1 files changed, 110 insertions, 0 deletions
diff --git a/cpu/arm920t/ep93xx/speed.c b/cpu/arm920t/ep93xx/speed.c
new file mode 100644
index 0000000..c83a3bb
--- /dev/null
+++ b/cpu/arm920t/ep93xx/speed.c
@@ -0,0 +1,110 @@
+/*
+ * Cirrus Logic EP93xx PLL support.
+ *
+ * Copyright (C) 2009 Matthias Kaehlcke <matthias@kaehlcke.net>
+ *
+ * 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.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <common.h>
+#include <asm/arch/ep93xx.h>
+#include <asm/io.h>
+#include <div64.h>
+
+/*
+ * CONFIG_SYS_CLK_FREQ should be defined as the input frequency of the PLL.
+ *
+ * get_FCLK(), get_HCLK(), get_PCLK() and get_UCLK() return the clock of
+ * the specified bus in HZ.
+ */
+
+/*
+ * return the PLL output frequency
+ *
+ * PLL rate = CONFIG_SYS_CLK_FREQ * (X1FBD + 1) * (X2FBD + 1)
+ * / (X2IPD + 1) / 2^PS
+ */
+static ulong get_PLLCLK(uint32_t *pllreg)
+{
+	uint8_t i;
+	const uint32_t clkset = readl(pllreg);
+	uint64_t rate = CONFIG_SYS_CLK_FREQ;
+	rate *= ((clkset >> SYSCON_CLKSET_PLL_X1FBD1_SHIFT) & 0x1f) + 1;
+	rate *= ((clkset >> SYSCON_CLKSET_PLL_X2FBD2_SHIFT) & 0x3f) + 1;
+	do_div(rate, (clkset  & 0x1f) + 1);			/* X2IPD */
+	for (i = 0; i < ((clkset >> SYSCON_CLKSET_PLL_PS_SHIFT) & 3); i++)
+		rate >>= 1;
+
+	return (ulong)rate;
+}
+
+/* return FCLK frequency */
+ulong get_FCLK()
+{
+	const uint8_t fclk_divisors[] = { 1, 2, 4, 8, 16, 1, 1, 1 };
+	struct syscon_regs *syscon = (struct syscon_regs *)SYSCON_BASE;
+
+	const uint32_t clkset1 = readl(&syscon->clkset1);
+	const uint8_t fclk_div =
+		fclk_divisors[(clkset1 >> SYSCON_CLKSET1_FCLK_DIV_SHIFT) & 7];
+	const ulong fclk_rate = get_PLLCLK(&syscon->clkset1) / fclk_div;
+
+	return fclk_rate;
+}
+
+/* return HCLK frequency */
+ulong get_HCLK(void)
+{
+	const uint8_t hclk_divisors[] = { 1, 2, 4, 5, 6, 8, 16, 32 };
+	struct syscon_regs *syscon = (struct syscon_regs *)SYSCON_BASE;
+
+	const uint32_t clkset1 = readl(&syscon->clkset1);
+	const uint8_t hclk_div =
+		hclk_divisors[(clkset1 >> SYSCON_CLKSET1_HCLK_DIV_SHIFT) & 7];
+	const ulong hclk_rate = get_PLLCLK(&syscon->clkset1) / hclk_div;
+
+	return hclk_rate;
+}
+
+/* return PCLK frequency */
+ulong get_PCLK(void)
+{
+	const uint8_t pclk_divisors[] = { 1, 2, 4, 8 };
+	struct syscon_regs *syscon = (struct syscon_regs *)SYSCON_BASE;
+
+	const uint32_t clkset1 = readl(&syscon->clkset1);
+	const uint8_t pclk_div =
+		pclk_divisors[(clkset1 >> SYSCON_CLKSET1_PCLK_DIV_SHIFT) & 3];
+	const ulong pclk_rate = get_HCLK() / pclk_div;
+
+	return pclk_rate;
+}
+
+/* return UCLK frequency */
+ulong get_UCLK(void)
+{
+	struct syscon_regs *syscon = (struct syscon_regs *)SYSCON_BASE;
+	ulong uclk_rate;
+
+	const uint32_t value = readl(&syscon->pwrcnt);
+	if (value & SYSCON_PWRCNT_UART_BAUD)
+		uclk_rate = CONFIG_SYS_CLK_FREQ;
+	else
+		uclk_rate = CONFIG_SYS_CLK_FREQ / 2;
+
+	return uclk_rate;
+}