blob: bcb81fef4211826f99ea6cd251f7ea645b66fff4 [file] [log] [blame]
// SPDX-License-Identifier: MIT
/*
* AMD Trusted Execution Environment (TEE) interface
*
* Author: Rijo Thomas <Rijo-john.Thomas@amd.com>
* Author: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
*
* Copyright 2019 Advanced Micro Devices, Inc.
*/
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/gfp.h>
#include <linux/psp-sev.h>
#include <linux/psp-tee.h>
#include "psp-dev.h"
#include "tee-dev.h"
static bool psp_dead;
static int tee_alloc_ring(struct psp_tee_device *tee, int ring_size)
{
struct ring_buf_manager *rb_mgr = &tee->rb_mgr;
void *start_addr;
if (!ring_size)
return -EINVAL;
/* We need actual physical address instead of DMA address, since
* Trusted OS running on AMD Secure Processor will map this region
*/
start_addr = (void *)__get_free_pages(GFP_KERNEL, get_order(ring_size));
if (!start_addr)
return -ENOMEM;
memset(start_addr, 0x0, ring_size);
rb_mgr->ring_start = start_addr;
rb_mgr->ring_size = ring_size;
rb_mgr->ring_pa = __psp_pa(start_addr);
mutex_init(&rb_mgr->mutex);
return 0;
}
static void tee_free_ring(struct psp_tee_device *tee)
{
struct ring_buf_manager *rb_mgr = &tee->rb_mgr;
if (!rb_mgr->ring_start)
return;
free_pages((unsigned long)rb_mgr->ring_start,
get_order(rb_mgr->ring_size));
rb_mgr->ring_start = NULL;
rb_mgr->ring_size = 0;
rb_mgr->ring_pa = 0;
mutex_destroy(&rb_mgr->mutex);
}
static int tee_wait_cmd_poll(struct psp_tee_device *tee, unsigned int timeout,
unsigned int *reg)
{
/* ~10ms sleep per loop => nloop = timeout * 100 */
int nloop = timeout * 100;
while (--nloop) {
*reg = ioread32(tee->io_regs + tee->vdata->cmdresp_reg);
if (*reg & PSP_CMDRESP_RESP)
return 0;
usleep_range(10000, 10100);
}
dev_err(tee->dev, "tee: command timed out, disabling PSP\n");
psp_dead = true;
return -ETIMEDOUT;
}
static
struct tee_init_ring_cmd *tee_alloc_cmd_buffer(struct psp_tee_device *tee)
{
struct tee_init_ring_cmd *cmd;
cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
if (!cmd)
return NULL;
cmd->hi_addr = upper_32_bits(tee->rb_mgr.ring_pa);
cmd->low_addr = lower_32_bits(tee->rb_mgr.ring_pa);
cmd->size = tee->rb_mgr.ring_size;
dev_dbg(tee->dev, "tee: ring address: high = 0x%x low = 0x%x size = %u\n",
cmd->hi_addr, cmd->low_addr, cmd->size);
return cmd;
}
static inline void tee_free_cmd_buffer(struct tee_init_ring_cmd *cmd)
{
kfree(cmd);
}
static int tee_init_ring(struct psp_tee_device *tee)
{
int ring_size = MAX_RING_BUFFER_ENTRIES * sizeof(struct tee_ring_cmd);
struct tee_init_ring_cmd *cmd;
phys_addr_t cmd_buffer;
unsigned int reg;
int ret;
BUILD_BUG_ON(sizeof(struct tee_ring_cmd) != 1024);
ret = tee_alloc_ring(tee, ring_size);
if (ret) {
dev_err(tee->dev, "tee: ring allocation failed %d\n", ret);
return ret;
}
tee->rb_mgr.wptr = 0;
cmd = tee_alloc_cmd_buffer(tee);
if (!cmd) {
tee_free_ring(tee);
return -ENOMEM;
}
cmd_buffer = __psp_pa((void *)cmd);
/* Send command buffer details to Trusted OS by writing to
* CPU-PSP message registers
*/
iowrite32(lower_32_bits(cmd_buffer),
tee->io_regs + tee->vdata->cmdbuff_addr_lo_reg);
iowrite32(upper_32_bits(cmd_buffer),
tee->io_regs + tee->vdata->cmdbuff_addr_hi_reg);
iowrite32(TEE_RING_INIT_CMD,
tee->io_regs + tee->vdata->cmdresp_reg);
ret = tee_wait_cmd_poll(tee, TEE_DEFAULT_TIMEOUT, &reg);
if (ret) {
dev_err(tee->dev, "tee: ring init command timed out\n");
tee_free_ring(tee);
goto free_buf;
}
if (reg & PSP_CMDRESP_ERR_MASK) {
dev_err(tee->dev, "tee: ring init command failed (%#010x)\n",
reg & PSP_CMDRESP_ERR_MASK);
tee_free_ring(tee);
ret = -EIO;
}
free_buf:
tee_free_cmd_buffer(cmd);
return ret;
}
static void tee_destroy_ring(struct psp_tee_device *tee)
{
unsigned int reg;
int ret;
if (!tee->rb_mgr.ring_start)
return;
if (psp_dead)
goto free_ring;
iowrite32(TEE_RING_DESTROY_CMD,
tee->io_regs + tee->vdata->cmdresp_reg);
ret = tee_wait_cmd_poll(tee, TEE_DEFAULT_TIMEOUT, &reg);
if (ret) {
dev_err(tee->dev, "tee: ring destroy command timed out\n");
} else if (reg & PSP_CMDRESP_ERR_MASK) {
dev_err(tee->dev, "tee: ring destroy command failed (%#010x)\n",
