bcm2835-sdhost: Fail gracefully with bad dtb

The logging timestamps depend on the existence of a bcm2835-system-timer
node. If this node doesn't exist, leave the logging disabled rather than
crashing.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

diff --git a/drivers/mmc/host/bcm2835-sdhost.c b/drivers/mmc/host/bcm2835-sdhost.c
index 4df705b..40eb557 100644 (file)
--- a/drivers/mmc/host/bcm2835-sdhost.c
+++ b/drivers/mmc/host/bcm2835-sdhost.c
@@ -247,19 +247,22 @@ static void log_init(struct device *dev)
        struct device_node *np;
 
        spin_lock_init(&log_lock);
-       sdhost_log_buf = dma_alloc_coherent(dev, LOG_SIZE, &sdhost_log_addr,
-                                            GFP_KERNEL);
-       if (sdhost_log_buf) {
-               np = of_find_compatible_node(NULL, NULL,
-                                            "brcm,bcm2835-system-timer");
-               pr_info("sdhost: log_buf @ %p (%llx)\n",
-                       sdhost_log_buf, (u64)sdhost_log_addr);
-               timer_base = of_iomap(np, 0);
-               if (!timer_base)
-                       pr_err("sdhost: failed to remap timer\n");
+
+       np = of_find_compatible_node(NULL, NULL,
+                                    "brcm,bcm2835-system-timer");
+       timer_base = of_iomap(np, 0);
+
+       if (timer_base) {
+               sdhost_log_buf = dma_alloc_coherent(dev, LOG_SIZE, &sdhost_log_addr,
+                                                       GFP_KERNEL);
+               if (sdhost_log_buf)
+                       pr_info("sdhost: log_buf @ %p (%llx)\n",
+                               sdhost_log_buf, (u64)sdhost_log_addr);
+               else
+                       pr_err("sdhost: failed to allocate log buf\n");
+       } else {
+               pr_err("sdhost: failed to remap timer - wrong dtb?\n");
        }
-       else
-               pr_err("sdhost: failed to allocate log buf\n");
 }
 
 static void log_event_impl(const char *event, u32 param1, u32 param2)