u-boot/arch/riscv/cpu/ax25/cpu.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2017 Andes Technology Corporation
 * Rick Chen, Andes Technology Corporation <rick@andestech.com>
 */

/* CPU specific code */
#include <common.h>
#include <cpu_func.h>
#include <irq_func.h>
#include <asm/cache.h>
#include <asm/csr.h>

#define CSR_MCACHE_CTL	0x7ca
#define CSR_MMISC_CTL	0x7d0
#define CSR_MARCHID		0xf12

#define V5_MCACHE_CTL_IC_EN_OFFSET      0
#define V5_MCACHE_CTL_DC_EN_OFFSET      1
#define V5_MCACHE_CTL_DC_COHEN_OFFSET	19
#define V5_MCACHE_CTL_DC_COHSTA_OFFSET	20

#define V5_MCACHE_CTL_IC_EN		BIT(V5_MCACHE_CTL_IC_EN_OFFSET)
#define V5_MCACHE_CTL_DC_EN				BIT(V5_MCACHE_CTL_DC_EN_OFFSET)
#define V5_MCACHE_CTL_DC_COHEN_EN       BIT(V5_MCACHE_CTL_DC_COHEN_OFFSET)
#define V5_MCACHE_CTL_DC_COHSTA_EN      BIT(V5_MCACHE_CTL_DC_COHSTA_OFFSET)


/*
 * cleanup_before_linux() is called just before we call linux
 * it prepares the processor for linux
 *
 * we disable interrupt and caches.
 */
int cleanup_before_linux(void)
{
	disable_interrupts();

	/* turn off I/D-cache */
	cache_flush();
	icache_disable();
	dcache_disable();

	return 0;
}

void harts_early_init(void)
{
	if (CONFIG_IS_ENABLED(RISCV_MMODE)) {
		unsigned long long mcache_ctl_val = csr_read(CSR_MCACHE_CTL);

		if (!(mcache_ctl_val & V5_MCACHE_CTL_DC_COHEN_EN))
			mcache_ctl_val |= V5_MCACHE_CTL_DC_COHEN_EN;
		if (!(mcache_ctl_val & V5_MCACHE_CTL_IC_EN))
			mcache_ctl_val |= V5_MCACHE_CTL_IC_EN;
		if (!(mcache_ctl_val & V5_MCACHE_CTL_DC_EN))
			mcache_ctl_val |= V5_MCACHE_CTL_DC_EN;
		csr_write(CSR_MCACHE_CTL, mcache_ctl_val);

		/*
		 * Check DC_COHEN_EN, if cannot write to mcache_ctl,
		 * we assume this bitmap not support L2 CM
		 */
		mcache_ctl_val = csr_read(CSR_MCACHE_CTL);
		if ((mcache_ctl_val & V5_MCACHE_CTL_DC_COHEN_EN)) {
		/* Wait for DC_COHSTA bit be set */
			while (!(mcache_ctl_val & V5_MCACHE_CTL_DC_COHSTA_EN))
				mcache_ctl_val = csr_read(CSR_MCACHE_CTL);
		}
	}
}