powerpc/8xxx: Add hwconfig APIs to address early parsing used by DDR init

There are several users of the hwconfig APIs (8xxx DDR) before we have
the environment properly setup.  This causes issues because of the
numerous ways the environment might be accessed because of the
non-volatile memory it might be stored in.  Additionally the access
might be so early that memory isn't even properly setup for us.

Towards resolving these issues we provide versions of all the hwconfig
APIs that can be passed in a buffer to parse and leave it to the caller
to determine how to allocate and populate the buffer.

We use the _f naming convention for these new APIs even though they are
perfectly useable after relocation and the environment being ready.

We also now warn if the non-f APIs are called before the environment is
ready to allow users to address the issues.

Finally, we convert the 8xxx DDR code to utilize the new APIs to
hopefully address the issue once and for all.  We have the 8xxx DDR code
create a buffer on the stack and populate it via getenv_f().

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Wolfgang Denk <wd@denx.de>

1 files changed, 59 insertions, 19 deletions

diff --git a/arch/powerpc/cpu/mpc8xxx/ddr/options.c b/arch/powerpc/cpu/mpc8xxx/ddr/options.c
index c641e85068..0e7097babb 100644
--- a/arch/powerpc/cpu/mpc8xxx/ddr/options.c
+++ b/arch/powerpc/cpu/mpc8xxx/ddr/options.c
@@ -13,6 +13,14 @@
 
 #include "ddr.h"
 
+/*
+ * Use our own stack based buffer before relocation to allow accessing longer
+ * hwconfig strings that might be in the environment before we've relocated.
+ * This is pretty fragile on both the use of stack and if the buffer is big
+ * enough. However we will get a warning from getenv_f for the later.
+ */
+#define HWCONFIG_BUFFER_SIZE	128
+
 /* Board-specific functions defined in each board's ddr.c */
 extern void fsl_ddr_board_options(memctl_options_t *popts,
 		dimm_params_t *pdimm,
@@ -24,6 +32,15 @@ unsigned int populate_memctl_options(int all_DIMMs_registered,
 			unsigned int ctrl_num)
 {
 	unsigned int i;
+	char buffer[HWCONFIG_BUFFER_SIZE];
+	char *buf = NULL;
+
+	/*
+	 * Extract hwconfig from environment since we have not properly setup
+	 * the environment but need it for ddr config params
+	 */
+	if (getenv_f("hwconfig", buffer, sizeof(buffer)) > 0)
+		buf = buffer;
 
