mtd: nand: pxa3xx: Allocate data buffer on detected flash size

This commit replaces the currently hardcoded buffer size, by a
dynamic detection scheme. First a small 256 bytes buffer is allocated
so the device can be detected (using READID and friends commands).

After detection, this buffer is released and a new buffer is allocated
to acommodate the page size plus out-of-band size.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

1 files changed, 30 insertions, 15 deletions

diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
index 287997487b95..64c258ec0170 100644
--- a/drivers/mtd/nand/pxa3xx_nand.c
+++ b/drivers/mtd/nand/pxa3xx_nand.c
@@ -39,6 +39,13 @@
 #define NAND_STOP_DELAY         (2 * HZ/50)
 #define PAGE_CHUNK_SIZE         (2048)
 
+/*
+ * Define a buffer size for the initial command that detects the flash device:
+ * STATUS, READID and PARAM. The largest of these is the PARAM command,
+ * needing 256 bytes.
+ */
+#define INIT_BUFFER_SIZE        256
+
 /* registers and bit definitions */
 #define NDCR            (0x00) /* Control register */
 #define NDTR0CS0        (0x04) /* Timing Parameter 0 for CS0 */
@@ -164,6 +171,7 @@ struct pxa3xx_nand_info {
 
         unsigned int            buf_start;
         unsigned int            buf_count;
+        unsigned int            buf_size;
 
         /* DMA information */
         int                     drcmr_dat;
@@ -911,26 +919,20 @@ static int pxa3xx_nand_detect_config(struct pxa3xx_nand_info *info)
         return 0;
 }
 
-/* the maximum possible buffer size for large page with OOB data
- * is: 2048 + 64 = 2112 bytes, allocate a page here for both the
- * data buffer and the DMA descriptor
- */
-#define MAX_BUFF_SIZE   PAGE_SIZE
-
 #ifdef ARCH_HAS_DMA
 static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
 {
         struct platform_device *pdev = info->pdev;
-        int data_desc_offset = MAX_BUFF_SIZE - sizeof(struct pxa_dma_desc);
+        int data_desc_offset = info->buf_size - sizeof(struct pxa_dma_desc);
 
         if (use_dma == 0) {
-                info->data_buff = kmalloc(MAX_BUFF_SIZE, GFP_KERNEL);
+                info->data_buff = kmalloc(info->buf_size, GFP_KERNEL);
                 if (info->data_buff == NULL)
                         return -ENOMEM;
                 return 0;
         }
 
-        info->data_buff = dma_alloc_coherent(&pdev->dev, MAX_BUFF_SIZE,
+        info->data_buff = dma_alloc_coherent(&pdev->dev, info->buf_size,
                                 &info->data_buff_phys, GFP_KERNEL);
         if (info->data_buff == NULL) {
                 dev_err(&pdev->dev, "failed to allocate dma buffer\n");
@@ -944,7 +946,7 @@ static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
                                 pxa3xx_nand_data_dma_irq, info);
         if (info->data_dma_ch < 0) {
                 dev_err(&pdev->dev, "failed to request data dma\n");
-                dma_free_coherent(&pdev->dev, MAX_BUFF_SIZE,
+                dma_free_coherent(&pdev->dev, info->buf_size,
                                 info->data_buff, info->data_buff_phys);
                 return info->data_dma_ch;
         }
@@ -962,7 +964,7 @@ static void pxa3xx_nand_free_buff(struct pxa3xx_nand_info *info)
         struct platform_device *pdev = info->pdev;
         if (use_dma) {
                 pxa_free_dma(info->data_dma_ch);
-                dma_free_coherent(&pdev->dev, MAX_BUFF_SIZE,
+                dma_free_coherent(&pdev->dev, info->buf_size,
                                   info->data_buff, info->data_buff_phys);
         } else {
                 kfree(info->data_buff);
@@ -971,7 +973,7 @@ static void pxa3xx_nand_free_buff(struct pxa3xx_nand_info *info)
 #else
 static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
 {
-        info->data_buff = kmalloc(MAX_BUFF_SIZE, GFP_KERNEL);
+        info->data_buff = kmalloc(info->buf_size, GFP_KERNEL);
         if (info->data_buff == NULL)
                 return -ENOMEM;
         return 0;
@@ -1085,7 +1087,16 @@ KEEP_CONFIG:
         else
                 host->col_addr_cycles = 1;
 
+        /* release the initial buffer */
+        kfree(info->data_buff);
+
+        /* allocate the real data + oob buffer */
+        info->buf_size = mtd->writesize + mtd->oobsize;
+        ret = pxa3xx_nand_init_buff(info);
+        if (ret)
+                return ret;
         info->oob_buff = info->data_buff + mtd->writesize;
+
         if ((mtd->size >> chip->page_shift) > 65536)
                 host->row_addr_cycles = 3;
         else
@@ -1191,9 +1202,13 @@ static int alloc_nand_resource(struct platform_device *pdev)
         }
         info->mmio_phys = r->start;
 
-        ret = pxa3xx_nand_init_buff(info);
-        if (ret)
+        /* Allocate a buffer to allow flash detection */
+        info->buf_size = INIT_BUFFER_SIZE;
+        info->data_buff = kmalloc(info->buf_size, GFP_KERNEL);
+        if (info->data_buff == NULL) {
+                ret = -ENOMEM;
                 goto fail_disable_clk;
+        }
 
         /* initialize all interrupts to be disabled */
         disable_int(info, NDSR_MASK);
@@ -1211,7 +1226,7 @@ static int alloc_nand_resource(struct platform_device *pdev)
 
 fail_free_buf:
         free_irq(irq, info);
-        pxa3xx_nand_free_buff(info);
+        kfree(info->data_buff);
 fail_disable_clk:
         clk_disable_unprepare(info->clk);
         return ret;