Rockbox open source high quality audio player as a Music Player Daemon
mpris
rockbox
mpd
libadwaita
audio
rust
zig
deno
jz4760: Use HW timer for more a more accurate udelay()
(More specifically, use the SoC's "OS Timer", slaved to the main XTAL so
it doesn't matter how the main CPU is clocked)
Change-Id: I799561ac823ff7f659a05144cf03b6a13d57ea7b
+29
+29
firmware/target/mips/ingenic_jz47xx/system-jz4760.c
+29
firmware/target/mips/ingenic_jz47xx/system-jz4760.c
···
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28
#include "kernel.h"
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29
#include "power.h"
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+
#define USE_HW_UDELAY
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+
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static int irq;
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static void UIRQ(void)
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{
···
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panicf("TLB refill handler at 0x%08lx! [0x%x]", read_c0_epc(), read_c0_badvaddr());
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}
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+
#ifdef USE_HW_UDELAY
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/* This enables the HW timer, set to EXT_XTAL / 16 (so @ 12MHz, 1 us = 750 ticks) */
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static void init_delaytimer(void)
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{
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__tcu_disable_ost();
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REG_OST_OSTCSR = OSTCSR_EXT_EN | OSTCSR_PRESCALE16 | OSTCSR_CNT_MD;
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REG_OST_OSTCNT = 0;
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REG_OST_OSTDR = 0;
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__tcu_enable_ost();
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}
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void udelay(unsigned int usec)
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{
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if (!__tcu_ost_enabled())
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init_delaytimer();
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/* Figure out how many ticks we need */
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usec = (CFG_EXTAL / 16 / 1000) * (usec + 1);
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while (usec < REG_OST_OSTCNT) { }
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}
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#else
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void udelay(unsigned int usec)
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{
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unsigned int i = usec * (__cpm_get_cclk() / 2000000);
···
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: "0" (i)
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);
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}
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+
#endif
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void mdelay(unsigned int msec)
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{
···
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/* Disable all interrupts */
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for(i=0; i<IRQ_INTC_MAX; i++)
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dis_irq(i);
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#ifdef USE_HW_UDELAY
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init_delaytimer();
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#endif
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mmu_init();
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