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ppc4xx fix unstable 440EPx bootstrap options

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440EPx fixed bootstrap options A, B, D, and E sets PLL FWDVA to a value = 1.
This results in the PLLOUTB being greater than the CPU clock frequency
resulting unstable 440EPx operation resulting in various software hang
conditions.

This patch reprograms the FWDVA satisfying the requirement of setting FWDVB
to a value greater than 1 while using one of the four deafult bootstrap options.

Signed-off-by: Rupjyoti Sarmah <rsarmah@amcc.com>
Acked-by : Victor Gallardo <vgallardo@appliedmicro.com>
Signed-off-by: Stefan Roese <sr@denx.de>
This commit is contained in:
Rupjyoti Sarmah 2010-03-24 16:52:02 +05:30 committed by Stefan Roese
parent 7027d5622d
commit c550afada5
2 changed files with 66 additions and 5 deletions
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65
cpu/ppc4xx/cpu_init.c
View file

@ -111,17 +111,72 @@ void reconfigure_pll(u32 new_cpu_freq)
mtcpr(CPR0_SPCID, reg);
reset_needed = 1;
}
}
/* Set reload inhibit so configuration will persist across
* processor resets */
/* Get current value of FWDVA.*/
mfcpr(CPR0_PLLD, reg);
temp = (reg & PLLD_FWDVA_MASK) >> 16;
/*
* Check to see if FWDVA has been set to value of 1. if it has we must
* modify it.
*/
if (temp == 1) {
mfcpr(CPR0_PLLD, reg);
/* Get current value of fbdv. */
temp = (reg & PLLD_FBDV_MASK) >> 24;
fbdv = temp ? temp : 32;
/* Get current value of lfbdv. */
temp = (reg & PLLD_LFBDV_MASK);
lfbdv = temp ? temp : 64;
/*
* Load register that contains current boot strapping option.
*/
mfcpr(CPR0_ICFG, reg);
/* Shift strapping option into low 3 bits.*/
reg = (reg >> 28);
if ((reg == BOOT_STRAP_OPTION_A) || (reg == BOOT_STRAP_OPTION_B) ||
(reg == BOOT_STRAP_OPTION_D) || (reg == BOOT_STRAP_OPTION_E)) {
/*
* Get current value of FWDVA. Assign current FWDVA to
* new FWDVB.
*/
mfcpr(CPR0_PLLD, reg);
target_fwdvb = (reg & PLLD_FWDVA_MASK) >> 16;
fwdvb = target_fwdvb ? target_fwdvb : 8;
/*
* Get current value of FWDVB. Assign current FWDVB to
* new FWDVA.
*/
target_fwdva = (reg & PLLD_FWDVB_MASK) >> 8;
fwdva = target_fwdva ? target_fwdva : 16;
/*
* Update CPR0_PLLD with switched FWDVA and FWDVB.
*/
reg &= ~(PLLD_FWDVA_MASK | PLLD_FWDVB_MASK |
PLLD_FBDV_MASK | PLLD_LFBDV_MASK);
reg |= ((fwdva == 16 ? 0 : fwdva) << 16) |
((fwdvb == 8 ? 0 : fwdvb) << 8) |
((fbdv == 32 ? 0 : fbdv) << 24) |
(lfbdv == 64 ? 0 : lfbdv);
mtcpr(CPR0_PLLD, reg);
/* Acknowledge that a reset is required. */
reset_needed = 1;
}
}
if (reset_needed) {
/*
* Set reload inhibit so configuration will persist across
* processor resets
*/
mfcpr(CPR0_ICFG, reg);
reg &= ~CPR0_ICFG_RLI_MASK;
reg |= 1 << 31;
mtcpr(CPR0_ICFG, reg);
}
/* Reset processor if configuration changed */
if (reset_needed) {
/* Reset processor if configuration changed */
__asm__ __volatile__ ("sync; isync");
mtspr(SPRN_DBCR0, 0x20000000);
}

6
include/ppc440.h
View file

@ -68,6 +68,12 @@
#define CPR0_SPCID 0x0120
#define CPR0_ICFG 0x0140
/* 440EPX boot strap options */
#define BOOT_STRAP_OPTION_A 0x00000000
#define BOOT_STRAP_OPTION_B 0x00000001
#define BOOT_STRAP_OPTION_D 0x00000003
#define BOOT_STRAP_OPTION_E 0x00000004
/* 440gx sdr register definations */
#define SDR0_SDSTP0 0x0020 /* */
#define SDR0_SDSTP1 0x0021 /* */