vmu: Use blocking frame locking where possible

In some places in the VMU code, genwait_wait() is used, which means that
the calling function cannot run in interrupt context. Therefore, in
those places we can wait for the maple frame to lock as it is safe to
do so.

This fixes KallistiOS#1225.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>

Author: pcercuei

kernel/arch/dreamcast/hardware/maple/vmu.c

@@ -437,8 +437,7 @@ int vmu_block_read(maple_device_t *dev, uint16_t blocknum, uint8_t *buffer) {
     assert(dev != NULL);
 
     /* Lock the frame */
-    if(maple_frame_trylock(&dev->frame) < 0)
-        return MAPLE_EAGAIN;
+    maple_frame_lock(&dev->frame);
 
     /* This is (block << 24) | (phase << 8) | (partition (0 for all vmu)) */
     blkid = ((blocknum & 0xff) << 24) | ((blocknum >> 8) << 16);
@@ -516,8 +515,7 @@ static int vmu_block_write_internal(maple_device_t *dev, uint16_t blocknum, cons
     rv = MAPLE_EOK;
 
     /* Lock the frame. XXX: Priority inversion issues here. */
-    while(maple_frame_trylock(&dev->frame) < 0)
-        thd_pass();
+    maple_frame_lock(&dev->frame);
 
     /* Writes have to occur in four phases per block -- this is the
        way of flash memory, which you must erase an entire block
@@ -638,8 +636,7 @@ int vmu_set_datetime(maple_device_t *dev, time_t unix) {
     assert(btime); /* A failure here means an invalid unix timestamp was given. */
 
     /* Lock the frame */
-    if(maple_frame_trylock(&dev->frame) < 0)
-        return MAPLE_EAGAIN;
+    maple_frame_lock(&dev->frame);
 
     /* Reset the frame */
     maple_frame_init(&dev->frame);
@@ -687,8 +684,7 @@ int vmu_get_datetime(maple_device_t *dev, time_t *unix) {
         return MAPLE_EINVALID;
 
     /* Lock the frame */
-    if(maple_frame_trylock(&dev->frame) < 0)
-        return MAPLE_EAGAIN;
+    maple_frame_lock(&dev->frame);
 
     /* Reset the frame */
     maple_frame_init(&dev->frame);