111 lines
2.2 KiB
C
111 lines
2.2 KiB
C
/*
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* Copyright (C) 2017 Jean-Christophe PLAGNIOL-VILLARD <plagnio@jcrosoft.com>
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*
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* Under GPL v2
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*/
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#include <common.h>
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#include <init.h>
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#include <driver.h>
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#include <clock.h>
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#include <efi.h>
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#include <efi/efi.h>
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#include <efi/efi-device.h>
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#include <linux/err.h>
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static uint64_t ticks = 1;
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static void *efi_cs_evt;
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static uint64_t efi_cs_read(void)
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{
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return ticks;
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}
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static void efi_cs_inc(void *event, void *ctx)
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{
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ticks++;
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}
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/* count ticks during a 1dms */
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static uint64_t ticks_freq(void)
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{
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uint64_t ticks_start, ticks_end;
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ticks_start = ticks;
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BS->stall(1000);
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ticks_end = ticks;
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return (ticks_end - ticks_start) * 1000;
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}
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/* count ticks during a 20ms delay as on qemu x86_64 the max is 100Hz */
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static uint64_t ticks_freq_x86(void)
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{
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uint64_t ticks_start, ticks_end;
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ticks_start = ticks;
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BS->stall(20 * 1000);
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ticks_end = ticks;
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return (ticks_end - ticks_start) * 50;
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}
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static int efi_cs_init(struct clocksource *cs)
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{
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efi_status_t efiret;
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uint64_t freq;
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efiret = BS->create_event(EFI_EVT_TIMER | EFI_EVT_NOTIFY_SIGNAL,
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EFI_TPL_CALLBACK, efi_cs_inc, NULL, &efi_cs_evt);
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if (EFI_ERROR(efiret))
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return -efi_errno(efiret);
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efiret = BS->set_timer(efi_cs_evt, EFI_TIMER_PERIODIC, 10);
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if (EFI_ERROR(efiret)) {
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BS->close_event(efi_cs_evt);
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return -efi_errno(efiret);
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}
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freq = 1000 * 1000;
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if (ticks_freq() < 800 * 1000) {
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uint64_t nb_100ns;
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freq = ticks_freq_x86();
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nb_100ns = 10 * 1000 * 1000 / freq;
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pr_warn("EFI Event timer too slow freq = %llu Hz\n", freq);
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efiret = BS->set_timer(efi_cs_evt, EFI_TIMER_PERIODIC, nb_100ns);
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if (EFI_ERROR(efiret)) {
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BS->close_event(efi_cs_evt);
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return -efi_errno(efiret);
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}
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}
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cs->mult = clocksource_hz2mult(freq, cs->shift);
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return 0;
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}
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static struct clocksource efi_cs = {
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.read = efi_cs_read,
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.mask = CLOCKSOURCE_MASK(64),
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.shift = 0,
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.init = efi_cs_init,
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};
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static int efi_cs_probe(struct device_d *dev)
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{
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return init_clock(&efi_cs);
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}
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static struct driver_d efi_cs_driver = {
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.name = "efi-cs",
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.probe = efi_cs_probe,
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};
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static int efi_cs_initcall(void)
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{
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return platform_driver_register(&efi_cs_driver);
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}
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/* for efi the time must be init at core initcall level */
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core_initcall(efi_cs_initcall);
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