iMX28: Initial support for iMX28 CPU
This patch supports:
- Timers
- Debug UART
- Clock
Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
diff --git a/arch/arm/cpu/arm926ejs/mx28/Makefile b/arch/arm/cpu/arm926ejs/mx28/Makefile
new file mode 100644
index 0000000..98504f9
--- /dev/null
+++ b/arch/arm/cpu/arm926ejs/mx28/Makefile
@@ -0,0 +1,46 @@
+#
+# (C) Copyright 2000-2006
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# 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
+#
+
+include $(TOPDIR)/config.mk
+
+LIB = $(obj)lib$(SOC).o
+
+COBJS = clock.o mx28.o timer.o
+
+SRCS := $(START:.o=.S) $(COBJS:.o=.c)
+OBJS := $(addprefix $(obj),$(COBJS))
+START := $(addprefix $(obj),$(START))
+
+all: $(obj).depend $(LIB)
+
+$(LIB): $(OBJS)
+ $(call cmd_link_o_target, $(OBJS))
+
+#########################################################################
+
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
+
+sinclude $(obj).depend
+
+#########################################################################
diff --git a/arch/arm/cpu/arm926ejs/mx28/clock.c b/arch/arm/cpu/arm926ejs/mx28/clock.c
new file mode 100644
index 0000000..f698506
--- /dev/null
+++ b/arch/arm/cpu/arm926ejs/mx28/clock.c
@@ -0,0 +1,355 @@
+/*
+ * Freescale i.MX28 clock setup code
+ *
+ * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
+ * on behalf of DENX Software Engineering GmbH
+ *
+ * Based on code from LTIB:
+ * Copyright (C) 2010 Freescale Semiconductor, Inc.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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
+ */
+
+#include <common.h>
+#include <asm/errno.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/imx-regs.h>
+
+/* The PLL frequency is always 480MHz, see section 10.2 in iMX28 datasheet. */
+#define PLL_FREQ_KHZ 480000
+#define PLL_FREQ_COEF 18
+/* The XTAL frequency is always 24MHz, see section 10.2 in iMX28 datasheet. */
+#define XTAL_FREQ_KHZ 24000
+
+#define PLL_FREQ_MHZ (PLL_FREQ_KHZ / 1000)
+#define XTAL_FREQ_MHZ (XTAL_FREQ_KHZ / 1000)
+
+static uint32_t mx28_get_pclk(void)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+ uint32_t clkctrl, clkseq, clkfrac;
+ uint32_t frac, div;
+
+ clkctrl = readl(&clkctrl_regs->hw_clkctrl_cpu);
+
+ /* No support of fractional divider calculation */
+ if (clkctrl &
+ (CLKCTRL_CPU_DIV_XTAL_FRAC_EN | CLKCTRL_CPU_DIV_CPU_FRAC_EN)) {
+ return 0;
+ }
+
+ clkseq = readl(&clkctrl_regs->hw_clkctrl_clkseq);
+
+ /* XTAL Path */
+ if (clkseq & CLKCTRL_CLKSEQ_BYPASS_CPU) {
+ div = (clkctrl & CLKCTRL_CPU_DIV_XTAL_MASK) >>
+ CLKCTRL_CPU_DIV_XTAL_OFFSET;
+ return XTAL_FREQ_MHZ / div;
+ }
+
+ /* REF Path */
+ clkfrac = readl(&clkctrl_regs->hw_clkctrl_frac0);
