arch/arm/mach-tegra/tegra30/cpu.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2010-2014, NVIDIA CORPORATION.  All rights reserved.
 */

#include <log.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#include <asm/arch/flow.h>
#include <asm/arch/tegra.h>
#include <asm/arch-tegra/clk_rst.h>
#include <asm/arch-tegra/pmc.h>
#include <asm/arch-tegra/tegra_i2c.h>
#include <linux/delay.h>
#include "../cpu.h"

/* In case this function is not defined */
__weak void pmic_enable_cpu_vdd(void) {}

static void enable_cpu_power_rail(void)
{
	struct pmc_ctlr *pmc = (struct pmc_ctlr *)NV_PA_PMC_BASE;
	u32 reg;

	debug("enable_cpu_power_rail entry\n");
	reg = readl(&pmc->pmc_cntrl);
	reg |= CPUPWRREQ_OE;
	writel(reg, &pmc->pmc_cntrl);
}

/**
 * The T30 requires some special clock initialization, including setting up
 * the dvc i2c, turning on mselect and selecting the G CPU cluster
 */
void t30_init_clocks(void)
{
	struct clk_rst_ctlr *clkrst =
			(struct clk_rst_ctlr *)NV_PA_CLK_RST_BASE;
	struct flow_ctlr *flow = (struct flow_ctlr *)NV_PA_FLOW_BASE;
	u32 val;

	debug("t30_init_clocks entry\n");
	/* Set active CPU cluster to G */
	clrbits_le32(flow->cluster_control, 1 << 0);

	writel(SUPER_SCLK_ENB_MASK, &clkrst->crc_super_sclk_div);

	val = (0 << CLK_SYS_RATE_HCLK_DISABLE_SHIFT) |
		(1 << CLK_SYS_RATE_AHB_RATE_SHIFT) |
		(0 << CLK_SYS_RATE_PCLK_DISABLE_SHIFT) |
		(0 << CLK_SYS_RATE_APB_RATE_SHIFT);
	writel(val, &clkrst->crc_clk_sys_rate);

	/* Put i2c, mselect in reset and enable clocks */
	reset_set_enable(PERIPH_ID_DVC_I2C, 1);
	clock_set_enable(PERIPH_ID_DVC_I2C, 1);
	reset_set_enable(PERIPH_ID_MSELECT, 1);
	clock_set_enable(PERIPH_ID_MSELECT, 1);

	/* Switch MSELECT clock to PLLP (00) and use a divisor of 2 */
	clock_ll_set_source_divisor(PERIPH_ID_MSELECT, 0, 2);

	/*
	 * Our high-level clock routines are not available prior to
	 * relocation. We use the low-level functions which require a
	 * hard-coded divisor. Use CLK_M with divide by (n + 1 = 17)
	 */
	clock_ll_set_source_divisor(PERIPH_ID_DVC_I2C, 3, 16);

	/*
	 * Give clocks time to stabilize, then take i2c and mselect out of
	 * reset
	 */
	udelay(1000);
	reset_set_enable(PERIPH_ID_DVC_I2C, 0);
	reset_set_enable(PERIPH_ID_MSELECT, 0);
}

static void set_cpu_running(int run)
{
	struct flow_ctlr *flow = (struct flow_ctlr *)NV_PA_FLOW_BASE;

	debug("set_cpu_running entry, run = %d\n", run);
	writel(run ? FLOW_MODE_NONE : FLOW_MODE_STOP, &flow->halt_cpu_events);
}

void start_cpu(u32 reset_vector)
{
	debug("start_cpu entry, reset_vector = %x\n", reset_vector);
	t30_init_clocks();

	/* Enable VDD_CPU */
	enable_cpu_power_rail();
	pmic_enable_cpu_vdd();

	set_cpu_running(0);

	/* Hold the CPUs in reset */
	reset_A9_cpu(1);

	/* Disable the CPU clock */
	enable_cpu_clock(0);

	/* Enable CoreSight */
	clock_enable_coresight(1);

	/*
	 * Set the entry point for CPU execution from reset,
	 *  if it's a non-zero value.
	 */
	if (reset_vector)
		writel(reset_vector, EXCEP_VECTOR_CPU_RESET_VECTOR);

	/* Enable the CPU clock */
	enable_cpu_clock(1);

	/* If the CPU doesn't already have power, power it up */
	powerup_cpu();

	/* Take the CPU out of reset */
	reset_A9_cpu(0);

	set_cpu_running(1);
}