rm9200 lowevel_init: don't touch reserved/readonly registers

For some reason the AT91rm9200 lowlevel init writes to a bunch of
reserved or read-only addresses.  All the boards seem to define the
value-to-be-written values as zero ... but they shouldn't actually
be writing *anything* there.

No documented erratum justifies these accesses.  It looks like maybe
some pre-release BDI-2000 setup code has been carried along by cargo
cult programming since at least late 2004 (per GIT history).

Here's a patch disabling what seems to be bogosity.  Tested on a
csb337; there were no behavioral changes.

Signed-off-by: David Brownell <david-b@pacbell.net>
on RM9200ek
Tested-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

diff --git a/cpu/arm920t/at91rm9200/lowlevel_init.S b/cpu/arm920t/at91rm9200/lowlevel_init.S
index 0913284..d8bb960 100644 (file)
--- a/cpu/arm920t/at91rm9200/lowlevel_init.S
+++ b/cpu/arm920t/at91rm9200/lowlevel_init.S
@@ -81,6 +81,7 @@ LoopOsc:
        bne     0b
        /* delay - this is all done by guess */
        ldr     r0, =0x00010000
+       /* (vs reading PMC_SR for LOCKA, LOCKB ... or MOSCS earlier) */
 1:
        subs    r0, r0, #1
        bhi     1b
@@ -108,16 +109,6 @@ LoopOsc:
        .ltorg
 
 SMRDATA:
-       .word AT91C_MC_PUIA
-       .word CONFIG_SYS_MC_PUIA_VAL
-       .word AT91C_MC_PUP
-       .word CONFIG_SYS_MC_PUP_VAL
-       .word AT91C_MC_PUER
-       .word CONFIG_SYS_MC_PUER_VAL
-       .word AT91C_MC_ASR
-       .word CONFIG_SYS_MC_ASR_VAL
-       .word AT91C_MC_AASR
-       .word CONFIG_SYS_MC_AASR_VAL
        .word AT91C_EBI_CFGR
        .word CONFIG_SYS_EBI_CFGR_VAL
        .word AT91C_SMC_CSR0
@@ -128,8 +119,7 @@ SMRDATA:
        .word CONFIG_SYS_PLLBR_VAL
        .word AT91C_MCKR
        .word CONFIG_SYS_MCKR_VAL
-       /* SMRDATA is 80 bytes long */
-       /* here there's a delay of 100 */
+       /* here there's a delay */
 SMRDATA1:
        .word AT91C_PIOC_ASR
        .word CONFIG_SYS_PIOC_ASR_VAL

diff --git a/include/configs/at91rm9200dk.h b/include/configs/at91rm9200dk.h
index 2017b66..590c69a 100644 (file)
--- a/include/configs/at91rm9200dk.h
+++ b/include/configs/at91rm9200dk.h
@@ -45,11 +45,6 @@
 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 #define CONFIG_SYS_USE_MAIN_OSCILLATOR         1
 /* flash */
-#define CONFIG_SYS_MC_PUIA_VAL 0x00000000
-#define CONFIG_SYS_MC_PUP_VAL  0x00000000
-#define CONFIG_SYS_MC_PUER_VAL 0x00000000
-#define CONFIG_SYS_MC_ASR_VAL  0x00000000
-#define CONFIG_SYS_MC_AASR_VAL 0x00000000
 #define CONFIG_SYS_EBI_CFGR_VAL        0x00000000
 #define CONFIG_SYS_SMC_CSR0_VAL        0x00003284 /* 16bit, 2 TDF, 4 WS */
 

diff --git a/include/configs/at91rm9200ek.h b/include/configs/at91rm9200ek.h
index 58ec94a..b4f075e 100644 (file)
--- a/include/configs/at91rm9200ek.h
+++ b/include/configs/at91rm9200ek.h
@@ -56,11 +56,6 @@
 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 #define CONFIG_SYS_USE_MAIN_OSCILLATOR         1
 /* flash */
-#define CONFIG_SYS_MC_PUIA_VAL 0x00000000
-#define CONFIG_SYS_MC_PUP_VAL  0x00000000
-#define CONFIG_SYS_MC_PUER_VAL 0x00000000
-#define CONFIG_SYS_MC_ASR_VAL  0x00000000
-#define CONFIG_SYS_MC_AASR_VAL 0x00000000
 #define CONFIG_SYS_EBI_CFGR_VAL        0x00000000
 #define CONFIG_SYS_SMC_CSR0_VAL        0x00003284 /* 16bit, 2 TDF, 4 WS */
 

