rpi3: Detect board revision
Implement VideoCore mailbox interface driver and use it to get the board
revision identifier.
For now it is only used to print the model for debug purposes.
This wiki contains the documentation of the mailbox interface:
https://github.com/raspberrypi/firmware/wiki
Change-Id: I11943b99b52cc1409f4a195ebe58eb44ae5b1d6c
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/plat/rpi3/rpi3_mbox.c b/plat/rpi3/rpi3_mbox.c
new file mode 100644
index 0000000..77e17af
--- /dev/null
+++ b/plat/rpi3/rpi3_mbox.c
@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <arch_helpers.h>
+#include <debug.h>
+#include <mmio.h>
+#include <platform_def.h>
+
+#include "rpi3_hw.h"
+
+/* This struct must be aligned to 16 bytes */
+typedef struct __packed __aligned(16) rpi3_mbox_request {
+ uint32_t size; /* Buffer size in bytes */
+ uint32_t code; /* Request/response code */
+ uint32_t tags[0];
+} rpi3_mbox_request_t;
+
+#define RPI3_MBOX_BUFFER_SIZE U(256)
+static uint8_t __aligned(16) rpi3_mbox_buffer[RPI3_MBOX_BUFFER_SIZE];
+
+/* Constants to perform a request/check the status of a request. */
+#define RPI3_MBOX_PROCESS_REQUEST U(0x00000000)
+#define RPI3_MBOX_REQUEST_SUCCESSFUL U(0x80000000)
+#define RPI3_MBOX_REQUEST_ERROR U(0x80000001)
+
+/* Command constants */
+#define RPI3_TAG_HARDWARE_GET_BOARD_REVISION U(0x00010002)
+#define RPI3_TAG_END U(0x00000000)
+
+#define RPI3_TAG_REQUEST U(0x00000000)
+#define RPI3_TAG_IS_RESPONSE U(0x80000000) /* Set if response */
+#define RPI3_TAG_RESPONSE_LENGTH_MASK U(0x7FFFFFFF)
+
+#define RPI3_CHANNEL_ARM_TO_VC U(0x8)
+#define RPI3_CHANNEL_MASK U(0xF)
+
+#define RPI3_MAILBOX_MAX_RETRIES U(1000000)
+
+/*******************************************************************************
+ * Helpers to send requests to the VideoCore using the mailboxes.
+ ******************************************************************************/
+static void rpi3_vc_mailbox_request_send(void)
+{
+ uint32_t st, data;
+ uintptr_t resp_addr, addr;
+ unsigned int retries;
+
+ /* This is the location of the request buffer */
+ addr = (uintptr_t) &rpi3_mbox_buffer;
+
+ /* Make sure that the changes are seen by the VideoCore */
+ flush_dcache_range(addr, RPI3_MBOX_BUFFER_SIZE);
+
+ /* Wait until the outbound mailbox is empty */
+ retries = 0U;
+
+ do {
+ st = mmio_read_32(RPI3_MBOX_BASE + RPI3_MBOX1_STATUS_OFFSET);
+
+ retries++;
+ if (retries == RPI3_MAILBOX_MAX_RETRIES) {
+ ERROR("rpi3: mbox: Send request timeout\n");
+ return;
+ }
+
+ } while ((st & RPI3_MBOX_STATUS_EMPTY_MASK) == 0U);
+
+ /* Send base address of this message to start request */
+ mmio_write_32(RPI3_MBOX_BASE + RPI3_MBOX1_WRITE_OFFSET,
+ RPI3_CHANNEL_ARM_TO_VC | (uint32_t) addr);
+
+ /* Wait until the inbound mailbox isn't empty */
+ retries = 0U;
+
+ do {
+ st = mmio_read_32(RPI3_MBOX_BASE + RPI3_MBOX0_STATUS_OFFSET);
+
+ retries++;
+ if (retries == RPI3_MAILBOX_MAX_RETRIES) {
+ ERROR("rpi3: mbox: Receive response timeout\n");
+ return;
+ }
+
+ } while ((st & RPI3_MBOX_STATUS_EMPTY_MASK) != 0U);
+
+ /* Get location and channel */
+ data = mmio_read_32(RPI3_MBOX_BASE + RPI3_MBOX0_READ_OFFSET);
+
+ if ((data & RPI3_CHANNEL_MASK) != RPI3_CHANNEL_ARM_TO_VC) {
+ ERROR("rpi3: mbox: Wrong channel: 0x%08x\n", data);
+ panic();
+ }
+
+ resp_addr = (uintptr_t)(data & ~RPI3_CHANNEL_MASK);
+ if (addr != resp_addr) {
+ ERROR("rpi3: mbox: Unexpected address: 0x%08x\n", data);
+ panic();
+ }
+
+ /* Make sure that the data seen by the CPU is up to date */
+ inv_dcache_range(addr, RPI3_MBOX_BUFFER_SIZE);
+}
+
+/*******************************************************************************
+ * Request board revision. Returns the revision and 0 on success, -1 on error.
+ ******************************************************************************/
+int rpi3_vc_hardware_get_board_revision(uint32_t *revision)
+{
+ uint32_t tag_request_size = sizeof(uint32_t);
+ rpi3_mbox_request_t *req = (rpi3_mbox_request_t *) rpi3_mbox_buffer;
+
+ assert(revision != NULL);
+
+ VERBOSE("rpi3: mbox: Sending request at %p\n", (void *)req);
+
+ req->size = sizeof(rpi3_mbox_buffer);
+ req->code = RPI3_MBOX_PROCESS_REQUEST;
+
+ req->tags[0] = RPI3_TAG_HARDWARE_GET_BOARD_REVISION;
+ req->tags[1] = tag_request_size; /* Space available for the response */
+ req->tags[2] = RPI3_TAG_REQUEST;
+ req->tags[3] = 0; /* Placeholder for the response */
+
+ req->tags[4] = RPI3_TAG_END;
+
+ rpi3_vc_mailbox_request_send();
+
+ if (req->code != RPI3_MBOX_REQUEST_SUCCESSFUL) {
+ ERROR("rpi3: mbox: Code = 0x%08x\n", req->code);
+ return -1;
+ }
+
+ if (req->tags[2] != (RPI3_TAG_IS_RESPONSE | tag_request_size)) {
+ ERROR("rpi3: mbox: get board revision failed (0x%08x)\n",
+ req->tags[2]);
+ return -1;
+ }
+
+ *revision = req->tags[3];
+
+ return 0;
+}