sparc: Add mutex for set property calls.

On some platforms, the I2C controller is shared between the OS and
OBP.  OBP uses this I2C controller to access the EEPROM, and thus is
programmed when the kernel calls prom_setprop().

Wrap such calls with the new of_set_property_mutex.

Relevant I2C bus drivers can grab this mutex around top-level I2C
operations to provide the proper protection.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/include/asm/prom.h b/arch/sparc/include/asm/prom.h
index fd55522481cd9dc0d14a14302446dff9d13017ee..b5efc4d85234445b96ac140557d09ebe854d8437 100644 (file)
--- a/arch/sparc/include/asm/prom.h
+++ b/arch/sparc/include/asm/prom.h
@@ -18,6 +18,7 @@
  */
 #include <linux/types.h>
 #include <linux/proc_fs.h>
+#include <linux/mutex.h>
 #include <asm/atomic.h>
 
 #define OF_ROOT_NODE_ADDR_CELLS_DEFAULT        2
@@ -73,6 +74,7 @@ struct of_irq_controller {
 
 extern struct device_node *of_find_node_by_cpuid(int cpuid);
 extern int of_set_property(struct device_node *node, const char *name, void *val, int len);
+extern struct mutex of_set_property_mutex;
 extern int of_getintprop_default(struct device_node *np,
                                 const char *name,
                                 int def);

diff --git a/arch/sparc/kernel/prom.c b/arch/sparc/kernel/prom.c
index cd4fb79aa3a8e185f12d8bfcd8ec90960e2a40ff..43e862406822c299ba3e25d0f28bb539eb646f37 100644 (file)
--- a/arch/sparc/kernel/prom.c
+++ b/arch/sparc/kernel/prom.c
@@ -54,6 +54,9 @@ int of_getintprop_default(struct device_node *np, const char *name, int def)
 }
 EXPORT_SYMBOL(of_getintprop_default);
 
+DEFINE_MUTEX(of_set_property_mutex);
+EXPORT_SYMBOL(of_set_property_mutex);
+
 int of_set_property(struct device_node *dp, const char *name, void *val, int len)
 {
        struct property **prevp;
@@ -77,7 +80,10 @@ int of_set_property(struct device_node *dp, const char *name, void *val, int len
                        void *old_val = prop->value;
                        int ret;
 
+                       mutex_lock(&of_set_property_mutex);
                        ret = prom_setprop(dp->node, (char *) name, val, len);
+                       mutex_unlock(&of_set_property_mutex);
+
                        err = -EINVAL;
                        if (ret >= 0) {
                                prop->value = new_val;

diff --git a/arch/sparc64/kernel/prom.c b/arch/sparc64/kernel/prom.c
index 3c048ac4e63859394ea7f28c4a75c91daec9df40..922dd612612e14c7693cf6f9fb1ce744c0936482 100644 (file)
--- a/arch/sparc64/kernel/prom.c
+++ b/arch/sparc64/kernel/prom.c
@@ -59,6 +59,9 @@ int of_getintprop_default(struct device_node *np, const char *name, int def)
 }
 EXPORT_SYMBOL(of_getintprop_default);
 
+DEFINE_MUTEX(of_set_property_mutex);
+EXPORT_SYMBOL(of_set_property_mutex);
+
 int of_set_property(struct device_node *dp, const char *name, void *val, int len)
 {
        struct property **prevp;
@@ -82,7 +85,10 @@ int of_set_property(struct device_node *dp, const char *name, void *val, int len
                        void *old_val = prop->value;
                        int ret;
 
+                       mutex_lock(&of_set_property_mutex);
                        ret = prom_setprop(dp->node, name, val, len);
+                       mutex_unlock(&of_set_property_mutex);
+
                        err = -EINVAL;
                        if (ret >= 0) {
                                prop->value = new_val;