Commit cb272395 authored Jun 12, 2020 by Sivaprakash Murugesan Committed by Miquel Raynal Jun 26, 2020

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

parent 443440cc

drivers/mtd/nand/raw/qcom_nandc.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -2784,6 +2784,15 @@ 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);

		/*
		*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);

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