From ce4fecf1fe1518131ff80eebf412de0080fea049 Mon Sep 17 00:00:00 2001 From: Pantelis Antoniou Date: Wed, 21 Jan 2015 19:06:14 +0200 Subject: vsprintf: Add %p extension "%pOF" for device tree 90% of the usage of device node's full_name is printing it out in a kernel message. However, storing the full path for every node is wasteful and redundant. With a custom format specifier, we can generate the full path at run-time and eventually remove the full path from every node. For instance typical use is: pr_info("Frobbing node %s\n", node->full_name); Which can be written now as: pr_info("Frobbing node %pOF\n", node); '%pO' is the base specifier to represent kobjects with '%pOF' representing struct device_node. Currently, struct device_node is the only supported type of kobject. More fine-grained control of formatting includes printing the name, flags, path-spec name and others, explained in the documentation entry. Originally written by Pantelis, but pretty much rewrote the core function using existing string/number functions. The 2 passes were unnecessary and have been removed. Also, updated the checkpatch.pl check. The unittest code was written by Grant Likely. Signed-off-by: Pantelis Antoniou Acked-by: Joe Perches Signed-off-by: Rob Herring --- lib/vsprintf.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) (limited to 'lib/vsprintf.c') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 2d41de3f98a1..ff8f1269f301 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #ifdef CONFIG_BLOCK #include @@ -1470,6 +1471,126 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt) return format_flags(buf, end, flags, names); } +static const char *device_node_name_for_depth(const struct device_node *np, int depth) +{ + for ( ; np && depth; depth--) + np = np->parent; + + return kbasename(np->full_name); +} + +static noinline_for_stack +char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end) +{ + int depth; + const struct device_node *parent = np->parent; + static const struct printf_spec strspec = { + .field_width = -1, + .precision = -1, + }; + + /* special case for root node */ + if (!parent) + return string(buf, end, "/", strspec); + + for (depth = 0; parent->parent; depth++) + parent = parent->parent; + + for ( ; depth >= 0; depth--) { + buf = string(buf, end, "/", strspec); + buf = string(buf, end, device_node_name_for_depth(np, depth), + strspec); + } + return buf; +} + +static noinline_for_stack +char *device_node_string(char *buf, char *end, struct device_node *dn, + struct printf_spec spec, const char *fmt) +{ + char tbuf[sizeof("xxxx") + 1]; + const char *p; + int ret; + char *buf_start = buf; + struct property *prop; + bool has_mult, pass; + static const struct printf_spec num_spec = { + .flags = SMALL, + .field_width = -1, + .precision = -1, + .base = 10, + }; + + struct printf_spec str_spec = spec; + str_spec.field_width = -1; + + if (!IS_ENABLED(CONFIG_OF)) + return string(buf, end, "(!OF)", spec); + + if ((unsigned long)dn < PAGE_SIZE) + return string(buf, end, "(null)", spec); + + /* simple case without anything any more format specifiers */ + fmt++; + if (fmt[0] == '\0' || strcspn(fmt,"fnpPFcC") > 0) + fmt = "f"; + + for (pass = false; strspn(fmt,"fnpPFcC"); fmt++, pass = true) { + if (pass) { + if (buf < end) + *buf = ':'; + buf++; + } + + switch (*fmt) { + case 'f': /* full_name */ + buf = device_node_gen_full_name(dn, buf, end); + break; + case 'n': /* name */ + buf = string(buf, end, dn->name, str_spec); + break; + case 'p': /* phandle */ + buf = number(buf, end, (unsigned int)dn->phandle, num_spec); + break; + case 'P': /* path-spec */ + p = kbasename(of_node_full_name(dn)); + if (!p[1]) + p = "/"; + buf = string(buf, end, p, str_spec); + break; + case 'F': /* flags */ + tbuf[0] = of_node_check_flag(dn, OF_DYNAMIC) ? 'D' : '-'; + tbuf[1] = of_node_check_flag(dn, OF_DETACHED) ? 'd' : '-'; + tbuf[2] = of_node_check_flag(dn, OF_POPULATED) ? 'P' : '-'; + tbuf[3] = of_node_check_flag(dn, OF_POPULATED_BUS) ? 'B' : '-'; + tbuf[4] = 0; + buf = string(buf, end, tbuf, str_spec); + break; + case 'c': /* major compatible string */ + ret = of_property_read_string(dn, "compatible", &p); + if (!ret) + buf = string(buf, end, p, str_spec); + break; + case 'C': /* full compatible string */ + has_mult = false; + of_property_for_each_string(dn, "compatible", prop, p) { + if (has_mult) + buf = string(buf, end, ",", str_spec); + buf = string(buf, end, "\"", str_spec); + buf = string(buf, end, p, str_spec); + buf = string(buf, end, "\"", str_spec); + + has_mult = true; + } + break; + default: + break; + } + } + + return widen_string(buf, buf - buf_start, end, spec); +} + int kptr_restrict __read_mostly; /* @@ -1566,6 +1687,16 @@ int kptr_restrict __read_mostly; * p page flags (see struct page) given as pointer to unsigned long * g gfp flags (GFP_* and __GFP_*) given as pointer to gfp_t * v vma flags (VM_*) given as pointer to unsigned long + * - 'O' For a kobject based struct. Must be one of the following: + * - 'OF[fnpPcCF]' For a device tree object + * Without any optional arguments prints the full_name + * f device node full_name + * n device node name + * p device node phandle + * P device node path spec (name + @unit) + * F device node flags + * c major compatible string + * C full compatible string * * ** Please update also Documentation/printk-formats.txt when making changes ** * @@ -1721,6 +1852,11 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'G': return flags_string(buf, end, ptr, fmt); + case 'O': + switch (fmt[1]) { + case 'F': + return device_node_string(buf, end, ptr, spec, fmt + 1); + } } spec.flags |= SMALL; if (spec.field_width == -1) { -- cgit v1.2.3-58-ga151