nand_spl_simple: Add a simple NAND read function

To support UBI in SPL we need a simple NAND read function. Add one to
nand_spl_simple and keep it as simple as it goes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Acked-by: Scott Wood <oss@buserror.net>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>

diff --git a/drivers/mtd/nand/nand_spl_simple.c b/drivers/mtd/nand/nand_spl_simple.c
index 60a7607..55f48d3 100644 (file)
--- a/drivers/mtd/nand/nand_spl_simple.c
+++ b/drivers/mtd/nand/nand_spl_simple.c
@@ -209,6 +209,68 @@ static int nand_read_page(int block, int page, void *dst)
 }
 #endif
 
+#ifdef CONFIG_SPL_UBI
+/*
+ * Temporary storage for non NAND page aligned and non NAND page sized
+ * reads. Note: This does not support runtime detected FLASH yet, but
+ * that should be reasonably easy to fix by making the buffer large
+ * enough :)
+ */
+static u8 scratch_buf[CONFIG_SYS_NAND_PAGE_SIZE];
+
+/**
+ * nand_spl_read_block - Read data from physical eraseblock into a buffer
+ * @block:     Number of the physical eraseblock
+ * @offset:    Data offset from the start of @peb
+ * @len:       Data size to read
+ * @dst:       Address of the destination buffer
+ *
+ * This could be further optimized if we'd have a subpage read
+ * function in the simple code. On NAND which allows subpage reads
+ * this would spare quite some time to readout e.g. the VID header of
+ * UBI.
+ *
+ * Notes:
+ *     @offset + @len are not allowed to be larger than a physical
+ *     erase block. No sanity check done for simplicity reasons.
+ *
+ * To support runtime detected flash this needs to be extended by
+ * information about the actual flash geometry, but thats beyond the
+ * scope of this effort and for most applications where fast boot is
+ * required it is not an issue anyway.
+ */
+int nand_spl_read_block(int block, int offset, int len, void *dst)
+{
+       int page, read;
+
+       /* Calculate the page number */
+       page = offset / CONFIG_SYS_NAND_PAGE_SIZE;
+
+       /* Offset to the start of a flash page */
+       offset = offset % CONFIG_SYS_NAND_PAGE_SIZE;
+
+       while (len) {
+               /*
+                * Non page aligned reads go to the scratch buffer.
+                * Page aligned reads go directly to the destination.
+                */
+               if (offset || len < CONFIG_SYS_NAND_PAGE_SIZE) {
+                       nand_read_page(block, page, scratch_buf);
+                       read = min(len, CONFIG_SYS_NAND_PAGE_SIZE - offset);
+                       memcpy(dst, scratch_buf + offset, read);
+                       offset = 0;
+               } else {
+                       nand_read_page(block, page, dst);
+                       read = CONFIG_SYS_NAND_PAGE_SIZE;
+               }
+               page++;
+               len -= read;
+               dst += read;
+       }
+       return 0;
+}
+#endif
+
 int nand_spl_load_image(uint32_t offs, unsigned int size, void *dst)
 {
        unsigned int block, lastblock;

diff --git a/include/nand.h b/include/nand.h
index a4f0f92..627b217 100644 (file)
--- a/include/nand.h
+++ b/include/nand.h
@@ -122,6 +122,7 @@ int nand_unlock(struct mtd_info *mtd, loff_t start, size_t length,
 int nand_get_lock_status(struct mtd_info *mtd, loff_t offset);
 
 int nand_spl_load_image(uint32_t offs, unsigned int size, void *dst);
+int nand_spl_read_block(int block, int offset, int len, void *dst);
 void nand_deselect(void);
 
 #ifdef CONFIG_SYS_NAND_SELECT_DEVICE