x86: Add CBMEM console driver for coreboot

[karo-tx-uboot.git] / common / bouncebuf.c

diff --git a/common/bouncebuf.c b/common/bouncebuf.c
index 4f827f893d665d66963a7f32aeaea4f00222d9d2..1df12cdda07d04f80632190c09b841e85a774b45 100644 (file)
--- a/common/bouncebuf.c
+++ b/common/bouncebuf.c
@@ -27,21 +27,19 @@
 #include <errno.h>
 #include <bouncebuf.h>
 
-static int addr_aligned(void *data, size_t len)
+static int addr_aligned(struct bounce_buffer *state)
 {
        const ulong align_mask = ARCH_DMA_MINALIGN - 1;
 
        /* Check if start is aligned */
-       if ((ulong)data & align_mask) {
-               debug("Unaligned start address %p\n", data);
+       if ((ulong)state->user_buffer & align_mask) {
+               debug("Unaligned buffer address %p\n", state->user_buffer);
                return 0;
        }
 
-       data += len;
-
-       /* Check if end is aligned */
-       if ((ulong)data & align_mask) {
-               debug("Unaligned end address %p\n", data);
+       /* Check if length is aligned */
+       if (state->len != state->len_aligned) {
+               debug("Unaligned buffer length %d\n", state->len);
                return 0;
        }
 
@@ -49,44 +47,53 @@ static int addr_aligned(void *data, size_t len)
        return 1;
 }
 
-int bounce_buffer_start(void **data, size_t len, void **backup, uint8_t flags)
+int bounce_buffer_start(struct bounce_buffer *state, void *data,
+                       size_t len, unsigned int flags)
 {
-       void *tmp;
-       size_t alen;
-
-       if (addr_aligned(*data, len)) {
-               *backup = NULL;
-               return 0;
+       state->user_buffer = data;
+       state->bounce_buffer = data;
+       state->len = len;
+       state->len_aligned = roundup(len, ARCH_DMA_MINALIGN);
+       state->flags = flags;
+
+       if (!addr_aligned(state)) {
+               state->bounce_buffer = memalign(ARCH_DMA_MINALIGN,
+                                               state->len_aligned);
+               if (!state->bounce_buffer)
+                       return -ENOMEM;
+
+               if (state->flags & GEN_BB_READ)
+                       memcpy(state->bounce_buffer, state->user_buffer,
+                               state->len);
        }
 
-       alen = roundup(len, ARCH_DMA_MINALIGN);
-       tmp = memalign(ARCH_DMA_MINALIGN, alen);
-
-       if (!tmp)
-               return -ENOMEM;
-
-       if (flags & GEN_BB_READ)
-               memcpy(tmp, *data, len);
-
-       *backup = *data;
-       *data = tmp;
+       /*
+        * Flush data to RAM so DMA reads can pick it up,
+        * and any CPU writebacks don't race with DMA writes
+        */
+       flush_dcache_range((unsigned long)state->bounce_buffer,
+                               (unsigned long)(state->bounce_buffer) +
+                                       state->len_aligned);
 
        return 0;
 }
 
-int bounce_buffer_stop(void **data, size_t len, void **backup, uint8_t flags)
+int bounce_buffer_stop(struct bounce_buffer *state)
 {
-       void *tmp = *data;
+       if (state->flags & GEN_BB_WRITE) {
+               /* Invalidate cache so that CPU can see any newly DMA'd data */
+               invalidate_dcache_range((unsigned long)state->bounce_buffer,
+                                       (unsigned long)(state->bounce_buffer) +
+                                               state->len_aligned);
+       }
 
-       /* The buffer was already aligned, since "backup" is NULL. */
-       if (!*backup)
+       if (state->bounce_buffer == state->user_buffer)
                return 0;
 
-       if (flags & GEN_BB_WRITE)
-               memcpy(*backup, *data, len);
+       if (state->flags & GEN_BB_WRITE)
+               memcpy(state->user_buffer, state->bounce_buffer, state->len);
 
-       *data = *backup;
-       free(tmp);
+       free(state->bounce_buffer);
 
        return 0;
 }