mbox.c
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/*
* (C) Copyright 2012 Stephen Warren
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/io.h>
#include <asm/arch/mbox.h>
#include <phys2bus.h>
#define TIMEOUT 1000 /* ms */
int bcm2835_mbox_call_raw(u32 chan, u32 send, u32 *recv)
{
struct bcm2835_mbox_regs *regs =
(struct bcm2835_mbox_regs *)BCM2835_MBOX_PHYSADDR;
ulong endtime = get_timer(0) + TIMEOUT;
u32 val;
debug("time: %lu timeout: %lu\n", get_timer(0), endtime);
if (send & BCM2835_CHAN_MASK) {
printf("mbox: Illegal mbox data 0x%08x\n", send);
return -1;
}
/* Drain any stale responses */
for (;;) {
val = readl(®s->status);
if (val & BCM2835_MBOX_STATUS_RD_EMPTY)
break;
if (get_timer(0) >= endtime) {
printf("mbox: Timeout draining stale responses\n");
return -1;
}
val = readl(®s->read);
}
/* Wait for space to send */
for (;;) {
val = readl(®s->status);
if (!(val & BCM2835_MBOX_STATUS_WR_FULL))
break;
if (get_timer(0) >= endtime) {
printf("mbox: Timeout waiting for send space\n");
return -1;
}
}
/* Send the request */
val = BCM2835_MBOX_PACK(chan, send);
debug("mbox: TX raw: 0x%08x\n", val);
writel(val, ®s->write);
/* Wait for the response */
for (;;) {
val = readl(®s->status);
if (!(val & BCM2835_MBOX_STATUS_RD_EMPTY))
break;
if (get_timer(0) >= endtime) {
printf("mbox: Timeout waiting for response\n");
return -1;
}
}
/* Read the response */
val = readl(®s->read);
debug("mbox: RX raw: 0x%08x\n", val);
/* Validate the response */
if (BCM2835_MBOX_UNPACK_CHAN(val) != chan) {
printf("mbox: Response channel mismatch\n");
return -1;
}
*recv = BCM2835_MBOX_UNPACK_DATA(val);
return 0;
}
#ifdef DEBUG
void dump_buf(struct bcm2835_mbox_hdr *buffer)
{
u32 *p;
u32 words;
int i;
p = (u32 *)buffer;
words = buffer->buf_size / 4;
for (i = 0; i < words; i++)
printf(" 0x%04x: 0x%08x\n", i * 4, p[i]);
}
#endif
int bcm2835_mbox_call_prop(u32 chan, struct bcm2835_mbox_hdr *buffer)
{
int ret;
u32 rbuffer;
struct bcm2835_mbox_tag_hdr *tag;
int tag_index;
#ifdef DEBUG
printf("mbox: TX buffer\n");
dump_buf(buffer);
#endif
flush_dcache_range((unsigned long)buffer,
(unsigned long)((void *)buffer +
roundup(buffer->buf_size, ARCH_DMA_MINALIGN)));
ret = bcm2835_mbox_call_raw(chan,
phys_to_bus((unsigned long)buffer),
&rbuffer);
if (ret)
return ret;
invalidate_dcache_range((unsigned long)buffer,
(unsigned long)((void *)buffer +
roundup(buffer->buf_size, ARCH_DMA_MINALIGN)));
if (rbuffer != phys_to_bus((unsigned long)buffer)) {
printf("mbox: Response buffer mismatch\n");
return -1;
}
#ifdef DEBUG
printf("mbox: RX buffer\n");
dump_buf(buffer);
#endif
/* Validate overall response status */
if (buffer->code != BCM2835_MBOX_RESP_CODE_SUCCESS) {
printf("mbox: Header response code invalid\n");
return -1;
}
/* Validate each tag's response status */
tag = (void *)(buffer + 1);
tag_index = 0;
while (tag->tag) {
if (!(tag->val_len & BCM2835_MBOX_TAG_VAL_LEN_RESPONSE)) {
printf("mbox: Tag %d missing val_len response bit\n",
tag_index);
return -1;
}
/*
* Clear the reponse bit so clients can just look right at the
* length field without extra processing
*/
tag->val_len &= ~BCM2835_MBOX_TAG_VAL_LEN_RESPONSE;
tag = (void *)(((u8 *)tag) + sizeof(*tag) + tag->val_buf_size);
tag_index++;
}
return 0;
}