+ frac = clkfrac & CLKCTRL_FRAC0_CPUFRAC_MASK;
+ div = clkctrl & CLKCTRL_CPU_DIV_CPU_MASK;
+ return (PLL_FREQ_MHZ * PLL_FREQ_COEF / frac) / div;
+}
+
+static uint32_t mx28_get_hclk(void)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+ uint32_t div;
+ uint32_t clkctrl;
+
+ clkctrl = readl(&clkctrl_regs->hw_clkctrl_hbus);
+
+ /* No support of fractional divider calculation */
+ if (clkctrl & CLKCTRL_HBUS_DIV_FRAC_EN)
+ return 0;
+
+ div = clkctrl & CLKCTRL_HBUS_DIV_MASK;
+ return mx28_get_pclk() / div;
+}
+
+static uint32_t mx28_get_emiclk(void)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+ uint32_t frac, div;
+ uint32_t clkctrl, clkseq, clkfrac;
+
+ clkseq = readl(&clkctrl_regs->hw_clkctrl_clkseq);
+ clkctrl = readl(&clkctrl_regs->hw_clkctrl_emi);
+
+ /* XTAL Path */
+ if (clkseq & CLKCTRL_CLKSEQ_BYPASS_EMI) {
+ div = (clkctrl & CLKCTRL_EMI_DIV_XTAL_MASK) >>
+ CLKCTRL_EMI_DIV_XTAL_OFFSET;
+ return XTAL_FREQ_MHZ / div;
+ }
+
+ clkfrac = readl(&clkctrl_regs->hw_clkctrl_frac0);
+
+ /* REF Path */
+ frac = (clkfrac & CLKCTRL_FRAC0_EMIFRAC_MASK) >>
+ CLKCTRL_FRAC0_EMIFRAC_OFFSET;
+ div = clkctrl & CLKCTRL_EMI_DIV_EMI_MASK;
+ return (PLL_FREQ_MHZ * PLL_FREQ_COEF / frac) / div;
+}
+
+static uint32_t mx28_get_gpmiclk(void)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+ uint32_t frac, div;
+ uint32_t clkctrl, clkseq, clkfrac;
+
+ clkseq = readl(&clkctrl_regs->hw_clkctrl_clkseq);
+ clkctrl = readl(&clkctrl_regs->hw_clkctrl_gpmi);
+
+ /* XTAL Path */
+ if (clkseq & CLKCTRL_CLKSEQ_BYPASS_GPMI) {
+ div = clkctrl & CLKCTRL_GPMI_DIV_MASK;
+ return XTAL_FREQ_MHZ / div;
+ }
+
+ clkfrac = readl(&clkctrl_regs->hw_clkctrl_frac1);
+
+ /* REF Path */
+ frac = (clkfrac & CLKCTRL_FRAC1_GPMIFRAC_MASK) >>
+ CLKCTRL_FRAC1_GPMIFRAC_OFFSET;
+ div = clkctrl & CLKCTRL_GPMI_DIV_MASK;
+ return (PLL_FREQ_MHZ * PLL_FREQ_COEF / frac) / div;
+}
+
+/*
+ * Set IO clock frequency, in kHz
+ */
+void mx28_set_ioclk(enum mxs_ioclock io, uint32_t freq)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+ uint32_t div;
+
+ if (freq == 0)
+ return;
+
+ if (io > MXC_IOCLK1)
+ return;
+
+ div = (PLL_FREQ_KHZ * PLL_FREQ_COEF) / freq;
+
+ if (div < 18)
+ div = 18;
+
+ if (div > 35)
+ div = 35;
+
+ if (io == MXC_IOCLK0) {
+ writel(CLKCTRL_FRAC0_CLKGATEIO0,
+ &clkctrl_regs->hw_clkctrl_frac0_set);
+ clrsetbits_le32(&clkctrl_regs->hw_clkctrl_frac0,
+ CLKCTRL_FRAC0_IO0FRAC_MASK,
+ div << CLKCTRL_FRAC0_IO0FRAC_OFFSET);
+ writel(CLKCTRL_FRAC0_CLKGATEIO0,
+ &clkctrl_regs->hw_clkctrl_frac0_clr);
+ } else {
+ writel(CLKCTRL_FRAC0_CLKGATEIO1,
+ &clkctrl_regs->hw_clkctrl_frac0_set);
+ clrsetbits_le32(&clkctrl_regs->hw_clkctrl_frac0,
+ CLKCTRL_FRAC0_IO1FRAC_MASK,
