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mtd: phram: Allow the user to set the erase page size.

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Permit the user to specify the erase page size as a parameter.
This solves two problems:

- phram can access images made by mkfs.jffs2.  mkfs.jffs2 won't
create images with erase sizes less than 8KiB; many architectures
define PAGE_SIZE as 4KiB.

- Allows more effective use of small capacity devices.  JFFS2
needs somewhere between 2 and 5 empty pages for garbage collection;
and for an NVRAM part with only 32KiB of space, a smaller erase page
allows much better utilization in applications where garbage collection
is important.

Signed-off-by: Patrick O'Grady <patrick@baymotion.com>
Reviewed-by: Joern Engel <joern@logfs.org>
Link: https://lore.kernel.org/lkml/CAJ7m5OqYv_=JB9NhHsqBsa8YU0DFRoP7C+W10PY22wonAGJK=A@mail.gmail.com/
[Guohua Zhong: fix token array index out of bounds and update patch for kernel master branch]
Signed-off-by: Guohua Zhong <zhongguohua1@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201207095529.20896-1-zhongguohua1@huawei.com
This commit is contained in:
Patrick O'Grady 2020-12-07 17:55:29 +08:00 committed by Miquel Raynal
parent 1ca71415f0
commit ffad560394
1 changed files with 34 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

52
drivers/mtd/devices/phram.c
View file

@ -6,14 +6,14 @@
* Usage:
*
* one commend line parameter per device, each in the form:
* phram=<name>,<start>,<len>
* phram=<name>,<start>,<len>[,<erasesize>]
* <name> may be up to 63 characters.
* <start> and <len> can be octal, decimal or hexadecimal. If followed
* <start>, <len>, and <erasesize> can be octal, decimal or hexadecimal. If followed
* by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
* gigabytes.
* gigabytes. <erasesize> is optional and defaults to PAGE_SIZE.
*
* Example:
* phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
* phram=swap,64Mi,128Mi phram=test,900Mi,1Mi,64Ki
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@ -26,6 +26,7 @@
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <asm/div64.h>
struct phram_mtd_list {
struct mtd_info mtd;
@ -88,7 +89,7 @@ static void unregister_devices(void)
}
}
static int register_device(char *name, phys_addr_t start, size_t len)
static int register_device(char *name, phys_addr_t start, size_t len, uint32_t erasesize)
{
struct phram_mtd_list *new;
int ret = -ENOMEM;
@ -115,7 +116,7 @@ static int register_device(char *name, phys_addr_t start, size_t len)
new->mtd._write = phram_write;
new->mtd.owner = THIS_MODULE;
new->mtd.type = MTD_RAM;
new->mtd.erasesize = PAGE_SIZE;
new->mtd.erasesize = erasesize;
new->mtd.writesize = 1;
ret = -EAGAIN;
@ -204,22 +205,23 @@ static inline void kill_final_newline(char *str)
static int phram_init_called;
/*
* This shall contain the module parameter if any. It is of the form:
* - phram=<device>,<address>,<size> for module case
* - phram.phram=<device>,<address>,<size> for built-in case
* We leave 64 bytes for the device name, 20 for the address and 20 for the
* size.
* Example: phram.phram=rootfs,0xa0000000,512Mi
* - phram=<device>,<address>,<size>[,<erasesize>] for module case
* - phram.phram=<device>,<address>,<size>[,<erasesize>] for built-in case
* We leave 64 bytes for the device name, 20 for the address , 20 for the
* size and 20 for the erasesize.
* Example: phram.phram=rootfs,0xa0000000,512Mi,65536
*/
static char phram_paramline[64 + 20 + 20];
static char phram_paramline[64 + 20 + 20 + 20];
#endif
static int phram_setup(const char *val)
{
char buf[64 + 20 + 20], *str = buf;
char *token[3];
char buf[64 + 20 + 20 + 20], *str = buf;
char *token[4];
char *name;
uint64_t start;
uint64_t len;
uint64_t erasesize = PAGE_SIZE;
int i, ret;
if (strnlen(val, sizeof(buf)) >= sizeof(buf))
@ -228,7 +230,7 @@ static int phram_setup(const char *val)
strcpy(str, val);
kill_final_newline(str);
for (i = 0; i < 3; i++)
for (i = 0; i < 4; i++)
token[i] = strsep(&str, ",");
if (str)
@ -253,11 +255,25 @@ static int phram_setup(const char *val)
goto error;
}
ret = register_device(name, start, len);
if (token[3]) {
ret = parse_num64(&erasesize, token[3]);
if (ret) {
parse_err("illegal erasesize\n");
goto error;
}
}
if (len == 0 || erasesize == 0 || erasesize > len
|| erasesize > UINT_MAX || do_div(len, (uint32_t)erasesize) != 0) {
parse_err("illegal erasesize or len\n");
goto error;
}
ret = register_device(name, start, len, (uint32_t)erasesize);
if (ret)
goto error;
pr_info("%s device: %#llx at %#llx\n", name, len, start);
pr_info("%s device: %#llx at %#llx for erasesize %#llx\n", name, len, start, erasesize);
return 0;
error:
@ -298,7 +314,7 @@ static int phram_param_call(const char *val, const struct kernel_param *kp)
}
module_param_call(phram, phram_param_call, NULL, NULL, 0200);
MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>[,<erasesize>]\"");
static int __init init_phram(void)