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SubjectRe: [PATCH v1 1/1] mtd: mtk-nor: set controller's address width according to nor flash
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Hi Guochun,

Le 05/04/2017 à 10:37, Guochun Mao a écrit :
> When nor's size larger than 16MByte, nor's address width maybe
> set to 3 or 4, and controller should change address width according
> to nor's setting.
>
> Signed-off-by: Guochun Mao <guochun.mao@mediatek.com>
> ---
> drivers/mtd/spi-nor/mtk-quadspi.c | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/drivers/mtd/spi-nor/mtk-quadspi.c b/drivers/mtd/spi-nor/mtk-quadspi.c
> index e661877..b637770 100644
> --- a/drivers/mtd/spi-nor/mtk-quadspi.c
> +++ b/drivers/mtd/spi-nor/mtk-quadspi.c
> @@ -104,6 +104,8 @@
> #define MTK_NOR_MAX_RX_TX_SHIFT 6
> /* can shift up to 56 bits (7 bytes) transfer by MTK_NOR_PRG_CMD */
> #define MTK_NOR_MAX_SHIFT 7
> +/* nor controller 4-byte address mode enable bit */
> +#define MTK_NOR_4B_ADDR_EN BIT(4)
>
> /* Helpers for accessing the program data / shift data registers */
> #define MTK_NOR_PRG_REG(n) (MTK_NOR_PRGDATA0_REG + 4 * (n))
> @@ -230,10 +232,35 @@ static int mt8173_nor_write_buffer_disable(struct mt8173_nor *mt8173_nor)
> 10000);
> }
>
> +static void mt8173_nor_set_addr_width(struct mt8173_nor *mt8173_nor)
> +{
> + u8 val;
> + struct spi_nor *nor = &mt8173_nor->nor;
> +
> + val = readb(mt8173_nor->base + MTK_NOR_DUAL_REG);
> +
> + switch (nor->addr_width) {
> + case 3:
> + val &= ~MTK_NOR_4B_ADDR_EN;
> + break;
> + case 4:
> + val |= MTK_NOR_4B_ADDR_EN;
> + break;
> + default:
> + dev_warn(mt8173_nor->dev, "Unexpected address width %u.\n",
> + nor->addr_width);
> + break;
> + }
> +
> + writeb(val, mt8173_nor->base + MTK_NOR_DUAL_REG);
> +}
> +
> static void mt8173_nor_set_addr(struct mt8173_nor *mt8173_nor, u32 addr)
> {
> int i;
>
> + mt8173_nor_set_addr_width(mt8173_nor);
> +
> for (i = 0; i < 3; i++) {

Should it be 'i < nor->addr_width' instead of 'i < 3' ?
Does it work when accessing data after 128Mbit ?

Best regards,

Cyrille

> writeb(addr & 0xff, mt8173_nor->base + MTK_NOR_RADR0_REG + i * 4);
> addr >>= 8;
>

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