acpi: Add an acpi command

It is useful to dump ACPI tables in U-Boot to see what has been generated.
Add a command to handle this.

To allow the command to find the tables, add a position into the global
data.

Support subcommands to list and dump the tables.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
diff --git a/cmd/acpi.c b/cmd/acpi.c
new file mode 100644
index 0000000..203bd93
--- /dev/null
+++ b/cmd/acpi.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2019 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+#include <common.h>
+#include <command.h>
+#include <mapmem.h>
+#include <acpi/acpi_table.h>
+#include <asm/acpi_table.h>
+#include <dm/acpi.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * dump_hdr() - Dump an ACPI header
+ *
+ * If the header is for FACS then it shows the revision information as well
+ *
+ * @hdr: ACPI header to dump
+ */
+static void dump_hdr(struct acpi_table_header *hdr)
+{
+	bool has_hdr = memcmp(hdr->signature, "FACS", ACPI_NAME_LEN);
+
+	printf("%.*s %08lx %06x", ACPI_NAME_LEN, hdr->signature,
+	       (ulong)map_to_sysmem(hdr), hdr->length);
+	if (has_hdr) {
+		printf(" (v%02d %.6s %.8s %u %.4s %d)\n", hdr->revision,
+		       hdr->oem_id, hdr->oem_table_id, hdr->oem_revision,
+		       hdr->aslc_id, hdr->aslc_revision);
+	} else {
+		printf("\n");
+	}
+}
+
+/**
+ * find_table() - Look up an ACPI table
+ *
+ * @sig: Signature of table (4 characters, upper case)
+ * @return pointer to table header, or NULL if not found
+ */
+struct acpi_table_header *find_table(const char *sig)
+{
+	struct acpi_rsdp *rsdp;
+	struct acpi_rsdt *rsdt;
+	int len, i, count;
+
+	rsdp = map_sysmem(gd->arch.acpi_start, 0);
+	if (!rsdp)
+		return NULL;
+	rsdt = map_sysmem(rsdp->rsdt_address, 0);
+	len = rsdt->header.length - sizeof(rsdt->header);
+	count = len / sizeof(u32);
+	for (i = 0; i < count; i++) {
+		struct acpi_table_header *hdr;
+
+		hdr = map_sysmem(rsdt->entry[i], 0);
+		if (!memcmp(hdr->signature, sig, ACPI_NAME_LEN))
+			return hdr;
+		if (!memcmp(hdr->signature, "FACP", ACPI_NAME_LEN)) {
+			struct acpi_fadt *fadt = (struct acpi_fadt *)hdr;
+
+			if (!memcmp(sig, "DSDT", ACPI_NAME_LEN) && fadt->dsdt)
+				return map_sysmem(fadt->dsdt, 0);
+			if (!memcmp(sig, "FACS", ACPI_NAME_LEN) &&
+			    fadt->firmware_ctrl)
+				return map_sysmem(fadt->firmware_ctrl, 0);
+		}
+	}
+
+	return NULL;
+}
+
+static int dump_table_name(const char *sig)
+{
+	struct acpi_table_header *hdr;
+
+	hdr = find_table(sig);
+	if (!hdr)
+		return -ENOENT;
+	printf("%.*s @ %08lx\n", ACPI_NAME_LEN, hdr->signature,
+	       (ulong)map_to_sysmem(hdr));
+	print_buffer(0, hdr, 1, hdr->length, 0);
+
+	return 0;
+}
+
+static void list_fadt(struct acpi_fadt *fadt)
+{
+	if (fadt->dsdt)
+		dump_hdr(map_sysmem(fadt->dsdt, 0));
+	if (fadt->firmware_ctrl)
+		dump_hdr(map_sysmem(fadt->firmware_ctrl, 0));
+}
+
+static int list_rsdt(struct acpi_rsdt *rsdt, struct acpi_xsdt *xsdt)
+{
+	int len, i, count;
+
+	dump_hdr(&rsdt->header);
+	if (xsdt)
+		dump_hdr(&xsdt->header);
+	len = rsdt->header.length - sizeof(rsdt->header);
+	count = len / sizeof(u32);
+	for (i = 0; i < count; i++) {
+		struct acpi_table_header *hdr;
+
+		if (!rsdt->entry[i])
+			break;
+		hdr = map_sysmem(rsdt->entry[i], 0);
+		dump_hdr(hdr);
+		if (!memcmp(hdr->signature, "FACP", ACPI_NAME_LEN))
+			list_fadt((struct acpi_fadt *)hdr);
+		if (xsdt) {
+			if (xsdt->entry[i] != rsdt->entry[i]) {
+				printf("   (xsdt mismatch %llx)\n",
+				       xsdt->entry[i]);
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int list_rsdp(struct acpi_rsdp *rsdp)
+{
+	struct acpi_rsdt *rsdt;
+	struct acpi_xsdt *xsdt;
+
+	printf("RSDP %08lx %06x (v%02d %.6s)\n", (ulong)map_to_sysmem(rsdp),
+	       rsdp->length, rsdp->revision, rsdp->oem_id);
+	rsdt = map_sysmem(rsdp->rsdt_address, 0);
+	xsdt = map_sysmem(rsdp->xsdt_address, 0);
+	list_rsdt(rsdt, xsdt);
+
+	return 0;
+}
+
+static int do_acpi_list(cmd_tbl_t *cmdtp, int flag, int argc,
+			char *const argv[])
+{
+	struct acpi_rsdp *rsdp;
+
+	rsdp = map_sysmem(gd->arch.acpi_start, 0);
+	if (!rsdp) {
+		printf("No ACPI tables present\n");
+		return 0;
+	}
+	printf("ACPI tables start at %lx\n", gd->arch.acpi_start);
+	list_rsdp(rsdp);
+
+	return 0;
+}
+
+static int do_acpi_dump(cmd_tbl_t *cmdtp, int flag, int argc,
+			char *const argv[])
+{
+	const char *name;
+	char sig[ACPI_NAME_LEN];
+	int ret;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+	name = argv[1];
+	if (strlen(name) != ACPI_NAME_LEN) {
+		printf("Table name '%s' must be four characters\n", name);
+		return CMD_RET_FAILURE;
+	}
+	str_to_upper(name, sig, -1);
+	ret = dump_table_name(sig);
+	if (ret) {
+		printf("Table '%.*s' not found\n", ACPI_NAME_LEN, sig);
+		return CMD_RET_FAILURE;
+	}
+
+	return 0;
+}
+
+static char acpi_help_text[] =
+	"list - list ACPI tables\n"
+	"acpi dump <name> - Dump ACPI table";
+
+U_BOOT_CMD_WITH_SUBCMDS(acpi, "ACPI tables", acpi_help_text,
+	U_BOOT_SUBCMD_MKENT(list, 1, 1, do_acpi_list),
+	U_BOOT_SUBCMD_MKENT(dump, 2, 1, do_acpi_dump));