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jz4760: Fix and re-enable the hardware udelay() timer 

Change-Id: I591b4f023776b3501fce03e08bfc87a355f4c69b
This commit is contained in:
Solomon Peachy 2020-09-05 20:16:17 -04:00
parent 2dadb8c7d6
commit 53142ae9f5
1 changed files with 19 additions and 12 deletions
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31
firmware/target/mips/ingenic_jz47xx/system-jz4760.c
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@ -28,7 +28,7 @@
#include "kernel.h"
#include "power.h"
//#define USE_HW_UDELAY // This is BROKEN.
#define HW_UDELAY_TIMER 3
#ifdef BOOTLOADER
#define WITH_SERIAL
#endif
@ -341,28 +341,35 @@ void tlb_refill_handler(void)
panicf("TLB refill handler at 0x%08lx! [0x%x]", read_c0_epc(), read_c0_badvaddr());
}
#ifdef USE_HW_UDELAY
#ifdef HW_UDELAY_TIMER
/* This enables the HW timer, set to EXT_XTAL / 4 (so @ 12/4 = 3MHz, 1 us = 3 ticks) */
static void init_delaytimer(void)
{
__tcu_disable_ost();
REG_OST_OSTCSR = OSTCSR_EXT_EN | OSTCSR_PRESCALE4 | OSTCSR_CNT_MD;
REG_OST_OSTCNT = 0;
REG_OST_OSTDR = 0;
__tcu_enable_ost();
__tcu_stop_counter(HW_UDELAY_TIMER);
__tcu_disable_pwm_output(HW_UDELAY_TIMER);
__tcu_select_extalclk(HW_UDELAY_TIMER);
__tcu_clear_half_match_flag(HW_UDELAY_TIMER);
__tcu_clear_full_match_flag(HW_UDELAY_TIMER);
__tcu_mask_half_match_irq(HW_UDELAY_TIMER);
__tcu_mask_full_match_irq(HW_UDELAY_TIMER);
__tcu_select_clk_div4(HW_UDELAY_TIMER);
REG_TCU_TCNT(HW_UDELAY_TIMER) = 0;
REG_TCU_TDFR(HW_UDELAY_TIMER) = 0xffff; /* wraps at 21.845ms */
__tcu_start_counter(HW_UDELAY_TIMER);
}
void udelay(unsigned int usec)
void udelay(unsigned int usec) /* Must be under 21845 us! */
{
if (!__tcu_ost_enabled())
if (!__tcu_counter_enabled(HW_UDELAY_TIMER))
init_delaytimer();
unsigned int now = REG_OST_OSTCNT;
unsigned short start = REG_TCU_TCNT(HW_UDELAY_TIMER);
/* Figure out how many ticks we need */
usec = (CFG_EXTAL / (4 * 1000 * 1000)) * (usec + 1);
while (REG_OST_OSTCNT - now < usec) { }
while (((REG_TCU_TCNT(HW_UDELAY_TIMER) - start) & 0xffff) < usec) { }
// while (start + usec < REG_TCU_TCNT(HW_UDELAY_TIMER)) { };
}
#else
void udelay(unsigned int usec)
@ -681,7 +688,7 @@ void ICODE_ATTR system_main(void)
for(i=0; i<IRQ_INTC_MAX; i++)
dis_irq(i);
#ifdef USE_HW_UDELAY
#ifdef HW_UDELAY_TIMER
init_delaytimer();
#endif