mtd: phram: Allow the user to set the erase page size.
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
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ffad560394
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@ -6,14 +6,14 @@
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* Usage:
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*
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* one commend line parameter per device, each in the form:
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* phram=<name>,<start>,<len>
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* phram=<name>,<start>,<len>[,<erasesize>]
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* <name> may be up to 63 characters.
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* <start> and <len> can be octal, decimal or hexadecimal. If followed
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* <start>, <len>, and <erasesize> can be octal, decimal or hexadecimal. If followed
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* by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
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* gigabytes.
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* gigabytes. <erasesize> is optional and defaults to PAGE_SIZE.
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*
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* Example:
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* phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
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* phram=swap,64Mi,128Mi phram=test,900Mi,1Mi,64Ki
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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@ -26,6 +26,7 @@
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#include <linux/moduleparam.h>
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#include <linux/slab.h>
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#include <linux/mtd/mtd.h>
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#include <asm/div64.h>
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struct phram_mtd_list {
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struct mtd_info mtd;
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@ -88,7 +89,7 @@ static void unregister_devices(void)
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}
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}
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static int register_device(char *name, phys_addr_t start, size_t len)
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static int register_device(char *name, phys_addr_t start, size_t len, uint32_t erasesize)
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{
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struct phram_mtd_list *new;
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int ret = -ENOMEM;
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@ -115,7 +116,7 @@ static int register_device(char *name, phys_addr_t start, size_t len)
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new->mtd._write = phram_write;
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new->mtd.owner = THIS_MODULE;
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new->mtd.type = MTD_RAM;
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new->mtd.erasesize = PAGE_SIZE;
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new->mtd.erasesize = erasesize;
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new->mtd.writesize = 1;
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ret = -EAGAIN;
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@ -204,22 +205,23 @@ static inline void kill_final_newline(char *str)
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static int phram_init_called;
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/*
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* This shall contain the module parameter if any. It is of the form:
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* - phram=<device>,<address>,<size> for module case
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* - phram.phram=<device>,<address>,<size> for built-in case
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* We leave 64 bytes for the device name, 20 for the address and 20 for the
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* size.
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* Example: phram.phram=rootfs,0xa0000000,512Mi
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* - phram=<device>,<address>,<size>[,<erasesize>] for module case
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* - phram.phram=<device>,<address>,<size>[,<erasesize>] for built-in case
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* We leave 64 bytes for the device name, 20 for the address , 20 for the
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* size and 20 for the erasesize.
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* Example: phram.phram=rootfs,0xa0000000,512Mi,65536
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*/
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static char phram_paramline[64 + 20 + 20];
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static char phram_paramline[64 + 20 + 20 + 20];
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#endif
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static int phram_setup(const char *val)
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{
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char buf[64 + 20 + 20], *str = buf;
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char *token[3];
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char buf[64 + 20 + 20 + 20], *str = buf;
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char *token[4];
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char *name;
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uint64_t start;
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uint64_t len;
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uint64_t erasesize = PAGE_SIZE;
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int i, ret;
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if (strnlen(val, sizeof(buf)) >= sizeof(buf))
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@ -228,7 +230,7 @@ static int phram_setup(const char *val)
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strcpy(str, val);
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kill_final_newline(str);
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for (i = 0; i < 3; i++)
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for (i = 0; i < 4; i++)
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token[i] = strsep(&str, ",");
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if (str)
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@ -253,11 +255,25 @@ static int phram_setup(const char *val)
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goto error;
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}
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ret = register_device(name, start, len);
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if (token[3]) {
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ret = parse_num64(&erasesize, token[3]);
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if (ret) {
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parse_err("illegal erasesize\n");
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goto error;
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}
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}
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if (len == 0 || erasesize == 0 || erasesize > len
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|| erasesize > UINT_MAX || do_div(len, (uint32_t)erasesize) != 0) {
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parse_err("illegal erasesize or len\n");
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goto error;
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}
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ret = register_device(name, start, len, (uint32_t)erasesize);
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if (ret)
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goto error;
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pr_info("%s device: %#llx at %#llx\n", name, len, start);
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pr_info("%s device: %#llx at %#llx for erasesize %#llx\n", name, len, start, erasesize);
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return 0;
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error:
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@ -298,7 +314,7 @@ static int phram_param_call(const char *val, const struct kernel_param *kp)
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}
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module_param_call(phram, phram_param_call, NULL, NULL, 0200);
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MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
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MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>[,<erasesize>]\"");
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static int __init init_phram(void)
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