+ div << CLKCTRL_FRAC0_IO1FRAC_OFFSET);
+ writel(CLKCTRL_FRAC0_CLKGATEIO1,
+ &clkctrl_regs->hw_clkctrl_frac0_clr);
+ }
+}
+
+/*
+ * Get IO clock, returns IO clock in kHz
+ */
+static uint32_t mx28_get_ioclk(enum mxs_ioclock io)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+ uint32_t tmp, ret;
+
+ if (io > MXC_IOCLK1)
+ return 0;
+
+ tmp = readl(&clkctrl_regs->hw_clkctrl_frac0);
+
+ if (io == MXC_IOCLK0)
+ ret = (tmp & CLKCTRL_FRAC0_IO0FRAC_MASK) >>
+ CLKCTRL_FRAC0_IO0FRAC_OFFSET;
+ else
+ ret = (tmp & CLKCTRL_FRAC0_IO1FRAC_MASK) >>
+ CLKCTRL_FRAC0_IO1FRAC_OFFSET;
+
+ return (PLL_FREQ_KHZ * PLL_FREQ_COEF) / ret;
+}
+
+/*
+ * Configure SSP clock frequency, in kHz
+ */
+void mx28_set_sspclk(enum mxs_sspclock ssp, uint32_t freq, int xtal)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+ uint32_t clk, clkreg;
+
+ if (ssp > MXC_SSPCLK3)
+ return;
+
+ clkreg = (uint32_t)(&clkctrl_regs->hw_clkctrl_ssp0) +
+ (ssp * sizeof(struct mx28_register));
+
+ clrbits_le32(clkreg, CLKCTRL_SSP_CLKGATE);
+ while (readl(clkreg) & CLKCTRL_SSP_CLKGATE)
+ ;
+
+ if (xtal)
+ clk = XTAL_FREQ_KHZ;
+ else
+ clk = mx28_get_ioclk(ssp >> 1);
+
+ if (freq > clk)
+ return;
+
+ /* Calculate the divider and cap it if necessary */
+ clk /= freq;
+ if (clk > CLKCTRL_SSP_DIV_MASK)
+ clk = CLKCTRL_SSP_DIV_MASK;
+
+ clrsetbits_le32(clkreg, CLKCTRL_SSP_DIV_MASK, clk);
+ while (readl(clkreg) & CLKCTRL_SSP_BUSY)
+ ;
+
+ if (xtal)
+ writel(CLKCTRL_CLKSEQ_BYPASS_SSP0 << ssp,
+ &clkctrl_regs->hw_clkctrl_clkseq_set);
+ else
+ writel(CLKCTRL_CLKSEQ_BYPASS_SSP0 << ssp,
+ &clkctrl_regs->hw_clkctrl_clkseq_clr);
+}
+
+/*
+ * Return SSP frequency, in kHz
+ */
+static uint32_t mx28_get_sspclk(enum mxs_sspclock ssp)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+ uint32_t clkreg;
+ uint32_t clk, tmp;
+
+ if (ssp > MXC_SSPCLK3)
+ return 0;
+
+ tmp = readl(&clkctrl_regs->hw_clkctrl_clkseq);
+ if (tmp & (CLKCTRL_CLKSEQ_BYPASS_SSP0 << ssp))
+ return XTAL_FREQ_KHZ;
+
+ clkreg = (uint32_t)(&clkctrl_regs->hw_clkctrl_ssp0) +
+ (ssp * sizeof(struct mx28_register));
+
+ tmp = readl(clkreg) & CLKCTRL_SSP_DIV_MASK;
+
+ if (tmp == 0)
+ return 0;
+
+ clk = mx28_get_ioclk(ssp >> 1);
+
+ return clk / tmp;
+}
+
+/*
+ * Set SSP/MMC bus frequency, in kHz)
+ */
+void mx28_set_ssp_busclock(unsigned int bus, uint32_t freq)
+{
+ struct mx28_ssp_regs *ssp_regs;
+ const uint32_t sspclk = mx28_get_sspclk(bus);
+ uint32_t reg;
+ uint32_t divide, rate, tgtclk;
+
+ ssp_regs = (struct mx28_ssp_regs *)(MXS_SSP0_BASE + (bus * 0x2000));
+
+ /*
+ * SSP bit rate = SSPCLK / (CLOCK_DIVIDE * (1 + CLOCK_RATE)),
+ * CLOCK_DIVIDE has to be an even value from 2 to 254, and
+ * CLOCK_RATE could be any integer from 0 to 255.
