Re: [RESEND][PATCH] mtd: chips: Add support for PMC SPI Flash chips in m25p80.c

[Brian Norris <computersforpeace@gmail.com>]

+ Marek, since he's been reviewing (with dismay?) the increase in macro
flags in this driver. If there are any objections, I can amend/drop the
patch.

But in the meantime, I fixed a conflict with stuff that's been applied
since you submitted this patch, and applied to l2-mtd.git. Thanks!

Brian

On Mon, Jul 15, 2013 at 12:13:56PM +0200, Michel Stempin wrote:
> Add support for PMC (now Chingis, part of ISSI) Pm25LV512 (512 kBbit),
> Pm25LV010 (1 Mbit) and Pm25LQ032 (32 Mbit) SPI Flash chips.
> 
> This patch addresses two generations of PMC SPI Flash chips:
> 
>  - Pm25LV512 and Pm25LV010: these have 4KB sectors and 32KB
>    blocks. The 4KB sector erase uses a non-standard opcode
>    (0xd7). They do not support JEDEC RDID (0x9f), and so they can only
>    be detected by matching their name string with pre-configured
>    platform data. Because of the cascaded acquisitions, the datasheet
>    is no longer available on the current manufacturer's website,
>    although it is still commonly used in some recent wireless routers
>    (<https://forum.openwrt.org/viewtopic.php?pid=186360#p186360>). The
>    only public datasheet available seems to be on GeoCities:
>    <http://www.geocities.jp/scottle556/pdf/Pm25LV512-010.pdf>
> 
>  - Pm25LQ032: a newer generation flash, with 4KB sectors and 32KB
>    blocks. It uses the standard erase and JEDEC read-ID
>    opcodes. Manufacturer's datasheet is here:
>    <http://www.chingistek.com/img/Product_Files/Pm25LQ032C%20datasheet%20v1.6.1.pdf>
> 
> This patch is resent in order to take into account both Brian Norris
> remarks and this upstream patch:
> 
> commit e534ee4f9ca29fdb38eea4b0c53f2154fbd8c1ee
> Author: Krzysztof Mazur <krzysiek@podlesie.net>
> Date:   Fri Feb 22 15:51:05 2013 +0100
> 
>     mtd: m25p80: introduce SST_WRITE flag for SST byte programming
> 
>     Not all SST devices implement the SST byte programming command.
>     Some devices (like SST25VF064C) implement only standard m25p80 page
>     write command.
> 
>     Now SPI flash devices that need sst_write() are explicitly marked
>     with new SST_WRITE flag and the decision to use sst_write() is based
>     on this flag instead of manufacturer id.
> 
>     Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
>     Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
> 
> Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
> Signed-off-by: Michel Stempin <michel.stempin@wanadoo.fr>
> ---
>  drivers/mtd/devices/m25p80.c |   10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> index 2f3d2a5..55c8b5f 100644
> --- a/drivers/mtd/devices/m25p80.c
> +++ b/drivers/mtd/devices/m25p80.c
> @@ -43,6 +43,7 @@
>  #define	OPCODE_FAST_READ	0x0b	/* Read data bytes (high frequency) */
>  #define	OPCODE_PP		0x02	/* Page program (up to 256 bytes) */
>  #define	OPCODE_BE_4K		0x20	/* Erase 4KiB block */
> +#define	OPCODE_BE_4K_PMC	0xd7	/* Erase 4KiB block on PMC chips */
>  #define	OPCODE_BE_32K		0x52	/* Erase 32KiB block */
>  #define	OPCODE_CHIP_ERASE	0xc7	/* Erase whole flash chip */
>  #define	OPCODE_SE		0xd8	/* Sector erase (usually 64KiB) */
> @@ -682,6 +683,7 @@ struct flash_info {
>  #define	SECT_4K		0x01		/* OPCODE_BE_4K works uniformly */
>  #define	M25P_NO_ERASE	0x02		/* No erase command needed */
>  #define	SST_WRITE	0x04		/* use SST byte programming */
> +#define	SECT_4K_PMC	0x08		/* OPCODE_BE_4K_PMC works uniformly */
>  };
>  
>  #define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags)	\
> @@ -762,6 +764,11 @@ static const struct spi_device_id m25p_ids[] = {
>  	{ "n25q128a13",  INFO(0x20ba18, 0, 64 * 1024, 256, 0) },
>  	{ "n25q256a", INFO(0x20ba19, 0, 64 * 1024, 512, SECT_4K) },
>  
> +	/* PMC */
> +	{ "pm25lv512", INFO(0, 0, 32 * 1024, 2, SECT_4K_PMC) },
> +	{ "pm25lv010", INFO(0, 0, 32 * 1024, 4, SECT_4K_PMC) },
> +	{ "pm25lq032", INFO(0x7f9d46, 0, 64 * 1024,  64, SECT_4K) },
> +
>  	/* Spansion -- single (large) sector size only, at least
>  	 * for the chips listed here (without boot sectors).
>  	 */
> @@ -1014,6 +1021,9 @@ static int m25p_probe(struct spi_device *spi)
>  	if (info->flags & SECT_4K) {
>  		flash->erase_opcode = OPCODE_BE_4K;
>  		flash->mtd.erasesize = 4096;
> +	} else if (info->flags & SECT_4K_PMC) {
> +		flash->erase_opcode = OPCODE_BE_4K_PMC;
> +		flash->mtd.erasesize = 4096;
>  	} else {
>  		flash->erase_opcode = OPCODE_SE;
>  		flash->mtd.erasesize = info->sector_size;