linux/drivers/firmware/qcom_scm.c
Lina Iyer 767b0235dd firmware: qcom: scm: Support cpu power down through SCM
Support powering down the calling cpu, by trapping into SCM. This
termination function triggers the ARM cpu to execute WFI instruction,
causing the power controller to safely power the cpu down.

Caches may be flushed before powering down the cpu. If cache controller
is set to turn off when the cpu is powered down, then the flags argument
indicates to the secure mode to flush its cache lines before executing
WFI.The warm boot reset address for the cpu should be set before the
calling into this function for the cpu to resume.

The original code for the qcom_scm_call_atomic1() comes from a patch by
Stephen Boyd [1]. The function scm_call_atomic1() has been cherry picked
and renamed to match the convention used in this file. Since there are
no users of scm_call_atomic2(), the function is not included.

[1]. https://lkml.org/lkml/2014/8/4/765

Signed-off-by: Stephen Boyd <sboyd@codeauraro.org>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Kumar Gala <galak@codeaurora.org>
2015-03-11 15:15:11 -05:00

495 lines
13 KiB
C

/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
* Copyright (C) 2015 Linaro Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/qcom_scm.h>
#include <asm/outercache.h>
#include <asm/cacheflush.h>
#define QCOM_SCM_ENOMEM -5
#define QCOM_SCM_EOPNOTSUPP -4
#define QCOM_SCM_EINVAL_ADDR -3
#define QCOM_SCM_EINVAL_ARG -2
#define QCOM_SCM_ERROR -1
#define QCOM_SCM_INTERRUPTED 1
#define QCOM_SCM_FLAG_COLDBOOT_CPU0 0x00
#define QCOM_SCM_FLAG_COLDBOOT_CPU1 0x01
#define QCOM_SCM_FLAG_COLDBOOT_CPU2 0x08
#define QCOM_SCM_FLAG_COLDBOOT_CPU3 0x20
#define QCOM_SCM_FLAG_WARMBOOT_CPU0 0x04
#define QCOM_SCM_FLAG_WARMBOOT_CPU1 0x02
#define QCOM_SCM_FLAG_WARMBOOT_CPU2 0x10
#define QCOM_SCM_FLAG_WARMBOOT_CPU3 0x40
struct qcom_scm_entry {
int flag;
void *entry;
};
static struct qcom_scm_entry qcom_scm_wb[] = {
{ .flag = QCOM_SCM_FLAG_WARMBOOT_CPU0 },
{ .flag = QCOM_SCM_FLAG_WARMBOOT_CPU1 },
{ .flag = QCOM_SCM_FLAG_WARMBOOT_CPU2 },
{ .flag = QCOM_SCM_FLAG_WARMBOOT_CPU3 },
};
static DEFINE_MUTEX(qcom_scm_lock);
/**
* struct qcom_scm_command - one SCM command buffer
* @len: total available memory for command and response
* @buf_offset: start of command buffer
* @resp_hdr_offset: start of response buffer
* @id: command to be executed
* @buf: buffer returned from qcom_scm_get_command_buffer()
*
* An SCM command is laid out in memory as follows:
*
* ------------------- <--- struct qcom_scm_command
* | command header |
* ------------------- <--- qcom_scm_get_command_buffer()
* | command buffer |
* ------------------- <--- struct qcom_scm_response and
* | response header | qcom_scm_command_to_response()
* ------------------- <--- qcom_scm_get_response_buffer()
* | response buffer |
* -------------------
*
* There can be arbitrary padding between the headers and buffers so
* you should always use the appropriate qcom_scm_get_*_buffer() routines
* to access the buffers in a safe manner.
*/
struct qcom_scm_command {
__le32 len;
__le32 buf_offset;
__le32 resp_hdr_offset;
__le32 id;
__le32 buf[0];
};
/**
* struct qcom_scm_response - one SCM response buffer
* @len: total available memory for response
* @buf_offset: start of response data relative to start of qcom_scm_response
* @is_complete: indicates if the command has finished processing
*/
struct qcom_scm_response {
__le32 len;
__le32 buf_offset;
__le32 is_complete;
};
/**
* alloc_qcom_scm_command() - Allocate an SCM command
* @cmd_size: size of the command buffer
* @resp_size: size of the response buffer
*
* Allocate an SCM command, including enough room for the command
* and response headers as well as the command and response buffers.
