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author | Jan Kiszka <jan.kiszka@siemens.com> | 2011-08-29 17:50:10 +0200 |
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committer | Kevin O'Connor <kevin@koconnor.net> | 2011-09-02 18:04:04 -0400 |
commit | b8a90f513ba83283ee2ac3961d6ce7ae731498d0 (patch) | |
tree | 308ed3ca7fcb00a6f4f6127ec04fd88f85b7437f | |
parent | 83012de1646d2d2156dbe2fe894fd2ca478c7ab5 (diff) | |
download | seabios-b8a90f513ba83283ee2ac3961d6ce7ae731498d0.zip seabios-b8a90f513ba83283ee2ac3961d6ce7ae731498d0.tar.gz seabios-b8a90f513ba83283ee2ac3961d6ce7ae731498d0.tar.bz2 |
Probe HPET existence
QEMU does not provide a HPET block if it was configured with -no-hpet,
other machines SeaBIOS runs on may lack a HPET as well. Perform basic
checks the ID register for a reasonable vendor ID and a clock period
within the valid range, do not build the HPET table if that fails.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
-rw-r--r-- | src/acpi.c | 14 |
1 files changed, 13 insertions, 1 deletions
@@ -158,6 +158,9 @@ struct acpi_20_hpet { } PACKED; #define ACPI_HPET_ADDRESS 0xFED00000UL +#define HPET_ID 0x000 +#define HPET_PERIOD 0x004 + /* * SRAT (NUMA topology description) table */ @@ -464,7 +467,16 @@ build_ssdt(void) static void* build_hpet(void) { - struct acpi_20_hpet *hpet = malloc_high(sizeof(*hpet)); + struct acpi_20_hpet *hpet; + const void *hpet_base = (void *)ACPI_HPET_ADDRESS; + u32 hpet_vendor = readl(hpet_base + HPET_ID) >> 16; + u32 hpet_period = readl(hpet_base + HPET_PERIOD); + + if (hpet_vendor == 0 || hpet_vendor == 0xffff || + hpet_period == 0 || hpet_period > 0x05F5E100) + return NULL; + + hpet = malloc_high(sizeof(*hpet)); if (!hpet) { warn_noalloc(); return NULL; |