diff options
Diffstat (limited to 'arch/arm/mach-bcm/bcm_kona_smc.c')
| -rw-r--r-- | arch/arm/mach-bcm/bcm_kona_smc.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/arch/arm/mach-bcm/bcm_kona_smc.c b/arch/arm/mach-bcm/bcm_kona_smc.c new file mode 100644 index 000000000..513efea65 --- /dev/null +++ b/arch/arm/mach-bcm/bcm_kona_smc.c @@ -0,0 +1,181 @@ +/* + * 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; +} |