From: Patrick O'Grady <patr...@baymotion.com> 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 <patr...@baymotion.com> --- diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c index 67823de..5eee2a6 100644 --- a/drivers/mtd/devices/phram.c +++ b/drivers/mtd/devices/phram.c @@ -5,14 +5,15 @@ * 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 - * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or - * gigabytes. + * <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. <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 @@ -94,7 +95,8 @@ static void unregister_devices(void) } } -static int register_device(char *name, unsigned long start, unsigned long len) +static int register_device(char *name, unsigned long start, + unsigned long len, unsigned long erasesize) { struct phram_mtd_list *new; int ret = -ENOMEM; @@ -121,7 +123,7 @@ static int register_device(char *name, unsigned long start, unsigned long 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; @@ -207,21 +209,22 @@ static inline void kill_final_newline(char *str) /* * 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, 12 for the address and 12 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, 12 for the address, 12 for the + * size, and 12 for the erasesize. + * Example: phram.phram=rootfs,0xa0000000,512Mi,65536 */ static __initdata char phram_paramline[64+12+12]; static int __init phram_setup(const char *val) { - char buf[64+12+12], *str = buf; + char buf[64+12+12+12], *str = buf; char *token[3]; char *name; uint32_t start; uint32_t len; + uint32_t erasesize = PAGE_SIZE ; int i, ret; if (strnlen(val, sizeof(buf)) >= sizeof(buf)) @@ -230,7 +233,7 @@ static int __init 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) @@ -255,7 +258,15 @@ static int __init phram_setup(const char *val) parse_err("illegal device length\n"); } - ret = register_device(name, start, len); + if (token[3]) { + ret = parse_num32(&erasesize, token[3]); + if (ret) { + kfree(name); + parse_err("illegal erase size\n"); + } + } + + ret = register_device(name, start, len, erasesize); if (!ret) pr_info("%s device: %#x at %#x\n", name, len, start); else @@ -278,7 +289,7 @@ static int __init phram_param_call(const char *val, struct kernel_param *kp) } module_param_call(phram, phram_param_call, NULL, NULL, 000); -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) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/