diff --git a/include/configs/cmc_pu2.h b/include/configs/cmc_pu2.h
index 80559bf..be478b2 100644 (file)
--- a/include/configs/cmc_pu2.h
+++ b/include/configs/cmc_pu2.h
@@ -44,11 +44,6 @@
 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 #define CONFIG_SYS_USE_MAIN_OSCILLATOR         1
 /* flash */
-#define CONFIG_SYS_MC_PUIA_VAL 0x00000000
-#define CONFIG_SYS_MC_PUP_VAL  0x00000000
-#define CONFIG_SYS_MC_PUER_VAL 0x00000000
-#define CONFIG_SYS_MC_ASR_VAL  0x00000000
-#define CONFIG_SYS_MC_AASR_VAL 0x00000000
 #define CONFIG_SYS_EBI_CFGR_VAL        0x00000000
 #define CONFIG_SYS_SMC_CSR0_VAL        0x100032ad /* 16bit, 2 TDF, 4 WS */
 

diff --git a/include/configs/csb637.h b/include/configs/csb637.h
index 7a57696..f4fd808 100644 (file)
--- a/include/configs/csb637.h
+++ b/include/configs/csb637.h
@@ -45,11 +45,6 @@
 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 #define CONFIG_SYS_USE_MAIN_OSCILLATOR         1
 /* flash */
-#define CONFIG_SYS_MC_PUIA_VAL 0x00000000
-#define CONFIG_SYS_MC_PUP_VAL  0x00000000
-#define CONFIG_SYS_MC_PUER_VAL 0x00000000
-#define CONFIG_SYS_MC_ASR_VAL  0x00000000
-#define CONFIG_SYS_MC_AASR_VAL 0x00000000
 #define CONFIG_SYS_EBI_CFGR_VAL        0x00000000
 #define CONFIG_SYS_SMC_CSR0_VAL        0x00003284 /* 16bit, 2 TDF, 4 WS */
 

diff --git a/include/configs/m501sk.h b/include/configs/m501sk.h
index 32a8194..5c06642 100644 (file)
--- a/include/configs/m501sk.h
+++ b/include/configs/m501sk.h
@@ -46,11 +46,6 @@
  */
 #define CONFIG_SYS_USE_MAIN_OSCILLATOR         1
 /* flash */
-#define CONFIG_SYS_MC_PUIA_VAL 0x00000000
-#define CONFIG_SYS_MC_PUP_VAL  0x00000000
-#define CONFIG_SYS_MC_PUER_VAL 0x00000000
-#define CONFIG_SYS_MC_ASR_VAL  0x00000000
-#define CONFIG_SYS_MC_AASR_VAL 0x00000000
 #define CONFIG_SYS_EBI_CFGR_VAL        0x00000000
 #define CONFIG_SYS_SMC_CSR0_VAL        0x00003284 /* 16bit, 2 TDF, 4 WS */
 

diff --git a/include/configs/mp2usb.h b/include/configs/mp2usb.h
index ac678d0..0c2ee60 100644 (file)
--- a/include/configs/mp2usb.h
+++ b/include/configs/mp2usb.h
@@ -49,11 +49,6 @@
 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 #define CONFIG_SYS_USE_MAIN_OSCILLATOR 1
 /* flash */
-#define CONFIG_SYS_MC_PUIA_VAL 0x00000000
-#define CONFIG_SYS_MC_PUP_VAL  0x00000000
-#define CONFIG_SYS_MC_PUER_VAL 0x00000000
-#define CONFIG_SYS_MC_ASR_VAL  0x00000000
-#define CONFIG_SYS_MC_AASR_VAL 0x00000000
 #define CONFIG_SYS_EBI_CFGR_VAL        0x00000000
 #define CONFIG_SYS_SMC_CSR0_VAL        0x00003084 /* 16bit, 2 TDF, 4 WS */