+ */
+ for (divide = 2; divide < 254; divide += 2) {
+ rate = sspclk / freq / divide;
+ if (rate <= 256)
+ break;
+ }
+
+ tgtclk = sspclk / divide / rate;
+ while (tgtclk > freq) {
+ rate++;
+ tgtclk = sspclk / divide / rate;
+ }
+ if (rate > 256)
+ rate = 256;
+
+ /* Always set timeout the maximum */
+ reg = SSP_TIMING_TIMEOUT_MASK |
+ (divide << SSP_TIMING_CLOCK_DIVIDE_OFFSET) |
+ ((rate - 1) << SSP_TIMING_CLOCK_RATE_OFFSET);
+ writel(reg, &ssp_regs->hw_ssp_timing);
+
+ debug("SPI%d: Set freq rate to %d KHz (requested %d KHz)\n",
+ bus, tgtclk, freq);
+}
+
+uint32_t mxc_get_clock(enum mxc_clock clk)
+{
+ switch (clk) {
+ case MXC_ARM_CLK:
+ return mx28_get_pclk() * 1000000;
+ case MXC_GPMI_CLK:
+ return mx28_get_gpmiclk() * 1000000;
+ case MXC_AHB_CLK:
+ case MXC_IPG_CLK:
+ return mx28_get_hclk() * 1000000;
+ case MXC_EMI_CLK:
+ return mx28_get_emiclk();
+ case MXC_IO0_CLK:
+ return mx28_get_ioclk(MXC_IOCLK0);
+ case MXC_IO1_CLK:
+ return mx28_get_ioclk(MXC_IOCLK1);
+ case MXC_SSP0_CLK:
+ return mx28_get_sspclk(MXC_SSPCLK0);
+ case MXC_SSP1_CLK:
+ return mx28_get_sspclk(MXC_SSPCLK1);
+ case MXC_SSP2_CLK:
+ return mx28_get_sspclk(MXC_SSPCLK2);
+ case MXC_SSP3_CLK:
+ return mx28_get_sspclk(MXC_SSPCLK3);
+ }
+
+ return 0;
+}
diff --git a/arch/arm/cpu/arm926ejs/mx28/mx28.c b/arch/arm/cpu/arm926ejs/mx28/mx28.c
new file mode 100644
index 0000000..446ea8b
--- /dev/null
+++ b/arch/arm/cpu/arm926ejs/mx28/mx28.c
@@ -0,0 +1,193 @@
+/*
+ * Freescale i.MX28 common code
+ *
+ * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
+ * on behalf of DENX Software Engineering GmbH
+ *
+ * Based on code from LTIB:
+ * Copyright (C) 2010 Freescale Semiconductor, Inc.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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
+ */
+
+#include <common.h>
+#include <asm/errno.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/gpio.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/arch/sys_proto.h>
+
+/* 1 second delay should be plenty of time for block reset. */
+#define RESET_MAX_TIMEOUT 1000000
+
+#define MX28_BLOCK_SFTRST (1 << 31)
+#define MX28_BLOCK_CLKGATE (1 << 30)
+
+/* Lowlevel init isn't used on i.MX28, so just have a dummy here */
+inline void lowlevel_init(void) {}
+
+void reset_cpu(ulong ignored) __attribute__((noreturn));
+
+void reset_cpu(ulong ignored)
+{
+
+ struct mx28_rtc_regs *rtc_regs =
+ (struct mx28_rtc_regs *)MXS_RTC_BASE;
+
+ /* Wait 1 uS before doing the actual watchdog reset */
+ writel(1, &rtc_regs->hw_rtc_watchdog);
+ writel(RTC_CTRL_WATCHDOGEN, &rtc_regs->hw_rtc_ctrl_set);
+
+ /* Endless loop, reset will exit from here */
+ for (;;)
+ ;
+}
+
+int mx28_wait_mask_set(struct mx28_register *reg, uint32_t mask, int timeout)
+{
+ while (--timeout) {
+ if ((readl(®->reg) & mask) == mask)
+ break;
+ udelay(1);
+ }
+
+ return !timeout;
+}
+
+int mx28_wait_mask_clr(struct mx28_register *reg, uint32_t mask, int timeout)
+{
+ while (--timeout) {
+ if ((readl(®->reg) & mask) == 0)
+ break;
+ udelay(1);
+ }
+
+ return !timeout;
+}
+
+int mx28_reset_block(struct mx28_register *reg)
+{
+ /* Clear SFTRST */
+ writel(MX28_BLOCK_SFTRST, ®->reg_clr);
