xref: /openbmc/linux/arch/arm/mach-bcm/bcm_kona_smc.c (revision b8eb35fd594aa5b635e329d5c8efab8aaceb8619)

/*
 * Copyright (C) 2013 Broadcom Corporation
 *
 * 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.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <stdarg.h>
#include <linux/smp.h>
#include <linux/io.h>
#include <linux/ioport.h>

#include <asm/cacheflush.h>
#include <linux/of_address.h>

#include "bcm_kona_smc.h"

struct secure_bridge_data {
	void __iomem *bounce;		/* virtual address */
	u32 __iomem buffer_addr;	/* physical address */
	int initialized;
} bridge_data;

struct bcm_kona_smc_data {
	unsigned service_id;
	unsigned arg0;
	unsigned arg1;
	unsigned arg2;
	unsigned arg3;
};

static const struct of_device_id bcm_kona_smc_ids[] __initconst = {
	{.compatible = "bcm,kona-smc"},
	{},
};

/* Map in the bounce area */
void bcm_kona_smc_init(void)
{
	struct device_node *node;

	/* Read buffer addr and size from the device tree node */
	node = of_find_matching_node(NULL, bcm_kona_smc_ids);
	BUG_ON(!node);

	/* Don't care about size or flags of the DT node */
	bridge_data.buffer_addr =
		be32_to_cpu(*of_get_address(node, 0, NULL, NULL));
	BUG_ON(!bridge_data.buffer_addr);

	bridge_data.bounce = of_iomap(node, 0);
	BUG_ON(!bridge_data.bounce);

	bridge_data.initialized = 1;

	pr_info("Secure API initialized!\n");
}

/* __bcm_kona_smc() should only run on CPU 0, with pre-emption disabled */
static void __bcm_kona_smc(void *info)
{
	struct bcm_kona_smc_data *data = info;
	u32 *args = bridge_data.bounce;
	int rc = 0;

	/* Must run on CPU 0 */
	BUG_ON(smp_processor_id() != 0);

	/* Check map in the bounce area */
	BUG_ON(!bridge_data.initialized);

	/* Copy one 32 bit word into the bounce area */
	args[0] = data->arg0;
	args[1] = data->arg1;
	args[2] = data->arg2;
	args[3] = data->arg3;

	/* Flush caches for input data passed to Secure Monitor */
	if (data->service_id != SSAPI_BRCM_START_VC_CORE)
		flush_cache_all();

	/* Trap into Secure Monitor */
	rc = bcm_kona_smc_asm(data->service_id, bridge_data.buffer_addr);

	if (rc != SEC_ROM_RET_OK)
		pr_err("Secure Monitor call failed (0x%x)!\n", rc);
}

unsigned bcm_kona_smc(unsigned service_id, unsigned arg0, unsigned arg1,
		  unsigned arg2, unsigned arg3)
{
	struct bcm_kona_smc_data data;

	data.service_id = service_id;
	data.arg0 = arg0;
	data.arg1 = arg1;
	data.arg2 = arg2;
	data.arg3 = arg3;

	/*
	 * Due to a limitation of the secure monitor, we must use the SMP
	 * infrastructure to forward all secure monitor calls to Core 0.
	 */
	if (get_cpu() != 0)
		smp_call_function_single(0, __bcm_kona_smc, (void *)&data, 1);
	else
		__bcm_kona_smc(&data);

	put_cpu();

	return 0;
}