common: Use 64 bit writes per default

Also have a flag to fallback to 32 bit writes.

Signed-off-by: Tokunori Ikegami <[email protected]>

common.h

@@ -3,6 +3,7 @@
 #define _COMMON_H
 
 #include <string.h>
+#include <stdbool.h>
 
 #include "ccan/endian/endian.h"
 
@@ -42,14 +43,17 @@ static inline void mmio_write32(void *addr, uint32_t value)
 	*p = cpu_to_le32(value);
 }
 
-/* Access 64-bit registers as 2 32-bit; Some devices fail 64-bit MMIO. */
-static inline void mmio_write64(void *addr, uint64_t value)
+/* Access 64-bit registers as 2 32-bit if write32 flag set; Some devices fail 64-bit MMIO. */
+static inline void mmio_write64(void *addr, uint64_t value, bool write32)
 {
-	uint32_t *p = addr;
-	uint32_t low = value;
-	uint32_t high = value >> 32;
+	uint64_t *p = addr;
+
+	if (write32) {
+		mmio_write32(addr, value);
+		mmio_write32(addr + 1, value >> 32);
+		return;
+	}
 
-	*p = cpu_to_le32(low);
-	*(p + 1) = cpu_to_le32(high);
+	*p = cpu_to_le64(value);
 }
 #endif

nvme.c

@@ -5416,7 +5416,7 @@ static int get_register(int argc, char **argv, struct command *cmd, struct plugi
 static void nvme_set_register(void *bar, int offset, uint64_t value)
 {
 	if (nvme_is_64bit_reg(offset))
-		mmio_write64(bar + offset, value);
+		mmio_write64(bar + offset, value, false);
 	else
 		mmio_write32(bar + offset, value);
 }