[PATCH v4] cmd: mem: add function for getting ram size for use in scripts

[Frank Wunderlich <linux@fw-web.de>]

From: Frank Wunderlich <frank-w@public-files.de>

Add a command for getting detected ram size with possibility to write
to environment variable.

example usage:

BPI-R4> msize
4294967296
BPI-R4> msize m
4096m
BPI-R4> msize g
4g
BPI-R4> msize g ramsize
BPI-R4> printenv ramsize
ramsize=4
BPI-R4>

board with 8GB ram:

BPI-R4> msize
8589934592
BPI-R4> msize m
8192m
BPI-R4> msize g
8g
BPI-R4> msize g ramsize
BPI-R4> printenv ramsize
ramsize=8
BPI-R4>

Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
---
v4: drop rounding to full MB/GB as it leads to wrong display
v3: add missing ifdefs
v2: add Kconfig entry
---
 cmd/Kconfig |  5 +++++
 cmd/mem.c   | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/cmd/Kconfig b/cmd/Kconfig
index 5c611fb3016e..b82b17195b7e 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -974,6 +974,11 @@ config CMD_RANDOM
 	help
 	  random - fill memory with random data
 
+config CMD_MEMSIZE
+	bool "memsize"
+	help
+	  Get RAM via command for use in scripts.
+
 config CMD_MEMTEST
 	bool "memtest"
 	help
diff --git a/cmd/mem.c b/cmd/mem.c
index d5d7ca2790bd..9dcfeacbbcc5 100644
--- a/cmd/mem.c
+++ b/cmd/mem.c
@@ -33,6 +33,7 @@
 #include <linux/compiler.h>
 #include <linux/ctype.h>
 #include <linux/delay.h>
+#include <linux/sizes.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -711,6 +712,29 @@ static int do_mem_loopw(struct cmd_tbl *cmdtp, int flag, int argc,
 }
 #endif /* CONFIG_LOOPW */
 
+#ifdef CONFIG_CMD_MEMSIZE
+static int do_mem_size(struct cmd_tbl *cmdtp, int flag, int argc,
+		       char *const argv[])
+{
+	u64 memsize = gd->ram_size;
+
+	if (argc > 1) {
+		if (!strcmp(argv[1], "m"))
+			memsize = memsize / SZ_1M;
+		else if (!strcmp(argv[1], "g"))
+			memsize = memsize / SZ_1G;
+		if (argc > 2)
+			env_set_ulong(argv[2], memsize);
+		else
+			printf("%lld%s\n", memsize, argv[1]);
+	} else {
+		printf("%lld\n", memsize);
+	}
+
+	return 0;
+}
+#endif /* CONFIG_CMD_MEMSIZE */
+
 #ifdef CONFIG_CMD_MEMTEST
 static ulong mem_test_alt(volatile ulong *buf, ulong start_addr, ulong end_addr,
 			  volatile ulong *dummy)
@@ -1404,6 +1428,14 @@ U_BOOT_CMD(
 );
 #endif /* CONFIG_LOOPW */
 
+#ifdef CONFIG_CMD_MEMSIZE
+U_BOOT_CMD(
+	msize,	3,	1,	do_mem_size,
+	"get detected ram size, optional set env variable with value",
+	"[m, g] [envvar]"
+);
+#endif /* CONFIG_CMD_MEMSIZE */
+
 #ifdef CONFIG_CMD_MEMTEST
 U_BOOT_CMD(
 	mtest,	5,	1,	do_mem_mtest,
-- 
2.43.0