diff options
| author |   Sivaprakash Murugesan <sivaprak@codeaurora.org> | 2020-06-12 13:28:16 +0530 |
|---|---|---|
| committer |   Miquel Raynal <miquel.raynal@bootlin.com> | 2020-06-26 08:35:10 +0200 |
| commit | cb272395dceef1652247dad08a50ed4153ffbd43 (patch) | |
| tree | 56e4e3eb12f7f773e2ce81c8556b4190822d209e /drivers/mtd | |
| parent | mtd: rawnand: qcom: avoid write to unavailable register (diff) | |
| download | linux-dev-cb272395dceef1652247dad08a50ed4153ffbd43.tar.xz linux-dev-cb272395dceef1652247dad08a50ed4153ffbd43.zip | |
mtd: rawnand: qcom: set BAM mode only if not set already
BAM is DMA controller on QCOM ipq platforms, BAM mode on NAND driver
is set by writing BAM_MODE_EN bit on NAND_CTRL register.
NAND_CTRL is an operational register and in BAM mode operational
registers are read only.
So, before enabling BAM mode by writing the NAND_CTRL register, check
if BAM mode was already enabled by the bootloader, and enable BAM mode
only if it is not enabled already.
Signed-off-by: Sivaprakash Murugesan <sivaprak@codeaurora.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/1591948696-16015-3-git-send-email-sivaprak@codeaurora.org
Diffstat (limited to 'drivers/mtd')
| -rw-r--r-- | drivers/mtd/nand/raw/qcom_nandc.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c index 78b5f211598c..bd7a7251429b 100644 --- a/drivers/mtd/nand/raw/qcom_nandc.c +++ b/drivers/mtd/nand/raw/qcom_nandc.c @@ -2784,7 +2784,16 @@ static int qcom_nandc_setup(struct qcom_nand_controller *nandc) /* enable ADM or BAM DMA */ if (nandc->props->is_bam) { nand_ctrl = nandc_read(nandc, NAND_CTRL); - nandc_write(nandc, NAND_CTRL, nand_ctrl | BAM_MODE_EN); + + /* + *NAND_CTRL is an operational registers, and CPU + * access to operational registers are read only + * in BAM mode. So update the NAND_CTRL register + * only if it is not in BAM mode. In most cases BAM + * mode will be enabled in bootloader + */ + if (!(nand_ctrl & BAM_MODE_EN)) + nandc_write(nandc, NAND_CTRL, nand_ctrl | BAM_MODE_EN); } else { nandc_write(nandc, NAND_FLASH_CHIP_SELECT, DM_EN); } |