lib/vsprintf: Print time and date in human readable format via %pt

There are users which print time and date represented by content of
struct rtc_time in human readable format.

Instead of open coding that each time introduce %ptR[dt][r] specifier.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 37a54a6dd594..3add92329bae 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -30,6 +30,7 @@
 #include <linux/ioport.h>
 #include <linux/dcache.h>
 #include <linux/cred.h>
+#include <linux/rtc.h>
 #include <linux/uuid.h>
 #include <linux/of.h>
 #include <net/addrconf.h>
@@ -822,6 +823,20 @@ static const struct printf_spec default_dec_spec = {
         .precision = -1,
 };
 
+static const struct printf_spec default_dec02_spec = {
+        .base = 10,
+        .field_width = 2,
+        .precision = -1,
+        .flags = ZEROPAD,
+};
+
+static const struct printf_spec default_dec04_spec = {
+        .base = 10,
+        .field_width = 4,
+        .precision = -1,
+        .flags = ZEROPAD,
+};
+
 static noinline_for_stack
 char *resource_string(char *buf, char *end, struct resource *res,
                       struct printf_spec spec, const char *fmt)
@@ -1550,6 +1565,87 @@ char *address_val(char *buf, char *end, const void *addr, const char *fmt)
 }
 
 static noinline_for_stack
+char *date_str(char *buf, char *end, const struct rtc_time *tm, bool r)
+{
+        int year = tm->tm_year + (r ? 0 : 1900);
+        int mon = tm->tm_mon + (r ? 0 : 1);
+
+        buf = number(buf, end, year, default_dec04_spec);
+        if (buf < end)
+                *buf = '-';
+        buf++;
+
+        buf = number(buf, end, mon, default_dec02_spec);
+        if (buf < end)
+                *buf = '-';
+        buf++;
+
+        return number(buf, end, tm->tm_mday, default_dec02_spec);
+}
+
+static noinline_for_stack
+char *time_str(char *buf, char *end, const struct rtc_time *tm, bool r)
+{
+        buf = number(buf, end, tm->tm_hour, default_dec02_spec);
+        if (buf < end)
+                *buf = ':';
+        buf++;
+
+        buf = number(buf, end, tm->tm_min, default_dec02_spec);
+        if (buf < end)
+                *buf = ':';
+        buf++;
+
+        return number(buf, end, tm->tm_sec, default_dec02_spec);
+}
+
+static noinline_for_stack
+char *rtc_str(char *buf, char *end, const struct rtc_time *tm, const char *fmt)
+{
+        bool have_t = true, have_d = true;
+        bool raw = false;
+        int count = 2;
+
+        switch (fmt[count]) {
+        case 'd':
+                have_t = false;
+                count++;
+                break;
+        case 't':
+                have_d = false;
+                count++;
+                break;
+        }
+
+        raw = fmt[count] == 'r';
+
+        if (have_d)
+                buf = date_str(buf, end, tm, raw);
+        if (have_d && have_t) {
+                /* Respect ISO 8601 */
+                if (buf < end)
+                        *buf = 'T';
+                buf++;
+        }
+        if (have_t)
+                buf = time_str(buf, end, tm, raw);
+
+        return buf;
+}
+
+static noinline_for_stack
+char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec,
+                    const char *fmt)
+{
+        switch (fmt[1]) {
+        case 'R':
+                return rtc_str(buf, end, (const struct rtc_time *)ptr, fmt);
+        default:
+                return ptr_to_id(buf, end, ptr, spec);
+        }
+}
+
+static noinline_for_stack
 char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
             const char *fmt)
 {
@@ -1828,6 +1924,8 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
  * - 'd[234]' For a dentry name (optionally 2-4 last components)
  * - 'D[234]' Same as 'd' but for a struct file
  * - 'g' For block_device name (gendisk + partition number)
+ * - 't[R][dt][r]' For time and date as represented:
+ *      R    struct rtc_time
  * - 'C' For a clock, it prints the name (Common Clock Framework) or address
  *       (legacy clock framework) of the clock
  * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
@@ -1952,6 +2050,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
                 return address_val(buf, end, ptr, fmt);
         case 'd':
                 return dentry_name(buf, end, ptr, spec, fmt);
+        case 't':
+                return time_and_date(buf, end, ptr, spec, fmt);
         case 'C':
                 return clock(buf, end, ptr, spec, fmt);
         case 'D':