diff options
Diffstat (limited to 'src/arch')
| -rw-r--r-- | src/arch/arm/include/bits/timer.h | 12 | ||||
| -rw-r--r-- | src/arch/x86/core/rdtsc_timer.c | 157 | ||||
| -rw-r--r-- | src/arch/x86/include/bios.h | 2 | ||||
| -rw-r--r-- | src/arch/x86/include/bits/errfile.h | 1 | ||||
| -rw-r--r-- | src/arch/x86/include/bits/timer.h | 15 | ||||
| -rw-r--r-- | src/arch/x86/include/ipxe/bios_timer.h | 44 | ||||
| -rw-r--r-- | src/arch/x86/include/ipxe/cpuid.h | 6 | ||||
| -rw-r--r-- | src/arch/x86/include/ipxe/rdtsc_timer.h | 39 | ||||
| -rw-r--r-- | src/arch/x86/interface/pcbios/bios_timer.c | 37 |
9 files changed, 157 insertions, 156 deletions
diff --git a/src/arch/arm/include/bits/timer.h b/src/arch/arm/include/bits/timer.h deleted file mode 100644 index 64e7d31d..00000000 --- a/src/arch/arm/include/bits/timer.h +++ /dev/null @@ -1,12 +0,0 @@ -#ifndef _BITS_TIMER_H -#define _BITS_TIMER_H - -/** @file - * - * ARM-specific timer API implementations - * - */ - -FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); - -#endif /* _BITS_TIMER_H */ diff --git a/src/arch/x86/core/rdtsc_timer.c b/src/arch/x86/core/rdtsc_timer.c index e720a239..ed515150 100644 --- a/src/arch/x86/core/rdtsc_timer.c +++ b/src/arch/x86/core/rdtsc_timer.c @@ -29,16 +29,70 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); * */ -#include <assert.h> +#include <string.h> +#include <errno.h> #include <ipxe/timer.h> +#include <ipxe/cpuid.h> #include <ipxe/pit8254.h> +/** Number of microseconds to use for TSC calibration */ +#define TSC_CALIBRATE_US 1024 + +/** TSC increment per microsecond */ +static unsigned long tsc_per_us; + +/** Minimum resolution for scaled TSC timer */ +#define TSC_SCALED_HZ 32 + +/** TSC scale (expressed as a bit shift) + * + * We use this to avoid the need for 64-bit divsion on 32-bit systems. + */ +static unsigned int tsc_scale; + +/** Number of timer ticks per scaled TSC increment */ +static unsigned long ticks_per_scaled_tsc; + +/** Colour for debug messages */ +#define colour &tsc_per_us + +/** + * Get raw TSC value + * + * @ret tsc Raw TSC value + */ +static inline __always_inline unsigned long rdtsc_raw ( void ) { + unsigned long raw; + + __asm__ __volatile__ ( "rdtsc\n\t" : "=a" ( raw ) : : "edx" ); + return raw; +} + +/** + * Get TSC value, shifted to avoid rollover within a realistic timescale + * + * @ret tsc Scaled TSC value + */ +static inline __always_inline unsigned long rdtsc_scaled ( void ) { + unsigned long scaled; + + __asm__ __volatile__ ( "rdtsc\n\t" + "shrdl %b1, %%edx, %%eax\n\t" + : "=a" ( scaled ) : "c" ( tsc_scale ) : "edx" ); + return scaled; +} + /** - * Number of TSC ticks per microsecond + * Get current system time in ticks * - * This is calibrated on the first use of the timer. + * @ret ticks Current time, in ticks */ -static unsigned long rdtsc_ticks_per_usec; +static unsigned long rdtsc_currticks ( void ) { + unsigned long scaled; + + scaled = rdtsc_scaled(); + return ( scaled * ticks_per_scaled_tsc ); +} /** * Delay for a fixed number of microseconds @@ -48,47 +102,76 @@ static unsigned long rdtsc_ticks_per_usec; static