*
* Returns a valid &qcom_scm_command on success or %NULL if the allocation fails.
*/
static struct qcom_scm_command *alloc_qcom_scm_command(size_t cmd_size, size_t resp_size)
{
struct qcom_scm_command *cmd;
size_t len = sizeof(*cmd) + sizeof(struct qcom_scm_response) + cmd_size +
resp_size;
u32 offset;
cmd = kzalloc(PAGE_ALIGN(len), GFP_KERNEL);
if (cmd) {
cmd->len = cpu_to_le32(len);
offset = offsetof(struct qcom_scm_command, buf);
cmd->buf_offset = cpu_to_le32(offset);
cmd->resp_hdr_offset = cpu_to_le32(offset + cmd_size);
}
return cmd;
}
/**
* free_qcom_scm_command() - Free an SCM command
* @cmd: command to free
*
* Free an SCM command.
*/
static inline void free_qcom_scm_command(struct qcom_scm_command *cmd)
{
kfree(cmd);
}
/**
* qcom_scm_command_to_response() - Get a pointer to a qcom_scm_response
* @cmd: command
*
* Returns a pointer to a response for a command.
*/
static inline struct qcom_scm_response *qcom_scm_command_to_response(
const struct qcom_scm_command *cmd)
{
return (void *)cmd + le32_to_cpu(cmd->resp_hdr_offset);
}
/**
* qcom_scm_get_command_buffer() - Get a pointer to a command buffer
* @cmd: command
*
* Returns a pointer to the command buffer of a command.
*/
static inline void *qcom_scm_get_command_buffer(const struct qcom_scm_command *cmd)
{
return (void *)cmd->buf;
}
/**
* qcom_scm_get_response_buffer() - Get a pointer to a response buffer
* @rsp: response
*
* Returns a pointer to a response buffer of a response.
*/
static inline void *qcom_scm_get_response_buffer(const struct qcom_scm_response *rsp)
{
return (void *)rsp + le32_to_cpu(rsp->buf_offset);
}
static int qcom_scm_remap_error(int err)
{
pr_err("qcom_scm_call failed with error code %d\n", err);
switch (err) {
case QCOM_SCM_ERROR:
return -EIO;
case QCOM_SCM_EINVAL_ADDR:
case QCOM_SCM_EINVAL_ARG:
return -EINVAL;
case QCOM_SCM_EOPNOTSUPP:
return -EOPNOTSUPP;
case QCOM_SCM_ENOMEM:
return -ENOMEM;
}
return -EINVAL;
}
static u32 smc(u32 cmd_addr)
{
int context_id;
register u32 r0 asm("r0") = 1;
register u32 r1 asm("r1") = (u32)&context_id;
register u32 r2 asm("r2") = cmd_addr;
do {
asm volatile(
__asmeq("%0", "r0")
__asmeq("%1", "r0")
__asmeq("%2", "r1")
__asmeq("%3", "r2")
#ifdef REQUIRES_SEC
".arch_extension sec\n"
#endif
"smc #0 @ switch to secure world\n"
: "=r" (r0)
: "r" (r0), "r" (r1), "r" (r2)
: "r3");
} while (r0 == QCOM_SCM_INTERRUPTED);
return r0;
}
static int __qcom_scm_call(const struct qcom_scm_command *cmd)
{
int ret;
u32 cmd_addr = virt_to_phys(cmd);
/*
* Flush the command buffer so that the secure world sees
* the correct data.
