From da57bddb827ff0da2eb8da33b7081ff56d9dea2d Mon Sep 17 00:00:00 2001 From: Justin Waters Date: Wed, 19 Dec 2012 11:13:24 -0500 Subject: vybrid: Fix hardware clock drift We must enable the external 32kHz oscillator in order to work around a known clock drift issue with the internal 32kHz oscillator. This fixes the Linux kernel system clock drift. Signed-off-by: Anthony Huereca Signed-off-by: Jiri Kotzian Signed-off-by: Justin Waters --- arch/arm/include/asm/arch-vybrid/scsc_regs.h | 55 ++++++++++++++++++++++++++++ board/freescale/vybrid/vybrid.c | 15 ++++++++ 2 files changed, 70 insertions(+) create mode 100644 arch/arm/include/asm/arch-vybrid/scsc_regs.h diff --git a/arch/arm/include/asm/arch-vybrid/scsc_regs.h b/arch/arm/include/asm/arch-vybrid/scsc_regs.h new file mode 100644 index 0000000000..db019835a0 --- /dev/null +++ b/arch/arm/include/asm/arch-vybrid/scsc_regs.h @@ -0,0 +1,55 @@ +/* + * Copyright 2012 Freescale Semiconductor, Inc. All Rights Reserved. + * Copyright 2012 Timesys Corporation All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + + +#ifndef __ARCH_ARM_MACH_VYBRID_SCSC_REGS_H__ +#define __ARCH_ARM_MACH_VYBRID_SCSC_REGS_H__ + +struct vybrid_scsc_reg { + u32 sicr_ctr; /* 0x0000 */ + u32 sosc_ctr; + u32 lfsr_ctr; +}; + +/* Define the bits in register sicr_ctr */ +#define VYBRID_SCSC_SICR_CTR_SIRC_DIV_MASK (0x7F << 8) +#define VYBRID_SCSC_SICR_CTR_SIRC_DIV_OFFSET 8 +#define VYBRID_SCSC_SICR_CTR_SIRC_SIRC_ON_FAIL (1 << 4) +#define VYBRID_SCSC_SICR_CTR_SIRC_SIRC_EN (1 << 0) + +/* Define the bits in register sosc_ctr */ +#define VYBRID_SCSC_SICR_CTR_SOSC_BYPASS (1 << 3) +#define VYBRID_SCSC_SICR_CTR_SOSC_EN (1 << 0) + +#define VYBRID_SCSC_LFSR_POLY_LFSR_MASK (0xFFFF << 16) +#define VYBRID_SCSC_LFSR_POLY_LFSR_OFFSET 16 +#define VYBRID_SCSC_LFSR_EN_TZASC_VIO (1 << 14) +#define VYBRID_SCSC_LFSR_LFSR1_SEED (1 << 13) +#define VYBRID_SCSC_LFSR_LFSR0_SEED (1 << 12) +#define VYBRID_SCSC_LFSR_ACTIVE_SEL_4_5 (1 << 11) +#define VYBRID_SCSC_LFSR_ACTIVE_SEL_2_3 (1 << 10) +#define VYBRID_SCSC_LFSR_TAMPER5_INV (1 << 9) +#define VYBRID_SCSC_LFSR_TAMPER4_INV (1 << 8) +#define VYBRID_SCSC_LFSR_TAMPER3_INV (1 << 7) +#define VYBRID_SCSC_LFSR_TAMPER2_INV (1 << 6) +#define VYBRID_SCSC_LFSR_TAMPER1_INV (1 << 5) +#define VYBRID_SCSC_LFSR_TAMPER0_INV (1 << 4) + +#endif /*__ARCH_ARM_MACH_VYBRID_SCSC_REGS_H__ */ diff --git a/board/freescale/vybrid/vybrid.c b/board/freescale/vybrid/vybrid.c index a1507e170b..c9b423888f 100644 --- a/board/freescale/vybrid/vybrid.c +++ b/board/freescale/vybrid/vybrid.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include #include @@ -512,9 +513,23 @@ int board_early_init_f(void) int board_init(void) { + u32 temp; + struct vybrid_scsc_reg *scsc = (struct vybrid_scsc_reg *)SCSCM_BASE_ADDR; + /* address of boot parameters */ gd->bd->bi_boot_params = CONFIG_SYS_SDRAM_BASE + 0x100; + /* + * Enable external 32K Oscillator + * + * The internal clock experiences significant drift + * so we must use the external oscillator in order + * to maintain correct time in the hwclock + */ + temp = __raw_readl(&scsc->sosc_ctr); + temp |= VYBRID_SCSC_SICR_CTR_SOSC_EN; + __raw_writel(temp, &scsc->sosc_ctr); + return 0; } -- cgit v1.2.3