void rdtsc_udelay ( unsigned long usecs ) { unsigned long start; unsigned long elapsed; + unsigned long threshold; - /* Sanity guard, since we may divide by this */ - if ( ! usecs ) - usecs = 1; - - start = currticks(); - if ( rdtsc_ticks_per_usec ) { - /* Already calibrated; busy-wait until done */ - do { - elapsed = ( currticks() - start ); - } while ( elapsed < ( usecs * rdtsc_ticks_per_usec ) ); - } else { - /* Not yet calibrated; use 8254 PIT and calibrate - * based on result. - */ - pit8254_udelay ( usecs ); - elapsed = ( currticks() - start ); - rdtsc_ticks_per_usec = ( elapsed / usecs ); - DBG ( "RDTSC timer calibrated: %ld ticks in %ld usecs " - "(%ld MHz)\n", elapsed, usecs, - ( rdtsc_ticks_per_usec << TSC_SHIFT ) ); - } + start = rdtsc_raw(); + threshold = ( usecs * tsc_per_us ); + do { + elapsed = ( rdtsc_raw() - start ); + } while ( elapsed < threshold ); } /** - * Get number of ticks per second + * Probe RDTSC timer * - * @ret ticks_per_sec Number of ticks per second + * @ret rc Return status code */ -static unsigned long rdtsc_ticks_per_sec ( void ) { +static int rdtsc_probe ( void ) { + unsigned long before; + unsigned long after; + unsigned long elapsed; + uint32_t apm; + uint32_t discard_a; + uint32_t discard_b; + uint32_t discard_c; + int rc; - /* Calibrate timer, if not already done */ - if ( ! rdtsc_ticks_per_usec ) - udelay ( 1 ); + /* Check that TSC is invariant */ + if ( ( rc = cpuid_supported ( CPUID_APM ) ) != 0 ) { + DBGC ( colour, "RDTSC cannot determine APM features: %s\n", + strerror ( rc ) ); + return rc; + } + cpuid ( CPUID_APM, &discard_a, &discard_b, &discard_c, &apm ); + if ( ! ( apm & CPUID_APM_EDX_TSC_INVARIANT ) ) { + DBGC ( colour, "RDTSC has non-invariant TSC (%#08x)\n", + apm ); + return -ENOTTY; + } - /* Sanity check */ - assert ( rdtsc_ticks_per_usec != 0 ); + /* Calibrate udelay() timer via 8254 PIT */ + before = rdtsc_raw(); + pit8254_udelay ( TSC_CALIBRATE_US ); + after = rdtsc_raw(); + elapsed = ( after - before ); + tsc_per_us = ( elapsed / TSC_CALIBRATE_US ); + if ( ! tsc_per_us ) { + DBGC ( colour, "RDTSC has zero TSC per microsecond\n" ); + return -EIO; + } + + /* Calibrate currticks() scaling factor */ + tsc_scale = 31; + ticks_per_scaled_tsc = ( ( 1UL << tsc_scale ) / + ( tsc_per_us * ( 1000000 / TICKS_PER_SEC ) ) ); + while ( ticks_per_scaled_tsc > ( TICKS_PER_SEC / TSC_SCALED_HZ ) ) { + tsc_scale--; + ticks_per_scaled_tsc >>= 1; + } + DBGC ( colour, "RDTSC has %ld tsc per us, %ld ticks per 2^%d tsc\n", + tsc_per_us, ticks_per_scaled_tsc, tsc_scale ); + if ( ! ticks_per_scaled_tsc ) { + DBGC ( colour, "RDTSC has zero ticks per TSC\n" ); + return -EIO; + } - return ( rdtsc_ticks_per_usec * 1000 * 1000 ); + return 0; } -PROVIDE_TIMER ( rdtsc, udelay, rdtsc_udelay ); -PROVIDE_TIMER_INLINE ( rdtsc, currticks ); -PROVIDE_TIMER ( rdtsc, ticks_per_sec, rdtsc_ticks_per_sec ); +/** RDTSC timer */ +struct timer rdtsc_timer __timer ( TIMER_PREFERRED ) = { + .name = "rdtsc", + .probe = rdtsc_probe, + .currticks = rdtsc_currticks, + .udelay = rdtsc_udelay, +}; diff --git a/src/arch/x86/include/bios.h