memranges = 2; diff --git a/payloads/libpayload/include/coreboot_tables.h b/payloads/libpayload/include/coreboot_tables.h index 24cbf45..276f25f 100644 --- a/payloads/libpayload/include/coreboot_tables.h +++ b/payloads/libpayload/include/coreboot_tables.h @@ -268,6 +268,14 @@ struct cb_boot_media_params { uint64_t boot_media_size; };
+#define CB_TAG_TSC_INFO 0x0032 +struct cb_tsc_info { + uint32_t tag; + uint32_t size; + + uint32_t freq_khz; +}; + #define CB_TAG_SERIALNO 0x002a #define CB_MAX_SERIALNO_LENGTH 32
diff --git a/payloads/libpayload/libc/coreboot.c b/payloads/libpayload/libc/coreboot.c index 3e248e1..3abd610 100644 --- a/payloads/libpayload/libc/coreboot.c +++ b/payloads/libpayload/libc/coreboot.c @@ -231,6 +231,19 @@ static void cb_parse_boot_media_params(unsigned char *ptr, info->boot_media_size = bmp->boot_media_size; }
+#if IS_ENABLED(CONFIG_LP_TIMER_RDTSC) +static void cb_parse_tsc_info(void *ptr, struct sysinfo_t *info) +{ + const struct cb_tsc_info *tsc_info = ptr; + + if (tsc_info->freq_khz == 0) + return; + + /* Honor the TSC frequency passed to the payload. */ + info->cpu_khz = tsc_info->freq_khz; +} +#endif + int cb_parse_header(void *addr, int len, struct sysinfo_t *info) { struct cb_header *header; @@ -386,6 +399,11 @@ int cb_parse_header(void *addr, int len, struct sysinfo_t *info) case CB_TAG_BOOT_MEDIA_PARAMS: cb_parse_boot_media_params(ptr, info); break; +#if IS_ENABLED(CONFIG_LP_TIMER_RDTSC) + case CB_TAG_TSC_INFO: + cb_parse_tsc_info(ptr, info); + break; +#endif default: cb_parse_arch_specific(rec, info); break;