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/*
* 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"
static u32 bcm_smc_buffer_phys; /* physical address */
static void __iomem *bcm_smc_buffer; /* virtual address */
struct bcm_kona_smc_data {
unsigned service_id;
unsigned arg0;
unsigned arg1;
unsigned arg2;
unsigned arg3;
unsigned result;
};
static const struct of_device_id bcm_kona_smc_ids[] __initconst = {
{.compatible = "brcm,kona-smc"},
{.compatible = "bcm,kona-smc"}, /* deprecated name */
{},
};
/* Map in the args buffer area */
int __init bcm_kona_smc_init(void)
{
struct device_node *node;
const __be32 *prop_val;
u64 prop_size = 0;
unsigned long buffer_size;
u32 buffer_phys;
/* Read buffer addr and size from the device tree node */
node = of_find_matching_node(NULL, bcm_kona_smc_ids);
if (!node)
return -ENODEV;
prop_val = of_get_address(node, 0, &prop_size, NULL);
of_node_put(node);
if (!prop_val)
return -EINVAL;
/* We assume space for four 32-bit arguments */
if (prop_size < 4 * sizeof(u32) || prop_size > (u64)ULONG_MAX)
return -EINVAL;
buffer_size = (unsigned long)prop_size;
buffer_phys = be32_to_cpup(prop_val);
if (!buffer_phys)
return -EINVAL;
bcm_smc_buffer = ioremap(buffer_phys, buffer_size);
if (!bcm_smc_buffer)
return -ENOMEM;
bcm_smc_buffer_phys = buffer_phys;
pr_info("Kona Secure API initialized\n");
return 0;
}
/*
* int bcm_kona_do_smc(u32 service_id, u32 buffer_addr)
*
* Only core 0 can run the secure monitor code. If an "smc" request
* is initiated on a different core it must be redirected to core 0
* for execution. We rely on the caller to handle this.
*
* Each "smc" request supplies a service id and the address of a
* buffer containing parameters related to the service to be
* performed. A flags value defines the behavior of the level 2
* cache and interrupt handling while the secure monitor executes.
*
* Parameters to the "smc" request are passed in r4-r6 as follows:
* r4 service id
* r5 flags (SEC_ROM_*)
* r6 physical address of buffer with other parameters
*
* Execution of an "smc" request produces two distinct results.
*
* First, the secure monitor call itself (regardless of the specific
* service request) can succeed, or can produce an error. When an
* "smc" request completes this value is found in r12; it should
* always be SEC_EXIT_NORMAL.
*
* In addition, the particular service performed produces a result.
* The values that should be expected depend on the service. We
* therefore return this value to the caller, so it can handle the
* request result appropriately. This result value is found in r0
* when the "smc" request completes.
*/
static int bcm_kona_do_smc(u32 service_id, u32 buffer_phys)
{
register u32 ip asm("ip"); /* Also called r12 */
register u32 r0 asm("r0");
register u32 r4 asm("r4");
register u32 r5 asm("r5");
register u32 r6 asm("r6");
r4 = service_id;
r5 = 0x3; /* Keep IRQ and FIQ off in SM */
r6 = buffer_phys;
asm volatile (
/* Make sure we got the registers we want */
__asmeq("%0", "ip")
__asmeq("%1", "r0")
__asmeq("%2", "r4")
__asmeq("%3", "r5")
__asmeq("%4", "r6")
".arch_extension sec\n"
" smc #0\n"
: "=r" (ip), "=r" (r0)
: "r" (r4), "r" (r5), "r" (r6)
: "r1", "r2", "r3", "r7", "lr");
BUG_ON(ip != SEC_EXIT_NORMAL);
return r0;
}
/* __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 __iomem *args = bcm_smc_buffer;
BUG_ON(smp_processor_id() != 0);
BUG_ON(!args);
/* Copy the four 32 bit argument values into the bounce area */
writel_relaxed(data->arg0, args++);
writel_relaxed(data->arg1, args++);
writel_relaxed(data->arg2, args++);
writel(data->arg3, args);
/* Flush caches for input data passed to Secure Monitor */
flush_cache_all();
/* Trap into Secure Monitor and record the request result */
data->result = bcm_kona_do_smc(data->service_id, bcm_smc_buffer_phys);
}
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;
data.result = 0;
/*
* Due to a limitation of the secure monitor, we must use the SMP
* infrastructure to forward all secure monitor calls to Core 0.
*/
smp_call_function_single(0, __bcm_kona_smc, &data, 1);
return data.result;
}
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