b/src/arch/x86/include/bios.h index a5a5d887..14e7acbc 100644 --- a/src/arch/x86/include/bios.h +++ b/src/arch/x86/include/bios.h @@ -7,6 +7,8 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #define BDA_EBDA 0x000e #define BDA_EQUIPMENT_WORD 0x0010 #define BDA_FBMS 0x0013 +#define BDA_TICKS 0x006c +#define BDA_MIDNIGHT 0x0070 #define BDA_REBOOT 0x0072 #define BDA_REBOOT_WARM 0x1234 #define BDA_NUM_DRIVES 0x0075 diff --git a/src/arch/x86/include/bits/errfile.h b/src/arch/x86/include/bits/errfile.h index 105cdf5d..9d1fed7f 100644 --- a/src/arch/x86/include/bits/errfile.h +++ b/src/arch/x86/include/bits/errfile.h @@ -26,6 +26,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #define ERRFILE_rtc_entropy ( ERRFILE_ARCH | ERRFILE_CORE | 0x000f0000 ) #define ERRFILE_acpipwr ( ERRFILE_ARCH | ERRFILE_CORE | 0x00100000 ) #define ERRFILE_cpuid ( ERRFILE_ARCH | ERRFILE_CORE | 0x00110000 ) +#define ERRFILE_rdtsc_timer ( ERRFILE_ARCH | ERRFILE_CORE | 0x00120000 ) #define ERRFILE_bootsector ( ERRFILE_ARCH | ERRFILE_IMAGE | 0x00000000 ) #define ERRFILE_bzimage ( ERRFILE_ARCH | ERRFILE_IMAGE | 0x00010000 ) diff --git a/src/arch/x86/include/bits/timer.h b/src/arch/x86/include/bits/timer.h deleted file mode 100644 index b0ff5ee1..00000000 --- a/src/arch/x86/include/bits/timer.h +++ /dev/null @@ -1,15 +0,0 @@ -#ifndef _BITS_TIMER_H -#define _BITS_TIMER_H - -/** @file - * - * x86-specific timer API implementations - * - */ - -FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); - -#include <ipxe/bios_timer.h> -#include <ipxe/rdtsc_timer.h> - -#endif /* _BITS_TIMER_H */ diff --git a/src/arch/x86/include/ipxe/bios_timer.h b/src/arch/x86/include/ipxe/bios_timer.h deleted file mode 100644 index 6b88a623..00000000 --- a/src/arch/x86/include/ipxe/bios_timer.h +++ /dev/null @@ -1,44 +0,0 @@ -#ifndef _IPXE_BIOS_TIMER_H -#define _IPXE_BIOS_TIMER_H - -/** @file - * - * BIOS timer - * - */ - -FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); - -#ifdef TIMER_PCBIOS -#define TIMER_PREFIX_pcbios -#else -#define TIMER_PREFIX_pcbios __pcbios_ -#endif - -#include <ipxe/pit8254.h> - -/** - * Delay for a fixed number of microseconds - * - * @v usecs Number of microseconds for which to delay - */ -static inline __always_inline void -TIMER_INLINE ( pcbios, udelay ) ( unsigned long usecs ) { - /* BIOS timer is not high-resolution enough for udelay(), so - * we use the 8254 Programmable Interval Timer. - */ - pit8254_udelay ( usecs ); -} - -/** - * Get number of ticks per second - * - * @ret ticks_per_sec Number of ticks per second - */ -static inline __always_inline unsigned long -TIMER_INLINE ( pcbios, ticks_per_sec ) ( void ) { - /* BIOS timer ticks over at 18.2 ticks per second */ - return 18; -} - -#endif /* _IPXE_BIOS_TIMER_H */ diff --git a/src/arch/x86/include/ipxe/cpuid.h b/src/arch/x86/include/ipxe/cpuid.h index 2e2cc7c1..a9df9f0d 100644 --- a/src/arch/x86/include/ipxe/cpuid.h +++ b/src/arch/x86/include/ipxe/cpuid.h @@ -57,6 +57,12 @@ struct x86_features { /** Get CPU model */ #define CPUID_MODEL 0x80000002UL +/** Get APM information */ +#define CPUID_APM 0x80000007UL + +/** Invariant TSC */ +#define CPUID_APM_EDX_TSC_INVARIANT 0x00000100UL + /** * Issue CPUID instruction * diff --git a/src/arch/x86/include/ipxe/rdtsc_timer.h b/src/arch/x86/include/ipxe/rdtsc_timer.h deleted file mode 100644 index 598f4bb0..00000000 --- a/src/arch/x86/include/ipxe/rdtsc_timer.h +++ /dev/null @@ -1,39 +0,0 @@ -#ifndef _IPXE_RDTSC_TIMER_H -#define _IPXE_RDTSC_TIMER_H - -/** @file - * - * RDTSC timer - * - */ - -FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); - -#ifdef TIMER_RDTSC -#define TIMER_PREFIX_rdtsc -#else -#define TIMER_PREFIX_rdtsc __rdtsc_ -#endif - -/** - * RDTSC values can easily overflow an unsigned long. We discard the - * low-order bits in order to obtain sensibly-scaled values. - */ -#define TSC_SHIFT 8 - -/** - * Get current system time in ticks - * - * @ret ticks Current time, in ticks - */ -static inline __always_inline unsigned long -TIMER_INLINE ( rdtsc, currticks ) ( void ) { - unsigned long ticks; - - __asm__ __volatile__ ( "rdtsc\n\t" - "shrdl %1, %%edx, %%eax\n\t" - : "=a" ( ticks ) : "i" ( TSC_SHIFT ) : "edx" ); - return ticks; -} - -#endif /* _IPXE_RDTSC_TIMER_H */ diff --git a/src/arch/x86/interface/pcbios/bios_timer.c b/src/arch/x86/interface/pcbios/bios_timer.c index 3299c9aa..49e1d226 100644 --- a/src/arch/x86/interface/pcbios/bios_timer.c +++ b/src/arch/x86/interface/pcbios/bios_timer.c @@ -32,6 +32,18 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #include <ipxe/timer.h> #include <realmode.h> #include <bios.h> +#include <ipxe/pit8254.h> + +/** Number of ticks per day + * + * This seems to be the normative value, as used by e.g. SeaBIOS to + * decide when to set the midnight rollover flag. + */ +#define BIOS_TICKS_PER_DAY 0x1800b0 + +/** Number of ticks per BIOS tick */ +#define TICKS_PER_BIOS_TICK \ + ( ( TICKS_PER_SEC * 60 * 60 * 24 ) / BIOS_TICKS_PER_DAY ) /** * Get current system time in ticks @@ -43,7 +55,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); * of calling timeofday BIOS interrupt. */ static unsigned long bios_currticks ( void ) { - static int days = 0; + static uint32_t offset; uint32_t ticks; uint8_t midnight; @@ -53,18 +65,25 @@ static unsigned long bios_currticks ( void ) { "nop\n\t" "cli\n\t" ); - get_real ( ticks, BDA_SEG, 0x006c ); - get_real ( midnight, BDA_SEG, 0x0070 ); + /* Read current BIOS time of day */ + get_real ( ticks, BDA_SEG, BDA_TICKS ); + get_real ( midnight, BDA_SEG, BDA_MIDNIGHT ); + /* Handle midnight rollover */ if ( midnight ) { midnight = 0; - put_real ( midnight, BDA_SEG, 0x0070 ); - days += 0x1800b0; + put_real ( midnight, BDA_SEG, BDA_MIDNIGHT ); + offset += BIOS_TICKS_PER_DAY; } + ticks += offset; - return ( days + ticks ); + /* Convert to timer ticks */ + return ( ticks * TICKS_PER_BIOS_TICK ); } -PROVIDE_TIMER_INLINE ( pcbios, udelay ); -PROVIDE_TIMER ( pcbios, currticks, bios_currticks ); -PROVIDE_TIMER_INLINE ( pcbios, ticks_per_sec ); +/** BIOS timer */ +struct timer bios_timer __timer ( TIMER_NORMAL ) = { + .name = "bios", + .currticks = bios_currticks, + .udelay = pit8254_udelay, +}; |