[Skiboot] [PATCH 5/5] external/pflash: Make MTD accesses the default

[Cyril Bur]

Now that BMC and host kernel mtd drivers exist and have matured we
should use them by default.

This is especially important since we seem to be telling everyone to use
pflash.

Signed-off-by: Cyril Bur <cyril.bur at au1.ibm.com>
---
This change is going through testing now. There are still some erasing
corner cases that will need to be resolved. The kernel seems happy to
use 64K blocks but both the ffs layout and current pflash are very 4K
centric, there may be teething issues.


 external/pflash/pflash.c | 44 ++++++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

diff --git a/external/pflash/pflash.c b/external/pflash/pflash.c
index 608220f..2ae246a 100644
--- a/external/pflash/pflash.c
+++ b/external/pflash/pflash.c
@@ -459,10 +459,13 @@ static void print_help(const char *pname)
 	printf("\t\tDon't ask for confirmation before erasing or flashing\n\n");
 	printf("\t-d, --dummy\n");
 	printf("\t\tDon't write to flash\n\n");
-	printf("\t-m, --mtd\n");
-	printf("\t\tAvoid accessing the flash directly if the BMC supports it.\n");
-	printf("\t\tThis will access the flash through the kernel MTD layer and\n");
-	printf("\t\tnot the flash directly\n");
+	printf("\t--direct\n");
+	printf("\t\tBypass all safety provided to you by the kernel driver\n");
+	printf("\t\tand use the flash driver built into pflash.\n");
+	printf("\t\tIf you are reading this sentence then this flag\n");
+	printf("\t\tis not what you want! This feature is not supported,\n");
+	printf("\t\tit can and likely will result in a bricked\n");
+	printf("\t\tmachine\n\n");
 	printf("\t-b, --bmc\n");
 	printf("\t\tTarget BMC flash instead of host flash.\n");
 	printf("\t\tNote: This carries a high chance of bricking your BMC if you\n");
@@ -533,7 +536,7 @@ int main(int argc, char *argv[])
 	bool show_help = false, show_version = false;
 	bool no_action = false, tune = false;
 	char *write_file = NULL, *read_file = NULL, *part_name = NULL;
-	bool ffs_toc_seen = false, mtd = false;
+	bool ffs_toc_seen = false, direct = false;
 	int rc;
 	const char *flashfilename = NULL;
 
@@ -543,7 +546,7 @@ int main(int argc, char *argv[])
 			{"size",	required_argument,	NULL,	's'},
 			{"partition",	required_argument,	NULL,	'P'},
 			{"bmc",		no_argument,		NULL,	'b'},
-			{"mtd",		no_argument,		NULL,	'm'},
+			{"direct",	no_argument,		NULL,	'D'},
 			{"enable-4B",	no_argument,		NULL,	'4'},
 			{"disable-4B",	no_argument,		NULL,	'3'},
 			{"read",	required_argument,	NULL,	'r'},
@@ -565,7 +568,7 @@ int main(int argc, char *argv[])
 		};
 		int c, oidx = 0;
 
-		c = getopt_long(argc, argv, "+:a:s:P:r:43Eemp:fdihvbtgS:T:cF:",
+		c = getopt_long(argc, argv, "+:a:s:P:r:43Eep:fdihvbtgS:T:cF:",
 				long_opts, &oidx);
 		if (c == -1)
 			break;
@@ -595,8 +598,8 @@ int main(int argc, char *argv[])
 		case 'e':
 			erase = true;
 			break;
-		case 'm':
-			mtd = true;
+		case 'D':
+			direct = true;
 			break;
 		case 'p':
 			program = true;
@@ -748,8 +751,8 @@ int main(int argc, char *argv[])
 		exit(1);
 	}
 
-	if (flashfilename && mtd) {
-		fprintf(stderr, "Filename or mtd access but not both\n");
+	if (flashfilename && direct) {
+		fprintf(stderr, "Filename or direct access but not both\n");
 		exit(1);
 	}
 
@@ -765,22 +768,15 @@ int main(int argc, char *argv[])
 		write_size = stbuf.st_size;
 	}
 
-	if (bmc_flash) {
-		/*
-		 * Try to see if we can access BMC flash on this arch at all...
-		 * even if what we really want to do is use MTD.
-		 * This helps give a more meaningful error messages.
-		 */
-
-		if (arch_flash_access(NULL, BMC_DIRECT) == ACCESS_INVAL) {
-			fprintf(stderr, "Can't access BMC flash on this architecture\n");
+	if (direct) {
+		if (arch_flash_access(NULL, bmc_flash ? BMC_DIRECT : PNOR_DIRECT) == ACCESS_INVAL) {
+			fprintf(stderr, "Can't access %s flash directly on this architecture\n",
+			        bmc_flash ? "BMC" : "PNOR");
 			exit(1);
 		}
-	}
-
-	if (mtd) {
+	} else if (!flashfilename) {
 		if (arch_flash_access(NULL, bmc_flash ? BMC_MTD : PNOR_MTD) == ACCESS_INVAL) {
-			fprintf(stderr, "Can't access %s flash through MTD on this architecture\n",
+			fprintf(stderr, "Can't access %s flash through MTD on this system\n",
 			        bmc_flash ? "BMC" : "PNOR");
 			exit(1);
 		}
-- 
2.10.0