mediatek: Share PLL code among similar SOCs

Refactor PLL code which will be reused among similar SOCs.

BUG=b:80501386
BRANCH=none
TEST=Boots correctly on Elm

Change-Id: I11f044fbef93d4f5f4388368c510958d2b0ae66c
Signed-off-by: Tristan Shieh <tristan.shieh@mediatek.com>
Reviewed-on: https://review.coreboot.org/27305
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 161 insertions, 0 deletions

diff --git a/src/soc/mediatek/common/include/soc/pll_common.h b/src/soc/mediatek/common/include/soc/pll_common.h
new file mode 100644
index 0000000000..480371b67c
--- /dev/null
+++ b/src/soc/mediatek/common/include/soc/pll_common.h
@@ -0,0 +1,73 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 MediaTek Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ */
+
+#ifndef SOC_MEDIATEK_PLL_COMMON_H
+#define SOC_MEDIATEK_PLL_COMMON_H
+
+#include <soc/addressmap.h>
+#include <types.h>
+
+/* These need to be macros for use in static initializers. */
+#define mtk_topckgen ((struct mtk_topckgen_regs *)CKSYS_BASE)
+#define mtk_apmixed  ((struct mtk_apmixed_regs *)APMIXED_BASE)
+
+#define PLL_PWR_ON		(1 << 0)
+#define PLL_EN			(1 << 0)
+#define PLL_ISO			(1 << 1)
+#define PLL_RSTB_SHIFT		(24)
+#define NO_RSTB_SHIFT		(255)
+#define PLL_PCW_CHG		(1 << 31)
+#define PLL_POSTDIV_MASK	0x7
+
+struct mux {
+	void *reg;
+	void *upd_reg;
+	u8 mux_shift;
+	u8 mux_width;
+	u8 upd_shift;
+};
+
+struct pll {
+	void *reg;
+	void *pwr_reg;
+	void *div_reg;
+	void *pcw_reg;
+	const u32 *div_rate;
+	u8 rstb_shift;
+	u8 pcwbits;
+	u8 div_shift;
+	u8 pcw_shift;
+};
+
+#define PLL(_id, _reg, _pwr_reg, _rstb, _pcwbits, _div_reg, _div_shift,	\
+			_pcw_reg, _pcw_shift, _div_rate)		\
+	[_id] = {							\
+		.reg = &mtk_apmixed->_reg,				\
+		.pwr_reg = &mtk_apmixed->_pwr_reg,			\
+		.rstb_shift = _rstb,					\
+		.pcwbits = _pcwbits,					\
+		.div_reg = &mtk_apmixed->_div_reg,			\
+		.div_shift = _div_shift,				\
+		.pcw_reg = &mtk_apmixed->_pcw_reg,			\
+		.pcw_shift = _pcw_shift,				\
+		.div_rate = _div_rate,					\
+	}
+
+void pll_set_pcw_change(const struct pll *pll);
+void mux_set_sel(const struct mux *mux, u32 sel);
+int pll_set_rate(const struct pll *pll, u32 rate);
+void mt_pll_init(void);
+
+#endif
diff --git a/src/soc/mediatek/common/pll.c b/src/soc/mediatek/common/pll.c
new file mode 100644
index 0000000000..e087be38a2
--- /dev/null
+++ b/src/soc/mediatek/common/pll.c
@@ -0,0 +1,88 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 MediaTek Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ */
+
+#include <arch/io.h>
+#include <assert.h>
+#include <soc/pll.h>
+
+#define GENMASK(h, l) (BIT(h + 1) - BIT(l))
+
+void mux_set_sel(const struct mux *mux, u32 sel)
+{
+	u32 mask = GENMASK(mux->mux_width - 1, 0);
+	u32 val = read32(mux->reg);
+
+	val &= ~(mask << mux->mux_shift);
+	val |= (sel & mask) << mux->mux_shift;
+	write32(mux->reg, val);
+	if (mux->upd_reg)
+		write32(mux->upd_reg, 1 << mux->upd_shift);
+}
+
+static void pll_calc_values(const struct pll *pll, u32 *pcw, u32 *postdiv,
+			    u32 freq)
+{
+	const u32 fin_hz = CLK26M_HZ;
+	const u32 *div_rate = pll->div_rate;
+	u32 val;
+
+	assert(freq <= div_rate[0]);
+	assert(freq >= 1 * GHz / 16);
+
+	for (val = 1; div_rate[val] != 0; val++) {
+		if (freq > div_rate[val])
+			break;
+	}
+	val--;
+	*postdiv = val;
+
+	/* _pcw = freq * 2^postdiv / fin * 2^pcwbits_fractional */
+	val += pll->pcwbits - PCW_INTEGER_BITS;
+
+	*pcw = ((u64)freq << val) / fin_hz;
+}
+
+static void pll_set_rate_regs(const struct pll *pll, u32 pcw, u32 postdiv)
+{
+	u32 val;
+
+	/* set postdiv */
+	val = read32(pll->div_reg);
+	val &= ~(PLL_POSTDIV_MASK << pll->div_shift);
+	val |= postdiv << pll->div_shift;
+
+	/* set postdiv and pcw at the same time if on the same register */
+	if (pll->div_reg != pll->pcw_reg) {
+		write32(pll->div_reg, val);
+		val = read32(pll->pcw_reg);
+	}
+
+	/* set pcw */
+	val &= ~GENMASK(pll->pcw_shift + pll->pcwbits - 1, pll->pcw_shift);
+	val |= pcw << pll->pcw_shift;
+	write32(pll->pcw_reg, val);
+
+	pll_set_pcw_change(pll);
+}
+
+int pll_set_rate(const struct pll *pll, u32 rate)
+{
+	u32 pcw, postdiv;
+
+	pll_calc_values(pll, &pcw, &postdiv, rate);
+	pll_set_rate_regs(pll, pcw, postdiv);
+
+	return 0;
+}