 	/* Chip select options. */
 
@@ -221,7 +238,7 @@ unsigned int populate_memctl_options(int all_DIMMs_registered,
 	 * should be a subset of the requested configuration.
 	 */
 #if (CONFIG_NUM_DDR_CONTROLLERS > 1)
-	if (hwconfig_sub("fsl_ddr", "ctlr_intlv")) {
+	if (hwconfig_sub_f("fsl_ddr", "ctlr_intlv", buf)) {
 		if (pdimm[0].n_ranks == 0) {
 			printf("There is no rank on CS0 for controller %d. Because only"
 				" rank on CS0 and ranks chip-select interleaved with CS0"
@@ -234,19 +251,25 @@ unsigned int populate_memctl_options(int all_DIMMs_registered,
 			 * test null first. if CONFIG_HWCONFIG is not defined
 			 * hwconfig_arg_cmp returns non-zero
 			 */
-			if (hwconfig_subarg_cmp("fsl_ddr", "ctlr_intlv", "null")) {
+			if (hwconfig_subarg_cmp_f("fsl_ddr", "ctlr_intlv",
+						    "null", buf)) {
 				popts->memctl_interleaving = 0;
 				debug("memory controller interleaving disabled.\n");
-			} else if (hwconfig_subarg_cmp("fsl_ddr", "ctlr_intlv", "cacheline"))
+			} else if (hwconfig_subarg_cmp_f("fsl_ddr",
+							 "ctlr_intlv",
+							 "cacheline", buf))
 				popts->memctl_interleaving_mode =
 					FSL_DDR_CACHE_LINE_INTERLEAVING;
-			else if (hwconfig_subarg_cmp("fsl_ddr", "ctlr_intlv", "page"))
+			else if (hwconfig_subarg_cmp_f("fsl_ddr", "ctlr_intlv",
+						       "page", buf))
 				popts->memctl_interleaving_mode =
 					FSL_DDR_PAGE_INTERLEAVING;
-			else if (hwconfig_subarg_cmp("fsl_ddr", "ctlr_intlv", "bank"))
+			else if (hwconfig_subarg_cmp_f("fsl_ddr", "ctlr_intlv",
+						       "bank", buf))
 				popts->memctl_interleaving_mode =
 					FSL_DDR_BANK_INTERLEAVING;
-			else if (hwconfig_subarg_cmp("fsl_ddr", "ctlr_intlv", "superbank"))
+			else if (hwconfig_subarg_cmp_f("fsl_ddr", "ctlr_intlv",
+						       "superbank", buf))
 				popts->memctl_interleaving_mode =
 					FSL_DDR_SUPERBANK_INTERLEAVING;
 			else {
@@ -256,19 +279,24 @@ unsigned int populate_memctl_options(int all_DIMMs_registered,
 		}
 	}
 #endif
-	if ((hwconfig_sub("fsl_ddr", "bank_intlv")) &&
+	if ((hwconfig_sub_f("fsl_ddr", "bank_intlv", buf)) &&
 		(CONFIG_CHIP_SELECTS_PER_CTRL > 1)) {
 		/* test null first. if CONFIG_HWCONFIG is not defined,
-		 * hwconfig_arg_cmp returns non-zero */
-		if (hwconfig_subarg_cmp("fsl_ddr", "bank_intlv", "null"))
+		 * hwconfig_subarg_cmp_f returns non-zero */
+		if (hwconfig_subarg_cmp_f("fsl_ddr", "bank_intlv",
+					    "null", buf))
 			debug("bank interleaving disabled.\n");
-		else if (hwconfig_subarg_cmp("fsl_ddr", "bank_intlv", "cs0_cs1"))
+		else if (hwconfig_subarg_cmp_f("fsl_ddr", "bank_intlv",
+						 "cs0_cs1", buf))
 			popts->ba_intlv_ctl = FSL_DDR_CS0_CS1;
-		else if (hwconfig_subarg_cmp("fsl_ddr", "bank_intlv", "cs2_cs3"))
+		else if (hwconfig_subarg_cmp_f("fsl_ddr", "bank_intlv",
+						 "cs2_cs3", buf))
 			popts->ba_intlv_ctl = FSL_DDR_CS2_CS3;
-		else if (hwconfig_subarg_cmp("fsl_ddr", "bank_intlv", "cs0_cs1_and_cs2_cs3"))
+		else if (hwconfig_subarg_cmp_f("fsl_ddr", "bank_intlv",
+						 "cs0_cs1_and_cs2_cs3", buf))
 			popts->ba_intlv_ctl = FSL_DDR_CS0_CS1_AND_CS2_CS3;
-		else if (hwconfig_subarg_cmp("fsl_ddr", "bank_intlv", "cs0_cs1_cs2_cs3"))
+		else if (hwconfig_subarg_cmp_f("fsl_ddr", "bank_intlv",
+						 "cs0_cs1_cs2_cs3", buf))
 			popts->ba_intlv_ctl = FSL_DDR_CS0_CS1_CS2_CS3;
 		else
 			printf("hwconfig has unrecognized parameter for bank_intlv.\n");
@@ -342,10 +370,11 @@ unsigned int populate_memctl_options(int all_DIMMs_registered,
 		}
 	}
 
-	if (hwconfig_sub("fsl_ddr", "addr_hash")) {
-		if (hwconfig_subarg_cmp("fsl_ddr", "addr_hash", "null"))
+	if (hwconfig_sub_f("fsl_ddr", "addr_hash", buf)) {
+		if (hwconfig_subarg_cmp_f("fsl_ddr", "addr_hash", "null", buf))
 			popts->addr_hash = 0;
-		else if (hwconfig_subarg_cmp("fsl_ddr", "addr_hash", "true"))
+		else if (hwconfig_subarg_cmp_f("fsl_ddr", "addr_hash",
+					       "true", buf))
 			popts->addr_hash = 1;
 	}
 
@@ -393,11 +422,22 @@ int fsl_use_spd(void)
 	int use_spd = 0;
 
 #ifdef CONFIG_DDR_SPD
+	char buffer[HWCONFIG_BUFFER_SIZE];
+	char *buf = NULL;
+
+	/*
+	 * Extract hwconfig from environment since we have not properly setup
+	 * the environment but need it for ddr config params
+	 */
+	if (getenv_f("hwconfig", buffer, sizeof(buffer)) > 0)
+		buf = buffer;
+
 	/* if hwconfig is not enabled, or "sdram" is not defined, use spd */
-	if (hwconfig_sub("fsl_ddr", "sdram")) {
-		if (hwconfig_subarg_cmp("fsl_ddr", "sdram", "spd"))
+	if (hwconfig_sub_f("fsl_ddr", "sdram", buf)) {
+		if (hwconfig_subarg_cmp_f("fsl_ddr", "sdram", "spd", buf))
 			use_spd = 1;
-		else if (hwconfig_subarg_cmp("fsl_ddr", "sdram", "fixed"))
+		else if (hwconfig_subarg_cmp_f("fsl_ddr", "sdram",
+					       "fixed", buf))
 			use_spd = 0;
 		else
 			use_spd = 1;