mtd: spi-nor: sfdp: add/use local variable in spi_nor_parse_bfpt()

Despite of how spi_nor_parse_bfpt() abuses the structure fields during
their calculation, gcc manages to make some decent code out of that. :-)
Yet adding a local variable to store the BFPT DWORDs during calculations
still saves 12 bytes of the object code (AArch64 gcc 4.8.5)...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index ddb4808..d67182c 100644 (file)
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -437,7 +437,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
        struct sfdp_bfpt bfpt;
        size_t len;
        int i, cmd, err;
-       u32 addr;
+       u32 addr, val;
        u16 half;
        u8 erase_mask;
 
@@ -473,21 +473,21 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
        }
 
        /* Flash Memory Density (in bits). */
-       params->size = bfpt.dwords[BFPT_DWORD(2)];
-       if (params->size & BIT(31)) {
-               params->size &= ~BIT(31);
+       val = bfpt.dwords[BFPT_DWORD(2)];
+       if (val & BIT(31)) {
+               val &= ~BIT(31);
 
                /*
                 * Prevent overflows on params->size. Anyway, a NOR of 2^64
                 * bits is unlikely to exist so this error probably means
                 * the BFPT we are reading is corrupted/wrong.
                 */
-               if (params->size > 63)
+               if (val > 63)
                        return -EINVAL;
 
-               params->size = 1ULL << params->size;
+               params->size = 1ULL << val;
        } else {
-               params->size++;
+               params->size = val + 1;
        }
        params->size >>= 3; /* Convert to bytes. */
 
@@ -554,10 +554,10 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
                                                params);
 
        /* Page size: this field specifies 'N' so the page size = 2^N bytes. */
-       params->page_size = bfpt.dwords[BFPT_DWORD(11)];
-       params->page_size &= BFPT_DWORD11_PAGE_SIZE_MASK;
-       params->page_size >>= BFPT_DWORD11_PAGE_SIZE_SHIFT;
-       params->page_size = 1U << params->page_size;
+       val = bfpt.dwords[BFPT_DWORD(11)];
+       val &= BFPT_DWORD11_PAGE_SIZE_MASK;
+       val >>= BFPT_DWORD11_PAGE_SIZE_SHIFT;
+       params->page_size = 1U << val;
 
        /* Quad Enable Requirements. */
        switch (bfpt.dwords[BFPT_DWORD(15)] & BFPT_DWORD15_QER_MASK) {