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139 lines
2.8 KiB
139 lines
2.8 KiB
#include "htif.h"
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#include "atomic.h"
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#include "mtrap.h"
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#include "fdt.h"
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#include <string.h>
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extern uint64_t __htif_base;
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volatile uint64_t tohost __attribute__((section(".htif")));
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volatile uint64_t fromhost __attribute__((section(".htif")));
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volatile int htif_console_buf;
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static spinlock_t htif_lock = SPINLOCK_INIT;
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uintptr_t htif;
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#define TOHOST(base_int) (uint64_t *)(base_int + TOHOST_OFFSET)
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#define FROMHOST(base_int) (uint64_t *)(base_int + FROMHOST_OFFSET)
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#define TOHOST_OFFSET ((uintptr_t)tohost - (uintptr_t)__htif_base)
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#define FROMHOST_OFFSET ((uintptr_t)fromhost - (uintptr_t)__htif_base)
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static void __check_fromhost()
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{
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uint64_t fh = fromhost;
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if (!fh)
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return;
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fromhost = 0;
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// this should be from the console
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assert(FROMHOST_DEV(fh) == 1);
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switch (FROMHOST_CMD(fh)) {
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case 0:
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htif_console_buf = 1 + (uint8_t)FROMHOST_DATA(fh);
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break;
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case 1:
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break;
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default:
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assert(0);
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}
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}
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static void __set_tohost(uintptr_t dev, uintptr_t cmd, uintptr_t data)
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{
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while (tohost)
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__check_fromhost();
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tohost = TOHOST_CMD(dev, cmd, data);
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}
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int htif_console_getchar()
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{
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spinlock_lock(&htif_lock);
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__check_fromhost();
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int ch = htif_console_buf;
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if (ch >= 0) {
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htif_console_buf = -1;
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__set_tohost(1, 0, 0);
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}
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spinlock_unlock(&htif_lock);
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return ch - 1;
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}
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static void do_tohost_fromhost(uintptr_t dev, uintptr_t cmd, uintptr_t data)
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{
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spinlock_lock(&htif_lock);
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__set_tohost(dev, cmd, data);
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while (1) {
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uint64_t fh = fromhost;
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if (fh) {
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if (FROMHOST_DEV(fh) == dev && FROMHOST_CMD(fh) == cmd) {
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fromhost = 0;
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break;
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}
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__check_fromhost();
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}
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}
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spinlock_unlock(&htif_lock);
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}
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void htif_syscall(uintptr_t arg)
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{
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do_tohost_fromhost(0, 0, arg);
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}
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void htif_console_putchar(uint8_t ch)
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{
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spinlock_lock(&htif_lock);
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__set_tohost(1, 1, ch);
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spinlock_unlock(&htif_lock);
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}
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void htif_poweroff()
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{
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while (1) {
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fromhost = 0;
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tohost = 1;
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}
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}
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struct htif_scan
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{
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int compat;
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};
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static void htif_open(const struct fdt_scan_node *node, void *extra)
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{
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struct htif_scan *scan = (struct htif_scan *)extra;
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memset(scan, 0, sizeof(*scan));
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}
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static void htif_prop(const struct fdt_scan_prop *prop, void *extra)
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{
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struct htif_scan *scan = (struct htif_scan *)extra;
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if (!strcmp(prop->name, "compatible") && !strcmp((const char*)prop->value, "ucb,htif0")) {
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scan->compat = 1;
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}
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}
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static void htif_done(const struct fdt_scan_node *node, void *extra)
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{
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struct htif_scan *scan = (struct htif_scan *)extra;
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if (!scan->compat) return;
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htif = 1;
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}
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void query_htif(uintptr_t fdt)
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{
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struct fdt_cb cb;
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struct htif_scan scan;
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memset(&cb, 0, sizeof(cb));
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cb.open = htif_open;
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cb.prop = htif_prop;
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cb.done = htif_done;
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cb.extra = &scan;
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fdt_scan(fdt, &cb);
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}
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