From 2150e2ae747dd55e9e9683cc5783ba1cf6459d6d Mon Sep 17 00:00:00 2001
From: Bjorn Andersson <bjorn.andersson@linaro.org>
Date: Mon, 8 Feb 2016 16:30:25 -0800
Subject: [PATCH] rmtfs: Fetch rmtfs address from device-tree

The rmtfs address differes from platform to platform, so fetch these
from the device-tree node in /proc instead of hard coding them.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 sharedmem.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 79 insertions(+), 5 deletions(-)

diff --git a/sharedmem.c b/sharedmem.c
index bc89d01..00d85e2 100644
--- a/sharedmem.c
+++ b/sharedmem.c
@@ -1,4 +1,6 @@
 #include <sys/mman.h>
+#include <sys/types.h>
+#include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdbool.h>
@@ -8,11 +10,10 @@
 #include <unistd.h>
 #include "rmtfs.h"
 
-#define SHAREDMEM_BASE 0x0fd80000
-#define SHAREDMEM_SIZE 0x180000
+static int rmtfs_mem_enumerate(void);
 
-static uint64_t rmtfs_mem_address = SHAREDMEM_BASE;
-static uint64_t rmtfs_mem_size = SHAREDMEM_SIZE;
+static uint64_t rmtfs_mem_address;
+static uint64_t rmtfs_mem_size;
 static void *rmtfs_mem_base;
 static bool rmtfs_mem_busy;
 static int rmtfs_mem_fd;
@@ -20,15 +21,20 @@ static int rmtfs_mem_fd;
 int rmtfs_mem_open(void)
 {
 	void *base;
+	int ret;
 	int fd;
 
+	ret = rmtfs_mem_enumerate();
+	if (ret < 0)
+		return ret;
+
 	fd = open("/dev/mem", O_RDWR|O_SYNC);
 	if (fd < 0) {
 		fprintf(stderr, "failed to open /dev/mem\n");
 		return fd;
 	}
 
-	base = mmap(0, SHAREDMEM_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, SHAREDMEM_BASE);
+	base = mmap(0, rmtfs_mem_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, rmtfs_mem_address);
 	if (base == MAP_FAILED) {
 		fprintf(stderr, "failed to mmap: %s\n", strerror(errno));
 		return -errno;
@@ -86,3 +92,71 @@ void rmtfs_mem_close(void)
 	rmtfs_mem_fd = -1;
 	rmtfs_mem_base = MAP_FAILED;
 }
+
+static int rmtfs_mem_enumerate(void)
+{
+	union {
+		uint32_t dw[2];
+		uint64_t qw[2];
+	} reg;
+	struct dirent *de;
+	int basefd;
+	int dirfd;
+	int regfd;
+	DIR *dir;
+	int ret = 0;
+	int n;
+
+	basefd = open("/proc/device-tree/reserved-memory/", O_DIRECTORY);
+	dir = fdopendir(basefd);
+	if (!dir) {
+		fprintf(stderr,
+			"Unable to open reserved-memory device tree node: %s\n",
+			strerror(-errno));
+		close(basefd);
+		return -1;
+	}
+
+	while ((de = readdir(dir)) != NULL) {
+		if (strncmp(de->d_name, "rmtfs", 5) != 0)
+			continue;
+
+		dirfd = openat(basefd, de->d_name, O_DIRECTORY);
+		if (dirfd < 0) {
+			fprintf(stderr, "failed to open %s: %s\n",
+				de->d_name, strerror(-errno));
+			ret = -1;
+			goto out;
+		}
+
+		regfd = openat(dirfd, "reg", O_RDONLY);
+		if (regfd < 0) {
+			fprintf(stderr, "failed to open reg of %s: %s\n",
+				de->d_name, strerror(-errno));
+			ret = -1;
+			goto out;
+		}
+
+		n = read(regfd, &reg, sizeof(reg));
+		if (n == 2 * sizeof(uint32_t)) {
+			rmtfs_mem_address = be32toh(reg.dw[0]);
+			rmtfs_mem_size = be32toh(reg.dw[1]);
+		} else if (n == 2 * sizeof(uint64_t)) {
+			rmtfs_mem_address = be64toh(reg.qw[0]);
+			rmtfs_mem_size = be64toh(reg.qw[1]);
+		} else {
+			fprintf(stderr, "failed to read reg of %s: %s\n",
+				de->d_name, strerror(-errno));
+			ret = -1;
+		}
+
+		close(regfd);
+		close(dirfd);
+		break;
+	}
+
+out:
+	closedir(dir);
+	close(basefd);
+	return ret;
+}