linux-kernel - Re: [PATCH v2] mtd: parsers: bcm63xx: simplify CFE detection

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Message-Id: <779D37C7-58CB-49AF-8739-C34295B86FC4@gmail.com>
Date:   Thu, 11 Jun 2020 17:16:04 +0200
From:   Álvaro Fernández Rojas <noltari@...il.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     tsbogend@...ha.franken.de, Florian Fainelli <f.fainelli@...il.com>,
        bcm-kernel-feedback-list@...adcom.com, richard@....at,
        vigneshr@...com, Jonas Gorski <jonas.gorski@...il.com>,
        linus.walleij@...aro.org, linux-mips@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mtd@...ts.infradead.org
Subject: Re: [PATCH v2] mtd: parsers: bcm63xx: simplify CFE detection

Hi Miquel,

> El 11 jun 2020, a las 9:55, Miquel Raynal <miquel.raynal@...tlin.com> escribió:
> 
> Hi Álvaro,
> 
> Álvaro Fernández Rojas <noltari@...il.com> wrote on Mon,  8 Jun 2020
> 18:06:49 +0200:
> 
>> Instead of trying to parse CFE version string, which is customized by some
>> vendors, let's just check that "CFE1" was passed on argument 3.
>> 
>> Signed-off-by: Álvaro Fernández Rojas <noltari@...il.com>
>> Signed-off-by: Jonas Gorski <jonas.gorski@...il.com>
>> ---
>> v2: use CFE_EPTSEAL definition and avoid using an additional funtion.
>> 
>> drivers/mtd/parsers/bcm63xxpart.c | 29 ++++-------------------------
>> 1 file changed, 4 insertions(+), 25 deletions(-)
>> 
>> diff --git a/drivers/mtd/parsers/bcm63xxpart.c b/drivers/mtd/parsers/bcm63xxpart.c
>> index 78f90c6c18fd..493a75b2f266 100644
>> --- a/drivers/mtd/parsers/bcm63xxpart.c
>> +++ b/drivers/mtd/parsers/bcm63xxpart.c
>> @@ -22,6 +22,9 @@
>> #include <linux/mtd/partitions.h>
>> #include <linux/of.h>
>> 
>> +#include <asm/bootinfo.h>
>> +#include <asm/fw/cfe/cfe_api.h>
> 
> Are you sure both includes are needed?

asm/bootinfo.h is needed for fw_arg3 and asm/fw/cfe/cfe_api.h is needed for CFE_EPTSEAL.

> 
> I don't think it is a good habit to include asm/ headers, are you sure
> there is not another header doing it just fine?

Both are needed unless you want to add another definition of CFE_EPTSEAL value.
There are currently two CFE magic definitions, the one in asm/fw/cfe/cfe_api.h and another one in bcm47xxpart.c:
https://github.com/torvalds/linux/blob/master/arch/mips/include/asm/fw/cfe/cfe_api.h#L28
https://github.com/torvalds/linux/blob/master/drivers/mtd/parsers/bcm47xxpart.c#L33

> 
>> +
>> #define BCM963XX_CFE_BLOCK_SIZE		SZ_64K	/* always at least 64KiB */
>> 
>> #define BCM963XX_CFE_MAGIC_OFFSET	0x4e0
>> @@ -32,30 +35,6 @@
>> #define STR_NULL_TERMINATE(x) \
>> 	do { char *_str = (x); _str[sizeof(x) - 1] = 0; } while (0)
>> 
>> -static int bcm63xx_detect_cfe(struct mtd_info *master)
>> -{
>> -	char buf[9];
>> -	int ret;
>> -	size_t retlen;
>> -
>> -	ret = mtd_read(master, BCM963XX_CFE_VERSION_OFFSET, 5, &retlen,
>> -		       (void *)buf);
>> -	buf[retlen] = 0;
>> -
>> -	if (ret)
>> -		return ret;
>> -
>> -	if (strncmp("cfe-v", buf, 5) == 0)
>> -		return 0;
>> -
>> -	/* very old CFE's do not have the cfe-v string, so check for magic */
>> -	ret = mtd_read(master, BCM963XX_CFE_MAGIC_OFFSET, 8, &retlen,
>> -		       (void *)buf);
>> -	buf[retlen] = 0;
>> -
>> -	return strncmp("CFE1CFE1", buf, 8);
>> -}
>> -
>> static int bcm63xx_read_nvram(struct mtd_info *master,
>> 	struct bcm963xx_nvram *nvram)
>> {
>> @@ -138,7 +117,7 @@ static int bcm63xx_parse_cfe_partitions(struct mtd_info *master,
>> 	struct bcm963xx_nvram *nvram = NULL;
>> 	int ret;
>> 
>> -	if (bcm63xx_detect_cfe(master))
>> +	if (fw_arg3 != CFE_EPTSEAL)
>> 		return -EINVAL;
>> 
>> 	nvram = vzalloc(sizeof(*nvram));

Best regards,
Álvaro.