zephyr: switch to platform/ec printf format implementation

Prior to this change, the cprints and cprintf shim implementations
used Zephyr's printk to do the output formatting.

Our EC code has some custom printf specifiers not supported by
Zephyr's printk.  We've already attempted to send some of our custom
specifiers upstream, but upstream does not want them:

https://github.com/zephyrproject-rtos/zephyr/pull/28882

The logical thing to do would be to bring in the vfnprintf function
from our EC to the Zephyr build, and use that to do the output
formatting instead.  That's what this CL does.

The binary cost of brining in this second printf implementation
appears to be minimal (952 bytes on volteer).

BUG=b:177065615
BRANCH=none
TEST=on posix-ec and volteer, run gettime and observe output no longer
     contains %.6lld, but instead the correct system time

Signed-off-by: Jack Rosenthal <jrosenth@chromium.org>
Change-Id: I53cd4edf129223c12a2c5e7d0519623a8d07a328
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2618575

6 files changed, 69 insertions, 4 deletions

diff --git a/common/printf.c b/common/printf.c
index f876a1da19..039a83a92f 100644
--- a/common/printf.c
+++ b/common/printf.c
@@ -275,7 +275,9 @@ int vfnprintf(int (*addchar)(void *context, int c), void *context,
 					continue;
 				/* %pT - print a timestamp. */
 				if (ptrspec == 'T' &&
-				    !IS_ENABLED(NO_UINT64_SUPPORT)) {
+				    !IS_ENABLED(NO_UINT64_SUPPORT) &&
+				    (!IS_ENABLED(CONFIG_ZEPHYR) ||
+				     IS_ENABLED(CONFIG_PLATFORM_EC_TIMER))) {
 					flags |= PF_64BIT;
 					if (ptrval == PRINTF_TIMESTAMP_NOW)
 						v = get_time().val;
@@ -461,6 +463,12 @@ int vfnprintf(int (*addchar)(void *context, int c), void *context,
 	return EC_SUCCESS;
 }
 
+/*
+ * These symbols are already defined by the Zephyr OS kernel, and we
+ * don't want to use the EC implementation.
+ */
+#ifndef CONFIG_ZEPHYR
+
 /* Context for snprintf() */
 struct snprintf_context {
 	char *str;
@@ -516,3 +524,5 @@ int vsnprintf(char *str, int size, const char *format, va_list args)
 
 	return (rv == EC_SUCCESS) ? (ctx.str - str) : -rv;
 }
+
+#endif /* !CONFIG_ZEPHYR */
diff --git a/zephyr/CMakeLists.txt b/zephyr/CMakeLists.txt
index 68f7382cc6..28620657d4 100644
--- a/zephyr/CMakeLists.txt
+++ b/zephyr/CMakeLists.txt
@@ -40,6 +40,7 @@ add_subdirectory_ifdef(CONFIG_PLATFORM_EC "shim")
 # supported by all boards and emulators (including unit tests) using the shim
 # layer.
 zephyr_sources_ifdef(CONFIG_PLATFORM_EC         "${PLATFORM_EC}/common/base32.c"
+                                                "${PLATFORM_EC}/common/printf.c"
                                                 "${PLATFORM_EC}/common/queue.c"
                                                 "${PLATFORM_EC}/common/shared_mem.c")
 
diff --git a/zephyr/shim/src/console.c b/zephyr/shim/src/console.c
index f59bda2f63..f07b56cf2f 100644
--- a/zephyr/shim/src/console.c
+++ b/zephyr/shim/src/console.c
@@ -10,12 +10,19 @@
 #include <zephyr.h>
 
 #include "console.h"
+#include "printf.h"
 
 int cputs(enum console_channel channel, const char *str)
 {
 	return cprintf(channel, "%s", str);
 }
 
+static int printk_putchar(void *context, int c)
+{
+	printk("%c", c);
+	return 0;
+}
+
 static void console_vprintf(enum console_channel channel, const char *format,
 			    va_list args)
 {
@@ -27,7 +34,7 @@ static void console_vprintf(enum console_channel channel, const char *format,
 	 * use shell_ print functions instead of printk function as they could
 	 * be on different uarts (they are not for Chrome OS Apps though).
 	 */
-	vprintk(format, args);
+	vfnprintf(printk_putchar, NULL, format, args);
 }
 
 __attribute__((__format__(__printf__, 2, 3))) int
@@ -46,7 +53,7 @@ cprints(enum console_channel channel, const char *format, ...)
 {
 	va_list args;
 
-	cprintf(channel, "[%lld ", k_uptime_get());
+	cprintf(channel, "[%pT ", PRINTF_TIMESTAMP_NOW);
 	va_start(args, format);
 	console_vprintf(channel, format, args);
 	va_end(args);
diff --git a/zephyr/shim/src/util.c b/zephyr/shim/src/util.c
index 3181fccb95..5a7131b23a 100644
--- a/zephyr/shim/src/util.c
+++ b/zephyr/shim/src/util.c
@@ -161,3 +161,47 @@ int parse_offset_size(int argc, char **argv, int shift, int *offset, int *size)
 
 	return EC_SUCCESS;
 }
+
+int uint64divmod(uint64_t *n, int d)
+{
+	uint64_t q = 0, mask;
+	int r = 0;
+
+	/* Divide-by-zero returns zero */
+	if (!d) {
+		*n = 0;
+		return 0;
+	}
+
+	/* Common powers of 2 = simple shifts */
+	if (d == 2) {
+		r = *n & 1;
+		*n >>= 1;
+		return r;
+	} else if (d == 16) {
+		r = *n & 0xf;
+		*n >>= 4;
+		return r;
+	}
+
+	/* If v fits in 32-bit, we're done. */
+	if (*n <= 0xffffffff) {
+		uint32_t v32 = *n;
+		r = v32 % d;
+		*n = v32 / d;
+		return r;
+	}
+
+	/* Otherwise do integer division the slow way. */
+	for (mask = (1ULL << 63); mask; mask >>= 1) {
+		r <<= 1;
+		if (*n & mask)
+			r |= 1;
+		if (r >= d) {
+			r -= d;
+			q |= mask;
+		}
+	}
+	*n = q;
+	return r;
+}
diff --git a/zephyr/test/hooks/CMakeLists.txt b/zephyr/test/hooks/CMakeLists.txt
index e44ebfe674..2236963762 100644
--- a/zephyr/test/hooks/CMakeLists.txt
+++ b/zephyr/test/hooks/CMakeLists.txt
@@ -23,5 +23,7 @@ zephyr_include_directories(
 
 # Include test file, test under test and console dependency
 target_sources(app PRIVATE hooks.c)
+target_sources(app PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/../../../common/printf.c")
 target_sources(app PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/../../shim/src/hooks.c")
 target_sources(app PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/../../shim/src/console.c")
+target_sources(app PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/../../shim/src/util.c")
diff --git a/zephyr/test/i2c/CMakeLists.txt b/zephyr/test/i2c/CMakeLists.txt
index 94c5deb8cc..4edbfb9006 100644
--- a/zephyr/test/i2c/CMakeLists.txt
+++ b/zephyr/test/i2c/CMakeLists.txt
@@ -25,4 +25,5 @@ target_sources(app PRIVATE
 	"${PLATFORM_EC}/zephyr/shim/src/console.c"
 	"${PLATFORM_EC}/zephyr/shim/src/i2c.c"
 	"${PLATFORM_EC}/zephyr/shim/src/util.c"
-	"${PLATFORM_EC}/common/i2c_controller.c")
+	"${PLATFORM_EC}/common/i2c_controller.c"
+	"${PLATFORM_EC}/common/printf.c")