ARM: tegra: don't exceed AVP limits when configuring PLLP

Based on the Tegra TRM, the system clock (which is the AVP clock) can
run up to 275MHz. On power on, the default sytem clock source is set to
PLLP_OUT0. In function clock_early_init(), PLLP_OUT0 will be set to
408MHz which is beyond system clock's upper limit.

The fix is to set the system clock to CLK_M before initializing PLLP,
and then switch back to PLLP_OUT4, which has an appropriate divider
configured, after PLLP has been configured

Implement this logic in new function tegra30_set_up_pllp(),
which sets up PLLP and all PLLP_OUT* dividers, and handles the AVP
clock switching. Remove the duplicate PLLP setup from pllx_set_rate()
and adjust_pllp_out_freqs().

Signed-off-by: Jimmy Zhang <jimmzhang@nvidia.com>
[swarren, significantly refactored the change]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>

1 files changed, 93 insertions, 1 deletions

diff --git a/arch/arm/cpu/tegra-common/clock.c b/arch/arm/cpu/tegra-common/clock.c
index 33bb19084b8..11c7435505c 100644
--- a/arch/arm/cpu/tegra-common/clock.c
+++ b/arch/arm/cpu/tegra-common/clock.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010-2013, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2010-2014, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -575,3 +575,95 @@ void clock_init(void)
 	/* Do any special system timer/TSC setup */
 	arch_timer_init();
 }
+
+static void set_avp_clock_source(u32 src)
+{
+	struct clk_rst_ctlr *clkrst =
+			(struct clk_rst_ctlr *)NV_PA_CLK_RST_BASE;
+	u32 val;
+
+	val = (src << SCLK_SWAKEUP_FIQ_SOURCE_SHIFT) |
+		(src << SCLK_SWAKEUP_IRQ_SOURCE_SHIFT) |
+		(src << SCLK_SWAKEUP_RUN_SOURCE_SHIFT) |
+		(src << SCLK_SWAKEUP_IDLE_SOURCE_SHIFT) |
+		(SCLK_SYS_STATE_RUN << SCLK_SYS_STATE_SHIFT);
+	writel(val, &clkrst->crc_sclk_brst_pol);
+	udelay(3);
+}
+
+/*
+ * This function is useful on Tegra30, and any later SoCs that have compatible
+ * PLLP configuration registers.
+ */
+void tegra30_set_up_pllp(void)
+{
+	struct clk_rst_ctlr *clkrst = (struct clk_rst_ctlr *)NV_PA_CLK_RST_BASE;
+	u32 reg;
+
+	/*
+	 * Based on the Tegra TRM, the system clock (which is the AVP clock) can
+	 * run up to 275MHz. On power on, the default sytem clock source is set
+	 * to PLLP_OUT0. This function sets PLLP's (hence PLLP_OUT0's) rate to
+	 * 408MHz which is beyond system clock's upper limit.
+	 *
+	 * The fix is to set the system clock to CLK_M before initializing PLLP,
+	 * and then switch back to PLLP_OUT4, which has an appropriate divider
+	 * configured, after PLLP has been configured
+	 */
+	set_avp_clock_source(SCLK_SOURCE_CLKM);
+
+	/*
+	 * PLLP output frequency set to 408Mhz
+	 * PLLC output frequency set to 228Mhz
+	 */
+	switch (clock_get_osc_freq()) {
+	case CLOCK_OSC_FREQ_12_0: /* OSC is 12Mhz */
+		clock_set_rate(CLOCK_ID_PERIPH, 408, 12, 0, 8);
+		clock_set_rate(CLOCK_ID_CGENERAL, 456, 12, 1, 8);
+		break;
+
+	case CLOCK_OSC_FREQ_26_0: /* OSC is 26Mhz */
+		clock_set_rate(CLOCK_ID_PERIPH, 408, 26, 0, 8);
+		clock_set_rate(CLOCK_ID_CGENERAL, 600, 26, 0, 8);
+		break;
+
+	case CLOCK_OSC_FREQ_13_0: /* OSC is 13Mhz */
+		clock_set_rate(CLOCK_ID_PERIPH, 408, 13, 0, 8);
+		clock_set_rate(CLOCK_ID_CGENERAL, 600, 13, 0, 8);
+		break;
+	case CLOCK_OSC_FREQ_19_2:
+	default:
+		/*
+		 * These are not supported. It is too early to print a
+		 * message and the UART likely won't work anyway due to the
+		 * oscillator being wrong.
+		 */
+		break;
+	}
+
+	/* Set PLLP_OUT1, 2, 3 & 4 freqs to 9.6, 48, 102 & 204MHz */
+
+	/* OUT1, 2 */
+	/* Assert RSTN before enable */
+	reg = PLLP_OUT2_RSTN_EN | PLLP_OUT1_RSTN_EN;
+	writel(reg, &clkrst->crc_pll[CLOCK_ID_PERIPH].pll_out[0]);
+	/* Set divisor and reenable */
+	reg = (IN_408_OUT_48_DIVISOR << PLLP_OUT2_RATIO)
+		| PLLP_OUT2_OVR | PLLP_OUT2_CLKEN | PLLP_OUT2_RSTN_DIS
+		| (IN_408_OUT_9_6_DIVISOR << PLLP_OUT1_RATIO)
+		| PLLP_OUT1_OVR | PLLP_OUT1_CLKEN | PLLP_OUT1_RSTN_DIS;
+	writel(reg, &clkrst->crc_pll[CLOCK_ID_PERIPH].pll_out[0]);
+
+	/* OUT3, 4 */
+	/* Assert RSTN before enable */
+	reg = PLLP_OUT4_RSTN_EN | PLLP_OUT3_RSTN_EN;
+	writel(reg, &clkrst->crc_pll[CLOCK_ID_PERIPH].pll_out[1]);
+	/* Set divisor and reenable */
+	reg = (IN_408_OUT_204_DIVISOR << PLLP_OUT4_RATIO)
+		| PLLP_OUT4_OVR | PLLP_OUT4_CLKEN | PLLP_OUT4_RSTN_DIS
+		| (IN_408_OUT_102_DIVISOR << PLLP_OUT3_RATIO)
+		| PLLP_OUT3_OVR | PLLP_OUT3_CLKEN | PLLP_OUT3_RSTN_DIS;
+	writel(reg, &clkrst->crc_pll[CLOCK_ID_PERIPH].pll_out[1]);
+
+	set_avp_clock_source(SCLK_SOURCE_PLLP_OUT4);
+}