+
+ if (mx28_wait_mask_clr(reg, MX28_BLOCK_SFTRST, RESET_MAX_TIMEOUT))
+ return 1;
+
+ /* Clear CLKGATE */
+ writel(MX28_BLOCK_CLKGATE, ®->reg_clr);
+
+ /* Set SFTRST */
+ writel(MX28_BLOCK_SFTRST, ®->reg_set);
+
+ /* Wait for CLKGATE being set */
+ if (mx28_wait_mask_set(reg, MX28_BLOCK_CLKGATE, RESET_MAX_TIMEOUT))
+ return 1;
+
+ /* Clear SFTRST */
+ writel(MX28_BLOCK_SFTRST, ®->reg_clr);
+
+ if (mx28_wait_mask_clr(reg, MX28_BLOCK_SFTRST, RESET_MAX_TIMEOUT))
+ return 1;
+
+ /* Clear CLKGATE */
+ writel(MX28_BLOCK_CLKGATE, ®->reg_clr);
+
+ if (mx28_wait_mask_clr(reg, MX28_BLOCK_CLKGATE, RESET_MAX_TIMEOUT))
+ return 1;
+
+ return 0;
+}
+
+#ifdef CONFIG_ARCH_CPU_INIT
+int arch_cpu_init(void)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+ /*
+ * Enable NAND clock
+ */
+ /* Clear bypass bit */
+ writel(CLKCTRL_CLKSEQ_BYPASS_GPMI,
+ &clkctrl_regs->hw_clkctrl_clkseq_set);
+
+ /* Set GPMI clock to ref_gpmi / 12 */
+ clrsetbits_le32(&clkctrl_regs->hw_clkctrl_gpmi,
+ CLKCTRL_GPMI_CLKGATE | CLKCTRL_GPMI_DIV_MASK, 1);
+
+ udelay(1000);
+
+ return 0;
+}
+#endif
+
+#if defined(CONFIG_DISPLAY_CPUINFO)
+int print_cpuinfo(void)
+{
+ printf("Freescale i.MX28 family\n");
+ return 0;
+}
+#endif
+
+int do_mx28_showclocks(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
+{
+ printf("CPU: %3d MHz\n", mxc_get_clock(MXC_ARM_CLK) / 1000000);
+ printf("BUS: %3d MHz\n", mxc_get_clock(MXC_AHB_CLK) / 1000000);
+ printf("EMI: %3d MHz\n", mxc_get_clock(MXC_EMI_CLK));
+ printf("GPMI: %3d MHz\n", mxc_get_clock(MXC_GPMI_CLK) / 1000000);
+ return 0;
+}
+
+/*
+ * Initializes on-chip ethernet controllers.
+ */
+#ifdef CONFIG_CMD_NET
+int cpu_eth_init(bd_t *bis)
+{
+ struct mx28_clkctrl_regs *clkctrl_regs =
+ (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+ /* Turn on ENET clocks */
+ clrbits_le32(&clkctrl_regs->hw_clkctrl_enet,
+ CLKCTRL_ENET_SLEEP | CLKCTRL_ENET_DISABLE);
+
+ /* Set up ENET PLL for 50 MHz */
+ /* Power on ENET PLL */
+ writel(CLKCTRL_PLL2CTRL0_POWER,
+ &clkctrl_regs->hw_clkctrl_pll2ctrl0_set);
+
+ udelay(10);
+
+ /* Gate on ENET PLL */
+ writel(CLKCTRL_PLL2CTRL0_CLKGATE,
+ &clkctrl_regs->hw_clkctrl_pll2ctrl0_clr);
+
+ /* Enable pad output */
+ setbits_le32(&clkctrl_regs->hw_clkctrl_enet, CLKCTRL_ENET_CLK_OUT_EN);
+
+ return 0;
+}
+#endif
+
+U_BOOT_CMD(
+ clocks, CONFIG_SYS_MAXARGS, 1, do_mx28_showclocks,
+ "display clocks",
+ ""
+);
diff --git a/arch/arm/cpu/arm926ejs/mx28/timer.c b/arch/arm/cpu/arm926ejs/mx28/timer.c
new file mode 100644
index 0000000..dbc904d
--- /dev/null
+++ b/arch/arm/cpu/arm926ejs/mx28/timer.c
@@ -0,0 +1,141 @@
+/*
+ * Freescale i.MX28 timer driver
+ *
+ * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
+ * on behalf of DENX Software Engineering GmbH
+ *
+ * Based on code from LTIB:
+ * (C) Copyright 2009-2010 Freescale Semiconductor, Inc.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/arch/sys_proto.h>
+
+/* Maximum fixed count */
+#define TIMER_LOAD_VAL 0xffffffff
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define timestamp (gd->tbl)
+#define lastdec (gd->lastinc)
+
+/*
+ * This driver uses 1kHz clock source.
