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> Reviewed-by: Joern Engel <jo...@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 <zhongguoh...@huawei.com> --- drivers/mtd/devices/phram.c | 52 +++++++++++++++++++++++++++++---------------- 1 file changed, 34 insertions(+), 18 deletions(-) diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c index 087b5e86d1bf..1729b94b2abf 100644 --- a/drivers/mtd/devices/phram.c +++ b/drivers/mtd/devices/phram.c @@ -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) -- 2.12.3
