This repository has no description
add functions to specify delay for RPi 0 and RPi 3
+97
-4
+1
os/CMakeLists.txt
+1
os/CMakeLists.txt
+16
os/include/kernel/delays.h
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os/include/kernel/delays.h
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-1
os/include/kernel/random.h
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-1
os/include/kernel/random.h
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os/src/kernel/delays.c
+54
os/src/kernel/delays.c
···
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#include "kernel/delays.h"
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#include "peripherals/base.h"
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#include "kernel/mmio.h"
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enum
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{
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SYSTMR_LO = (MMIO_BASE + 0x00003004),
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SYSTMR_HI = (MMIO_BASE + 0x00003008),
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};
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void wait_cycles(uint32_t n)
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{
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if(n) while(n--) { asm volatile("nop"); }
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}
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#if defined(MODEL_3)
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void wait_msec(uint32_t n)
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{
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register unsigned long f, t, r;
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// get the current counter frequency
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asm volatile ("mrs %0, cntfrq_el0" : "=r"(f));
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// read the current counter
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asm volatile ("mrs %0, cntpct_el0" : "=r"(t));
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// calculate required count increase
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unsigned long i=((f/1000)*n)/1000;
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// loop while counter increase is less than i
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do{asm volatile ("mrs %0, cntpct_el0" : "=r"(r));}while(r-t<i);
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}
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#endif
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uint64_t get_system_timer()
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{
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unsigned int h=-1, l;
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// we must read MMIO area as two separate 32 bit reads
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h=mmio_read(SYSTMR_HI);
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l=mmio_read(SYSTMR_LO);
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// we have to repeat it if high word changed during read
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if(h!=mmio_read(SYSTMR_HI)) {
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h=mmio_read(SYSTMR_HI);
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l=mmio_read(SYSTMR_LO);
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}
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// compose long int value
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return ((uint64_t) h << 32) | l;
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}
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void wait_msec_st(uint32_t n)
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{
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unsigned long t=get_system_timer();
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// we must check if it's non-zero, because qemu does not emulate
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// system timer, and returning constant zero would mean infinite loop
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if(t) while(get_system_timer()-t < n);
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}
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-2
os/src/kernel/kernel.c
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os/src/kernel/kernel.c
···
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#include "common/string.h"
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#include "kernel/kerio.h"
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#include "kernel/uart.h"
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#include "kernel/delays.h"
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#if defined(AARCH_32)
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#include "kernel/atag.h"
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#include "kernel/gpu.h"
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#include "kernel/memory.h"
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#include "kernel/random.h"
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/*!
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* @brief Entry point for the kernel
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* @param r0 0
···
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#endif
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puts("Welcome to piOS!\n----------------\n\n");
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printf("Wait for 5 secs if it works!\n");
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wait_msec_st(5000000);
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printf("%d\n", rand(100, 500));
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uint32_t mem_size = get_mem_size((atag_t *)atags);
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printf("RAM size: %d MB\n\n", mem_size / 1024 / 1024);
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···
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{
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printf("ATTENTION YOU ARE IN UART MODE\n\n");
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uart_init();
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printf("Wait for 5 secs if it works!\n");
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wait_msec(5000000);
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printf("Architecture: AARCH_%d\n\n", 64);
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rand_init();
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printf("%d", rand(100, 500));
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printf("%d\n", rand(100, 500));
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while(1)
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{
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putc(getc());
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-1
os/src/kernel/random.c
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-1
os/src/kernel/random.c
···
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#include "kernel/mmio.h"
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#include "common/stdlib.h"
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#ifndef MODEL_3
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static uint32_t next = 1;
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uint32_t rand(const uint32_t min, const uint32_t max)
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{
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next = next * 1103515245 + 12345;
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divmod_t div = divmod(next / 65536, 32768);
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divmod_t t = divmod(div.mod, (max - min + 1));
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return t.mod + min;
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}
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#else
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enum
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{
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RNG_CTRL = (MMIO_BASE + 0x00104000),
···
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// available for reading; require at least one
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while(!(mmio_read(RNG_STATUS)>>24)) asm volatile("nop");
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divmod_t rand = divmod(mmio_read(RNG_DATA), (max-min));
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divmod_t rand = divmod(mmio_read(RNG_DATA), (max-min+1));
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return rand.mod + min;
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}
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#endif