+ */
+#define MX28_INCREMENTER_HZ 1000
+
+static inline unsigned long tick_to_time(unsigned long tick)
+{
+ return tick / (MX28_INCREMENTER_HZ / CONFIG_SYS_HZ);
+}
+
+static inline unsigned long time_to_tick(unsigned long time)
+{
+ return time * (MX28_INCREMENTER_HZ / CONFIG_SYS_HZ);
+}
+
+/* Calculate how many ticks happen in "us" microseconds */
+static inline unsigned long us_to_tick(unsigned long us)
+{
+ return (us * MX28_INCREMENTER_HZ) / 1000000;
+}
+
+int timer_init(void)
+{
+ struct mx28_timrot_regs *timrot_regs =
+ (struct mx28_timrot_regs *)MXS_TIMROT_BASE;
+
+ /* Reset Timers and Rotary Encoder module */
+ mx28_reset_block(&timrot_regs->hw_timrot_rotctrl_reg);
+
+ /* Set fixed_count to 0 */
+ writel(0, &timrot_regs->hw_timrot_fixed_count0);
+
+ /* Set UPDATE bit and 1Khz frequency */
+ writel(TIMROT_TIMCTRLn_UPDATE | TIMROT_TIMCTRLn_RELOAD |
+ TIMROT_TIMCTRLn_SELECT_1KHZ_XTAL,
+ &timrot_regs->hw_timrot_timctrl0);
+
+ /* Set fixed_count to maximal value */
+ writel(TIMER_LOAD_VAL, &timrot_regs->hw_timrot_fixed_count0);
+
+ return 0;
+}
+
+ulong get_timer(ulong base)
+{
+ struct mx28_timrot_regs *timrot_regs =
+ (struct mx28_timrot_regs *)MXS_TIMROT_BASE;
+
+ /* Current tick value */
+ uint32_t now = readl(&timrot_regs->hw_timrot_running_count0);
+
+ if (lastdec >= now) {
+ /*
+ * normal mode (non roll)
+ * move stamp forward with absolut diff ticks
+ */
+ timestamp += (lastdec - now);
+ } else {
+ /* we have rollover of decrementer */
+ timestamp += (TIMER_LOAD_VAL - now) + lastdec;
+
+ }
+ lastdec = now;
+
+ return tick_to_time(timestamp) - base;
+}
+
+/* We use the HW_DIGCTL_MICROSECONDS register for sub-millisecond timer. */
+#define MX28_HW_DIGCTL_MICROSECONDS 0x8001c0c0
+
+void __udelay(unsigned long usec)
+{
+ uint32_t old, new, incr;
+ uint32_t counter = 0;
+
+ old = readl(MX28_HW_DIGCTL_MICROSECONDS);
+
+ while (counter < usec) {
+ new = readl(MX28_HW_DIGCTL_MICROSECONDS);
+
+ /* Check if the timer wrapped. */
+ if (new < old) {
+ incr = 0xffffffff - old;
+ incr += new;
+ } else {
+ incr = new - old;
+ }
+
+ /*
+ * Check if we are close to the maximum time and the counter
+ * would wrap if incremented. If that's the case, break out
+ * from the loop as the requested delay time passed.
+ */
+ if (counter + incr < counter)
+ break;
+
+ counter += incr;
+ old = new;
+ }
+}