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authorJustin Waters <justin.waters@timesys.com>2012-12-19 11:13:24 -0500
committerJustin Waters <justin.waters@timesys.com>2012-12-19 11:23:03 -0500
commitda57bddb827ff0da2eb8da33b7081ff56d9dea2d (patch)
treee226c4cbfee6a440c401f0c647b17144a1727cac
parentd958fc844f245394d6926930ad9f24a01ba51e3c (diff)
vybrid: Fix hardware clock drift2011.12-mvf-201212191113
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 <B04178@freescale.com> Signed-off-by: Jiri Kotzian <B36968@freescale.com> Signed-off-by: Justin Waters <justin.waters@timesys.com>
-rw-r--r--arch/arm/include/asm/arch-vybrid/scsc_regs.h55
-rw-r--r--board/freescale/vybrid/vybrid.c15
2 files changed, 70 insertions, 0 deletions
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 00000000000..db019835a03
--- /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 a1507e170bc..c9b423888f0 100644
--- a/board/freescale/vybrid/vybrid.c
+++ b/board/freescale/vybrid/vybrid.c
@@ -30,6 +30,7 @@
#include <asm/errno.h>
#include <asm/arch/sys_proto.h>
#include <asm/arch/crm_regs.h>
+#include <asm/arch/scsc_regs.h>
#include <i2c.h>
#include <mmc.h>
#include <fsl_esdhc.h>
@@ -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;
}