linux-kernel - Re: [PATCH v3 2/3] mtd: spi-nor: Move m25p80 code in spi-nor.c

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Date:   Thu, 1 Aug 2019 07:52:05 +0200
From:   Boris Brezillon <boris.brezillon@...labora.com>
To:     Vignesh Raghavendra <vigneshr@...com>
Cc:     Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Tudor Ambarus <tudor.ambarus@...rochip.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Boris Brezillon <bbrezillon@...nel.org>,
        <linux-kernel@...r.kernel.org>, <linux-mtd@...ts.infradead.org>
Subject: Re: [PATCH v3 2/3] mtd: spi-nor: Move m25p80 code in spi-nor.c

On Thu, 1 Aug 2019 10:00:51 +0530
Vignesh Raghavendra <vigneshr@...com> wrote:

> From: Boris Brezillon <boris.brezillon@...tlin.com>
> 
> The m25p80 driver is actually a generic wrapper around the spi-mem
> layer. Not only the driver name is misleading, but we'd expect such a
> common logic to be directly available in the core. Another reason for
> moving this code is that SPI NOR controller drivers should
> progressively be replaced by SPI controller drivers implementing the
> spi_mem_ops interface, and when the conversion is done, we should have
> a single spi-nor driver directly interfacing with the spi-mem layer.
> 
> While moving the code we also fix a longstanding issue when
> non-DMA-able buffers are passed by the MTD layer.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@...tlin.com>
> Signed-off-by: Vignesh Raghavendra <vigneshr@...com>
> ---
> v3:
> Simplify register read/write by dropping spi_nor_exec_op() and using
> spi_mem_exec_op() directly
> Modify spi_nor_spimem_xfer_data() to drop "enum spi_nor_protocol proto"
> Fix misc coding style comments by Tudor
> 
> v2:
> Add docs for new functions added
> Add spi_nor_ prefix to new functions
> Incorporate Andrey's patches https://lkml.org/lkml/2019/4/1/32
> to avoid looping spi_nor_spimem_* APIs
> 
>  drivers/mtd/devices/Kconfig   |  18 -
>  drivers/mtd/devices/Makefile  |   1 -
>  drivers/mtd/devices/m25p80.c  | 347 -------------------
>  drivers/mtd/spi-nor/Kconfig   |   2 +
>  drivers/mtd/spi-nor/spi-nor.c | 632 ++++++++++++++++++++++++++++++++--
>  include/linux/mtd/spi-nor.h   |   3 +
>  6 files changed, 604 insertions(+), 399 deletions(-)
>  delete mode 100644 drivers/mtd/devices/m25p80.c
> 

[...]


> @@ -348,6 +530,16 @@ static int read_cr(struct spi_nor *nor)
>   */
>  static int write_sr(struct spi_nor *nor, u8 val)
>  {
> +	if (nor->spimem) {
> +		struct spi_mem_op op =
> +			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRSR, 1),
> +				   SPI_MEM_OP_NO_ADDR,
> +				   SPI_MEM_OP_NO_DUMMY,
> +				   SPI_MEM_OP_DATA_IN(1, nor->bouncebuf, 1));
> +
> +		return spi_mem_exec_op(nor->spimem, &op);
> +	}
> +
>  	nor->bouncebuf[0] = val;

The above line should be moved at the beginning of the function if you
want the spimem path to work correctly.

>  	return nor->write_reg(nor, SPINOR_OP_WRSR, nor->bouncebuf, 1);
>  }