*/
__cpuc_flush_dcache_area((void *)cmd, cmd->len);
outer_flush_range(cmd_addr, cmd_addr + cmd->len);
ret = smc(cmd_addr);
if (ret < 0)
ret = qcom_scm_remap_error(ret);
return ret;
}
static void qcom_scm_inv_range(unsigned long start, unsigned long end)
{
u32 cacheline_size, ctr;
asm volatile("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
cacheline_size = 4 << ((ctr >> 16) & 0xf);
start = round_down(start, cacheline_size);
end = round_up(end, cacheline_size);
outer_inv_range(start, end);
while (start < end) {
asm ("mcr p15, 0, %0, c7, c6, 1" : : "r" (start)
: "memory");
start += cacheline_size;
}
dsb();
isb();
}
/**
* qcom_scm_call() - Send an SCM command
* @svc_id: service identifier
* @cmd_id: command identifier
* @cmd_buf: command buffer
* @cmd_len: length of the command buffer
* @resp_buf: response buffer
* @resp_len: length of the response buffer
*
* Sends a command to the SCM and waits for the command to finish processing.
*
* A note on cache maintenance:
* Note that any buffers that are expected to be accessed by the secure world
* must be flushed before invoking qcom_scm_call and invalidated in the cache
* immediately after qcom_scm_call returns. Cache maintenance on the command
* and response buffers is taken care of by qcom_scm_call; however, callers are
* responsible for any other cached buffers passed over to the secure world.
*/
static int qcom_scm_call(u32 svc_id, u32 cmd_id, const void *cmd_buf,
size_t cmd_len, void *resp_buf, size_t resp_len)
{
int ret;
struct qcom_scm_command *cmd;
struct qcom_scm_response *rsp;
unsigned long start, end;
cmd = alloc_qcom_scm_command(cmd_len, resp_len);
if (!cmd)
return -ENOMEM;
cmd->id = cpu_to_le32((svc_id << 10) | cmd_id);
if (cmd_buf)
memcpy(qcom_scm_get_command_buffer(cmd), cmd_buf, cmd_len);
mutex_lock(&qcom_scm_lock);
ret = __qcom_scm_call(cmd);
mutex_unlock(&qcom_scm_lock);
if (ret)
goto out;
rsp = qcom_scm_command_to_response(cmd);
start = (unsigned long)rsp;
do {
qcom_scm_inv_range(start, start + sizeof(*rsp));
} while (!rsp->is_complete);
end = (unsigned long)qcom_scm_get_response_buffer(rsp) + resp_len;
qcom_scm_inv_range(start, end);
if (resp_buf)
memcpy(resp_buf, qcom_scm_get_response_buffer(rsp), resp_len);
out:
free_qcom_scm_command(cmd);
return ret;
}
#define SCM_CLASS_REGISTER (0x2 << 8)
#define SCM_MASK_IRQS BIT(5)
#define SCM_ATOMIC(svc, cmd, n) (((((svc) << 10)|((cmd) & 0x3ff)) << 12) | \
SCM_CLASS_REGISTER | \
SCM_MASK_IRQS | \
(n & 0xf))
/**
* qcom_scm_call_atomic1() - Send an atomic SCM command with one argument
* @svc_id: service identifier
* @cmd_id: command identifier
* @arg1: first argument
*
* This shall only be used with commands that are guaranteed to be
* uninterruptable, atomic and SMP safe.
*/
static s32 qcom_scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
{
int context_id;
register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 1);
register u32 r1 asm("r1") = (u32)&context_id;
register u32 r2 asm("r2") = arg1;
asm volatile(
__asmeq("%0", "r0")
__asmeq("%1", "r0")
__asmeq("%2", "r1")
__asmeq("%3", "r2")
#ifdef REQUIRES_SEC
".arch_extension sec\n"
#endif
"smc #0 @ switch to secure world\n"
: "=r" (r0)
: "r" (r0), "r" (r1), "r" (r2)
: "r3");
return r0;
}
u32 qcom_scm_get_version(void)
{
int context_id;
static u32 version = -1;
register u32 r0 asm("r0");
register u32 r1 asm("r1");
if (version != -1)
return version;
mutex_lock(&qcom_scm_lock);
r0 = 0x1 << 8;
r1 = (u32)&context_id;
do {
asm volatile(
__asmeq("%0", "r0")
__asmeq("%1", "r1")
__asmeq("%2", "r0")
__asmeq("%3", "r1")
#ifdef REQUIRES_SEC
".arch_extension sec\n"
#endif
"smc #0 @ switch to secure world\n"
: "=r" (r0), "=r" (r1)
: "r" (r0), "r" (r1)
: "r2", "r3");
} while (r0 == QCOM_SCM_INTERRUPTED);
version = r1;
mutex_unlock(&qcom_scm_lock);
return version;
}
EXPORT_SYMBOL(qcom_scm_get_version);
#define QCOM_SCM_SVC_BOOT 0x1
#define QCOM_SCM_BOOT_ADDR 0x1
/*
* Set the cold/warm boot address for one of the CPU cores.
