RE: [PATCH 3/3] mtd: spi-nor: sf: Add clear flag status register support

Hou Zhiqiang
2015-08-19T12:28:35Z

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Hi Jagan,

> -----Original Message-----
> From: Jagan Teki [mailto:jteki@openedev.com]
> Sent: 2015Äê8ÔÂ19ÈÕ 17:57
> To: linux-mtd@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org; Jagan Teki; Hou Zhiqiang-B48286; Hu
> Mingkai-B21284; David Woodhouse; Brian Norris
> Subject: [PATCH 3/3] mtd: spi-nor: sf: Add clear flag status register
> support
>
> The clear flag status register operation was required by Micron SPI-NOR
> chips, which support FSR. And if an error bit of FSR have been set like
> protection, voltage, erase, and program, it must be cleared by the clear
> FSR operation.
>
> Signed-off-by: Jagan Teki <jteki@openedev.com>
> Cc: Hou Zhiqiang <B48286@freescale.com>
> Cc: Mingkai.Hu <Mingkai.Hu@freescale.com>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: Brian Norris <computersforpeace@gmail.com>
> ---
> drivers/mtd/spi-nor/spi-nor.c | 35 +++++++++++++++++++++++++++++++----
> include/linux/mtd/spi-nor.h | 9 +++++++++
> 2 files changed, 40 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-
> nor.c index f954d03..c5c472d5 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -100,6 +100,28 @@ static int read_fsr(struct spi_nor *nor) }
>
> /*
> + * Read the clear flag status register.
> + * The clear flag status register operation was required by Micron
> + * SPI-NOR chips, which support FSR. And if an error bit of FSR
> + * have been set like protection, voltage, erase, and program,
> + * it must be cleared by the clear FSR operation.
> + * Returns zero for FSR bits cleared and negative if error occurred.
> + */
> +static int read_cfsr(struct spi_nor *nor) {
> + int ret;
> + u8 val;
> +
> + ret = nor->read_reg(nor, SPINOR_OP_RDCFSR, &val, 1);

There should be a write_reg instead of read_reg.
There isn¡¯t a register named CFSR, and the command SPINOR_OP_RDCFSR
is used to clear the FSR, another words reset FSR to default value.

> + if (ret < 0) {
> + pr_err("error %d reading CFSR\n", ret);
> + return ret;
> + }
> +
> + return val;
> +}
> +
> +/*
> * Read configuration register, returning its value in the
> * location. Return the configuration register value.
> * Returns negative if error occured.
> @@ -209,10 +231,15 @@ static inline int spi_nor_sr_ready(struct spi_nor
> *nor) static inline int spi_nor_fsr_ready(struct spi_nor *nor) {
> int fsr = read_fsr(nor);
> - if (fsr < 0)
> - return fsr;
> - else
> - return fsr & FSR_READY;
> + if (fsr & FSR_ERR_MASK) {
> + pr_err("flag status(0x%x) error occured\n", fsr);
> + int cfsr = read_cfsr(nor);
> + if (cfsr < 0)
> + return cfsr;
> + return -1;
> + }
> +
> + return fsr & FSR_READY;
> }
>
> static int spi_nor_ready(struct spi_nor *nor) diff --git
> a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index
> c5a58c4..36c1681 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -35,6 +35,7 @@
> #define SPINOR_OP_RDID 0x9f /* Read JEDEC ID */
> #define SPINOR_OP_RDCR 0x35 /* Read configuration register */
> #define SPINOR_OP_RDFSR 0x70 /* Read flag status register */
> +#define SPINOR_OP_RDCFSR 0x50 /* Read clear flag status register */
>
> /* 4-byte address opcodes - used on Spansion and some Macronix flashes.
> */
> #define SPINOR_OP_READ4 0x13 /* Read data bytes (low
> frequency) */
> @@ -74,6 +75,14 @@
> /* Enhanced Volatile Configuration Register bits */
> #define EVCR_QUAD_EN_MICRON 0x80 /* Micron Quad I/O */
>
> +/* Flag Status Register Error bits */
> +#define FSR_ERR_PROT 0x2 /* Protection */
> +#define FSR_ERR_VOLT 0x8 /* Voltage on Vpp */
> +#define FSR_ERR_PROG 0x10 /* Program operation */
> +#define FSR_ERR_ERASE 0x20 /* Erase operation */
> +#define FSR_ERR_MASK (FSR_ERR_PROT | FSR_ERR_VOLT | \
> + FSR_ERR_PROG | FSR_ERR_ERASE)
> +
> /* Flag Status Register bits */
> #define FSR_READY 0x80
>
> --
> 1.9.1

Thanks,
Zhiqiang
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