soc/mediatek/mt8192: Add function to raise the CCI frequency

Implement mt_pll_raise_cci_freq() in MT8192 to raise the CCI frequency.
Usage: mt_pll_raise_cci_freq(1400UL * MHz);

Signed-off-by: Weiyi Lu <weiyi.lu@mediatek.com>
Change-Id: I084cd7888b1dcfdeaef308b8bb3677d034497a30
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46411
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>

src/soc/mediatek/common/include/soc/pll_common.h

@@ -69,6 +69,7 @@ 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);
 void mt_pll_raise_little_cpu_freq(u32 freq);
+void mt_pll_raise_cci_freq(u32 freq);
 
 enum fmeter_type {
 	FMETER_ABIST = 0,

src/soc/mediatek/mt8192/pll.c

@@ -559,3 +559,28 @@ u32 mt_fmeter_get_freq_khz(enum fmeter_type type, u32 id)
 
 	return 0;
 }
+
+void mt_pll_raise_cci_freq(u32 freq)
+{
+	/* enable [4] intermediate clock armpll_divider_pll1_ck */
+	setbits32(&mtk_topckgen->clk_misc_cfg_0, 1 << 4);
+
+	/* switch cci clock source to intermediate clock */
+	clrsetbits32(&mt8192_mcucfg->bus_plldiv_cfg, MCU_MUX_MASK, MCU_MUX_SRC_DIV_PLL1);
+
+	/* disable ccipll frequency output */
+	clrbits32(plls[APMIXED_CCIPLL].reg, PLL_EN);
+
+	/* raise ccipll frequency */
+	pll_set_rate(&plls[APMIXED_CCIPLL], freq);
+
+	/* enable ccipll frequency output */
+	setbits32(plls[APMIXED_CCIPLL].reg, PLL_EN);
+	udelay(PLL_EN_DELAY);
+
+	/* switch cci clock source back to ccipll */
+	clrsetbits32(&mt8192_mcucfg->bus_plldiv_cfg, MCU_MUX_MASK, MCU_MUX_SRC_PLL);
+
+	/* disable [4] intermediate clock armpll_divider_pll1_ck */
+	clrbits32(&mtk_topckgen->clk_misc_cfg_0, 1 << 4);
+}