WIP: Initial support for Samsung Exynos 5250 ARM CPU

Samsung SoC files, including Exynos5 (a Cortex-A15
implementation). Since this is an SoC we'll forego the x86-style
{north,south}bridge and cpu distinction. We may try to split some
stuff out before the final version if prudent.

Change-Id: Ie068e9dc3dd836c83d90e282b10d5202e7a4ba9b
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: http://review.coreboot.org/2005
Tested-by: build bot (Jenkins)

1 files changed, 205 insertions, 0 deletions

diff --git a/src/cpu/samsung/s5p-common/pwm.c b/src/cpu/samsung/s5p-common/pwm.c
new file mode 100644
index 0000000000..53004204c6
--- /dev/null
+++ b/src/cpu/samsung/s5p-common/pwm.c
@@ -0,0 +1,205 @@
+/*
+ * Copyright (C) 2011 Samsung Electronics
+ *
+ * Donghwa Lee <dh09.lee@samsung.com>
+ *
+ * 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 <pwm.h>
+#include <arch/io.h>
+//#include <arch/pwm.h>
+//#include <arch/clk.h>
+/* FIXME(dhendrix): this is a godawful mess of similar-but-different includes... */
+#include <cpu/samsung/exynos5-common/clk.h>
+#include <cpu/samsung/exynos5250/cpu.h>
+#include <cpu/samsung/exynos5250/periph.h>
+#include <cpu/samsung/s5p-common/pwm.h>
+#include <cpu/samsung/s5p-common/clk.h>
+//#include <arch/periph.h>
+
+int pwm_enable(int pwm_id)
+{
+	const struct s5p_timer *pwm =
+			(struct s5p_timer *)samsung_get_base_timer();
+	unsigned long tcon;
+
+	tcon = readl(&pwm->tcon);
+	tcon |= TCON_START(pwm_id);
+
+	writel(tcon, &pwm->tcon);
+
+	return 0;
+}
+
+int pwm_check_enabled(int pwm_id)
+{
+	const struct s5p_timer *pwm =
+			(struct s5p_timer *)samsung_get_base_timer();
+	const unsigned long tcon = readl(&pwm->tcon);
+
+	return tcon & TCON_START(pwm_id);
+}
+
+void pwm_disable(int pwm_id)
+{
+	const struct s5p_timer *pwm =
+			(struct s5p_timer *)samsung_get_base_timer();
+	unsigned long tcon;
+
+	tcon = readl(&pwm->tcon);
+	tcon &= ~TCON_START(pwm_id);
+
+	writel(tcon, &pwm->tcon);
+}
+
+static unsigned long pwm_calc_tin(int pwm_id, unsigned long freq)
+{
+	unsigned long tin_parent_rate;
+	unsigned int div;
+
+	tin_parent_rate = clock_get_periph_rate(PERIPH_ID_PWM0);
+
+	for (div = 2; div <= 16; div *= 2) {
+		if ((tin_parent_rate / (div << 16)) < freq)
+			return tin_parent_rate / div;
+	}
+
+	return tin_parent_rate / 16;
+}
+
+#define NS_IN_SEC 1000000000UL
+
+int pwm_config(int pwm_id, int duty_ns, int period_ns)
+{
+	const struct s5p_timer *pwm =
+			(struct s5p_timer *)samsung_get_base_timer();
+	unsigned int offset;
+	unsigned long tin_rate;
+	unsigned long tin_ns;
+	unsigned long frequency;
+	unsigned long tcon;
+	unsigned long tcnt;
+	unsigned long tcmp;
+
+	/*
+	 * We currently avoid using 64bit arithmetic by using the
+	 * fact that anything faster than 1GHz is easily representable
+	 * by 32bits.
+	 */
+	if (period_ns > NS_IN_SEC || duty_ns > NS_IN_SEC || period_ns == 0)
+		return -1;
+//		return -ERANGE;
+
+	if (duty_ns > period_ns)
+		return -1;
+//		return -EINVAL;
+
+	frequency = NS_IN_SEC / period_ns;
+
+	/* Check to see if we are changing the clock rate of the PWM */
+	tin_rate = pwm_calc_tin(pwm_id, frequency);
+
+	tin_ns = NS_IN_SEC / tin_rate;
+	tcnt = period_ns / tin_ns;
+
+	/* Note, counters count down */
+	tcmp = duty_ns / tin_ns;
+	tcmp = tcnt - tcmp;
+
+	/* Update the PWM register block. */
+	offset = pwm_id * 3;
+	if (pwm_id < 4) {
+		writel(tcnt, &pwm->tcntb0 + offset);
+		writel(tcmp, &pwm->tcmpb0 + offset);
+	}
+
+	tcon = readl(&pwm->tcon);
+	tcon |= TCON_UPDATE(pwm_id);
+	if (pwm_id < 4)
+		tcon |= TCON_AUTO_RELOAD(pwm_id);
+	else
+		tcon |= TCON4_AUTO_RELOAD;
+	writel(tcon, &pwm->tcon);
+
+	tcon &= ~TCON_UPDATE(pwm_id);
+	writel(tcon, &pwm->tcon);
+
+	return 0;
+}
+
+int pwm_init(int pwm_id, int div, int invert)
+{
+	u32 val;
+	const struct s5p_timer *pwm =
+			(struct s5p_timer *)samsung_get_base_timer();
+	unsigned long ticks_per_period;
+	unsigned int offset, prescaler;
+
+	/*
+	 * Timer Freq(HZ) =
+	 *	PWM_CLK / { (prescaler_value + 1) * (divider_value) }
+	 */
+
+	val = readl(&pwm->tcfg0);
+	if (pwm_id < 2) {
+		prescaler = PRESCALER_0;
+		val &= ~0xff;
+		val |= (prescaler & 0xff);
+	} else {
+		prescaler = PRESCALER_1;
+		val &= ~(0xff << 8);
+		val |= (prescaler & 0xff) << 8;
+	}
+	writel(val, &pwm->tcfg0);
+	val = readl(&pwm->tcfg1);
+	val &= ~(0xf << MUX_DIV_SHIFT(pwm_id));
+	val |= (div & 0xf) << MUX_DIV_SHIFT(pwm_id);
+	writel(val, &pwm->tcfg1);
+
+
+	if (pwm_id == 4) {
+		/*
+		 * TODO(sjg): Use this as a countdown timer for now. We count
+		 * down from the maximum value to 0, then reset.
+		 */
+		ticks_per_period = -1UL;
+	} else {
+		const unsigned long pwm_hz = 1000;
+		unsigned long timer_rate_hz = clock_get_periph_rate(
+			PERIPH_ID_PWM0) / ((prescaler + 1) * (1 << div));
+
+		ticks_per_period = timer_rate_hz / pwm_hz;
+	}
+
+	/* set count value */
+	offset = pwm_id * 3;
+
+	writel(ticks_per_period, &pwm->tcntb0 + offset);
+
+	val = readl(&pwm->tcon) & ~(0xf << TCON_OFFSET(pwm_id));
+	if (invert && (pwm_id < 4))
+		val |= TCON_INVERTER(pwm_id);
+	writel(val, &pwm->tcon);
+
+	pwm_enable(pwm_id);
+
+	return 0;
+}