diff options
author | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2020-05-21 00:54:36 +0200 |
---|---|---|
committer | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2020-05-21 00:54:36 +0200 |
commit | 135d39dcedcedd1f44ea0bba52f15ac5922c114f (patch) | |
tree | 12379fc8ef7489eaca1c7245f8bd6af74c619a8f /drivers/mtd/devices/spear_smi.c | |
parent | 187764bd111b27783b6d68ffb3b3dbb3a9bafd38 (diff) | |
parent | 1279cd128bba968ebe0a2df7f7ae38bae90250ef (diff) |
Merge remote-tracking branch 'remotes/fslc/4.9-2.3.x-imx' into toradex_4.9-2.3.x-imx-next
Conflicts:
sound/soc/codecs/sgtl5000.c
sound/soc/fsl/imx-sgtl5000.c
Diffstat (limited to 'drivers/mtd/devices/spear_smi.c')
-rw-r--r-- | drivers/mtd/devices/spear_smi.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/drivers/mtd/devices/spear_smi.c b/drivers/mtd/devices/spear_smi.c index dd5069876537..4a7da5fde714 100644 --- a/drivers/mtd/devices/spear_smi.c +++ b/drivers/mtd/devices/spear_smi.c @@ -595,6 +595,26 @@ static int spear_mtd_read(struct mtd_info *mtd, loff_t from, size_t len, return 0; } +/* + * The purpose of this function is to ensure a memcpy_toio() with byte writes + * only. Its structure is inspired from the ARM implementation of _memcpy_toio() + * which also does single byte writes but cannot be used here as this is just an + * implementation detail and not part of the API. Not mentioning the comment + * stating that _memcpy_toio() should be optimized. + */ +static void spear_smi_memcpy_toio_b(volatile void __iomem *dest, + const void *src, size_t len) +{ + const unsigned char *from = src; + + while (len) { + len--; + writeb(*from, dest); + from++; + dest++; + } +} + static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank, void __iomem *dest, const void *src, size_t len) { @@ -617,7 +637,23 @@ static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank, ctrlreg1 = readl(dev->io_base + SMI_CR1); writel((ctrlreg1 | WB_MODE) & ~SW_MODE, dev->io_base + SMI_CR1); - memcpy_toio(dest, src, len); + /* + * In Write Burst mode (WB_MODE), the specs states that writes must be: + * - incremental + * - of the same size + * The ARM implementation of memcpy_toio() will optimize the number of + * I/O by using as much 4-byte writes as possible, surrounded by + * 2-byte/1-byte access if: + * - the destination is not 4-byte aligned + * - the length is not a multiple of 4-byte. + * Avoid this alternance of write access size by using our own 'byte + * access' helper if at least one of the two conditions above is true. + */ + if (IS_ALIGNED(len, sizeof(u32)) && + IS_ALIGNED((uintptr_t)dest, sizeof(u32))) + memcpy_toio(dest, src, len); + else + spear_smi_memcpy_toio_b(dest, src, len); writel(ctrlreg1, dev->io_base + SMI_CR1); |