mtd: denali: kill the NAND_MAX_PAGESIZE/NAND_MAX_OOBSIZE

This patch kills the NAND_MAX_PAGESIZE/NAND_MAX_OOBSIZE by the following
way:
 1.) change the @buf field of nand_buf{} from an array to a pointer.
     also remove the DENALI_BUF_SIZE macro.

 2.) Before we call the nand_scan_ident, we allocate a temporary buffer
     whose size is PAGE_SIZE.

 3.) After we finish the nand_scan_ident, we have already getten the
     page size and oob size. We will allocate the right buffer size
     again.

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

2 files changed, 31 insertions, 24 deletions

diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
index 3a3a47f60d28..c07cd573ad3a 100644
--- a/drivers/mtd/nand/denali.c
+++ b/drivers/mtd/nand/denali.c
@@ -125,7 +125,6 @@ static void reset_buf(struct denali_nand_info *denali)
 
 static void write_byte_to_buf(struct denali_nand_info *denali, uint8_t byte)
 {
-        BUG_ON(denali->buf.tail >= sizeof(denali->buf.buf));
         denali->buf.buf[denali->buf.tail++] = byte;
 }
 
@@ -1429,20 +1428,12 @@ int denali_init(struct denali_nand_info *denali)
                 }
         }
 
-        /* Is 32-bit DMA supported? */
-        ret = dma_set_mask(denali->dev, DMA_BIT_MASK(32));
-        if (ret) {
-                pr_err("Spectra: no usable DMA configuration\n");
-                return ret;
-        }
-        denali->buf.dma_buf = dma_map_single(denali->dev, denali->buf.buf,
-                                             DENALI_BUF_SIZE,
-                                             DMA_BIDIRECTIONAL);
+        /* allocate a temporary buffer for nand_scan_ident() */
+        denali->buf.buf = devm_kzalloc(denali->dev, PAGE_SIZE,
+                                        GFP_DMA | GFP_KERNEL);
+        if (!denali->buf.buf)
+                return -ENOMEM;
 
-        if (dma_mapping_error(denali->dev, denali->buf.dma_buf)) {
-                dev_err(denali->dev, "Spectra: failed to map DMA buffer\n");
-                return -EIO;
-        }
         denali->mtd.dev.parent = denali->dev;
         denali_hw_init(denali);
         denali_drv_init(denali);
@@ -1475,12 +1466,29 @@ int denali_init(struct denali_nand_info *denali)
                 goto failed_req_irq;
         }
 
-        /* MTD supported page sizes vary by kernel. We validate our
-         * kernel supports the device here.
-         */
-        if (denali->mtd.writesize > NAND_MAX_PAGESIZE + NAND_MAX_OOBSIZE) {
-                ret = -ENODEV;
-                pr_err("Spectra: device size not supported by this version of MTD.");
+        /* allocate the right size buffer now */
+        devm_kfree(denali->dev, denali->buf.buf);
+        denali->buf.buf = devm_kzalloc(denali->dev,
+                             denali->mtd.writesize + denali->mtd.oobsize,
+                             GFP_KERNEL);
+        if (!denali->buf.buf) {
+                ret = -ENOMEM;
+                goto failed_req_irq;
+        }
+
+        /* Is 32-bit DMA supported? */
+        ret = dma_set_mask(denali->dev, DMA_BIT_MASK(32));
+        if (ret) {
+                pr_err("Spectra: no usable DMA configuration\n");
+                goto failed_req_irq;
+        }
+
+        denali->buf.dma_buf = dma_map_single(denali->dev, denali->buf.buf,
+                             denali->mtd.writesize + denali->mtd.oobsize,
+                             DMA_BIDIRECTIONAL);
+        if (dma_mapping_error(denali->dev, denali->buf.dma_buf)) {
+                dev_err(denali->dev, "Spectra: failed to map DMA buffer\n");
+                ret = -EIO;
                 goto failed_req_irq;
         }
 
@@ -1602,7 +1610,8 @@ EXPORT_SYMBOL(denali_init);
 void denali_remove(struct denali_nand_info *denali)
 {
         denali_irq_cleanup(denali->irq, denali);
-        dma_unmap_single(denali->dev, denali->buf.dma_buf, DENALI_BUF_SIZE,
+        dma_unmap_single(denali->dev, denali->buf.dma_buf,
+                        denali->mtd.writesize + denali->mtd.oobsize,
                         DMA_BIDIRECTIONAL);
 }
 EXPORT_SYMBOL(denali_remove);
diff --git a/drivers/mtd/nand/denali.h b/drivers/mtd/nand/denali.h
index cec5712862c9..966817462421 100644
--- a/drivers/mtd/nand/denali.h
+++ b/drivers/mtd/nand/denali.h
@@ -455,12 +455,10 @@
 
 #define ECC_SECTOR_SIZE     512
 
-#define DENALI_BUF_SIZE         (NAND_MAX_PAGESIZE + NAND_MAX_OOBSIZE)
-
 struct nand_buf {
         int head;
         int tail;
-        uint8_t buf[DENALI_BUF_SIZE];
+        uint8_t *buf;
         dma_addr_t dma_buf;
 };