*/
static int qcom_scm_set_boot_addr(u32 addr, int flags)
{
struct {
__le32 flags;
__le32 addr;
} cmd;
cmd.addr = cpu_to_le32(addr);
cmd.flags = cpu_to_le32(flags);
return qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
&cmd, sizeof(cmd), NULL, 0);
}
/**
* qcom_scm_set_cold_boot_addr() - Set the cold boot address for cpus
* @entry: Entry point function for the cpus
* @cpus: The cpumask of cpus that will use the entry point
*
* Set the cold boot address of the cpus. Any cpu outside the supported
* range would be removed from the cpu present mask.
*/
int qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus)
{
int flags = 0;
int cpu;
int scm_cb_flags[] = {
QCOM_SCM_FLAG_COLDBOOT_CPU0,
QCOM_SCM_FLAG_COLDBOOT_CPU1,
QCOM_SCM_FLAG_COLDBOOT_CPU2,
QCOM_SCM_FLAG_COLDBOOT_CPU3,
};
if (!cpus || (cpus && cpumask_empty(cpus)))
return -EINVAL;
for_each_cpu(cpu, cpus) {
if (cpu < ARRAY_SIZE(scm_cb_flags))
flags |= scm_cb_flags[cpu];
else
set_cpu_present(cpu, false);
}
return qcom_scm_set_boot_addr(virt_to_phys(entry), flags);
}
EXPORT_SYMBOL(qcom_scm_set_cold_boot_addr);
/**
* qcom_scm_set_warm_boot_addr() - Set the warm boot address for cpus
* @entry: Entry point function for the cpus
* @cpus: The cpumask of cpus that will use the entry point
*
* Set the Linux entry point for the SCM to transfer control to when coming
* out of a power down. CPU power down may be executed on cpuidle or hotplug.
*/
int qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
{
int ret;
int flags = 0;
int cpu;
/*
* Reassign only if we are switching from hotplug entry point
* to cpuidle entry point or vice versa.
*/
for_each_cpu(cpu, cpus) {
if (entry == qcom_scm_wb[cpu].entry)
continue;
flags |= qcom_scm_wb[cpu].flag;
}
/* No change in entry function */
if (!flags)
return 0;
ret = qcom_scm_set_boot_addr(virt_to_phys(entry), flags);
if (!ret) {
for_each_cpu(cpu, cpus)
qcom_scm_wb[cpu].entry = entry;
}
return ret;
}
EXPORT_SYMBOL(qcom_scm_set_warm_boot_addr);
#define QCOM_SCM_CMD_TERMINATE_PC 0x2
#define QCOM_SCM_FLUSH_FLAG_MASK 0x3
/**
* qcom_scm_cpu_power_down() - Power down the cpu
* @flags - Flags to flush cache
*
* This is an end point to power down cpu. If there was a pending interrupt,
* the control would return from this function, otherwise, the cpu jumps to the
* warm boot entry point set for this cpu upon reset.
*/
void qcom_scm_cpu_power_down(u32 flags)
{
qcom_scm_call_atomic1(QCOM_SCM_SVC_BOOT, QCOM_SCM_CMD_TERMINATE_PC,
flags & QCOM_SCM_FLUSH_FLAG_MASK);
}
EXPORT_SYMBOL(qcom_scm_cpu_power_down);