reg & PSP_CMDRESP_ERR_MASK);
}
free_ring:
tee_free_ring(tee);
}
int tee_dev_init(struct psp_device *psp)
{
struct device *dev = psp->dev;
struct psp_tee_device *tee;
int ret;
ret = -ENOMEM;
tee = devm_kzalloc(dev, sizeof(*tee), GFP_KERNEL);
if (!tee)
goto e_err;
psp->tee_data = tee;
tee->dev = dev;
tee->psp = psp;
tee->io_regs = psp->io_regs;
tee->vdata = (struct tee_vdata *)psp->vdata->tee;
if (!tee->vdata) {
ret = -ENODEV;
dev_err(dev, "tee: missing driver data\n");
goto e_err;
}
ret = tee_init_ring(tee);
if (ret) {
dev_err(dev, "tee: failed to init ring buffer\n");
goto e_err;
}
dev_notice(dev, "tee enabled\n");
return 0;
e_err:
psp->tee_data = NULL;
dev_notice(dev, "tee initialization failed\n");
return ret;
}
void tee_dev_destroy(struct psp_device *psp)
{
struct psp_tee_device *tee = psp->tee_data;
if (!tee)
return;
tee_destroy_ring(tee);
}
static int tee_submit_cmd(struct psp_tee_device *tee, enum tee_cmd_id cmd_id,
void *buf, size_t len, struct tee_ring_cmd **resp)
{
struct tee_ring_cmd *cmd;
int nloop = 1000, ret = 0;
u32 rptr;
*resp = NULL;
mutex_lock(&tee->rb_mgr.mutex);
/* Loop until empty entry found in ring buffer */
do {
/* Get pointer to ring buffer command entry */
cmd = (struct tee_ring_cmd *)
(tee->rb_mgr.ring_start + tee->rb_mgr.wptr);
rptr = ioread32(tee->io_regs + tee->vdata->ring_rptr_reg);
/* Check if ring buffer is full or command entry is waiting
* for response from TEE
*/
if (!(tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr ||
cmd->flag == CMD_WAITING_FOR_RESPONSE))
break;
dev_dbg(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u\n",
rptr, tee->rb_mgr.wptr);
/* Wait if ring buffer is full or TEE is processing data */
mutex_unlock(&tee->rb_mgr.mutex);
schedule_timeout_interruptible(msecs_to_jiffies(10));
mutex_lock(&tee->rb_mgr.mutex);
} while (--nloop);
if (!nloop &&
(tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr ||
cmd->flag == CMD_WAITING_FOR_RESPONSE)) {
dev_err(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u response flag %u\n",
rptr, tee->rb_mgr.wptr, cmd->flag);
ret = -EBUSY;
goto unlock;
}
/* Do not submit command if PSP got disabled while processing any
* command in another thread
*/
if (psp_dead) {
ret = -EBUSY;
goto unlock;
}
/* Write command data into ring buffer */
cmd->cmd_id = cmd_id;
cmd->cmd_state = TEE_CMD_STATE_INIT;
memset(&cmd->buf[0], 0, sizeof(cmd->buf));
memcpy(&cmd->buf[0], buf, len);
/* Indicate driver is waiting for response */
cmd->flag = CMD_WAITING_FOR_RESPONSE;
/* Update local copy of write pointer */
tee->rb_mgr.wptr += sizeof(struct tee_ring_cmd);
if (tee->rb_mgr.wptr >= tee->rb_mgr.ring_size)
tee->rb_mgr.wptr = 0;
/* Trigger interrupt to Trusted OS */
iowrite32(tee->rb_mgr.wptr, tee->io_regs + tee->vdata->ring_wptr_reg);
/* The response is provided by Trusted OS in same
* location as submitted data entry within ring buffer.
*/
*resp = cmd;
unlock:
mutex_unlock(&tee->rb_mgr.mutex);
return ret;
}
static int tee_wait_cmd_completion(struct psp_tee_device *tee,
struct tee_ring_cmd *resp,
unsigned int timeout)
{
/* ~5ms sleep per loop => nloop = timeout * 200 */
int nloop = timeout * 200;
while (--nloop) {
if (resp->cmd_state == TEE_CMD_STATE_COMPLETED)
return 0;
usleep_range(5000, 5100);
}
dev_err(tee->dev, "tee: command 0x%x timed out, disabling PSP\n",
resp->cmd_id);
psp_dead = true;
return -ETIMEDOUT;
}
int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, size_t len,
u32 *status)
{
struct psp_device *psp = psp_get_master_device();
struct psp_tee_device *tee;
struct tee_ring_cmd *resp;
int ret;
if (!buf || !status || !len || len > sizeof(resp->buf))
return -EINVAL;
*status = 0;
if (!psp || !psp->tee_data)
return -ENODEV;
if (psp_dead)
return -EBUSY;
tee = psp->tee_data;
ret = tee_submit_cmd(tee, cmd_id, buf, len, &resp);
if (ret)
return ret;
ret = tee_wait_cmd_completion(tee, resp, TEE_DEFAULT_TIMEOUT);
if (ret) {
resp->flag = CMD_RESPONSE_TIMEDOUT;
return ret;
}
memcpy(buf, &resp->buf[0], len);
*status = resp->status;
resp->flag = CMD_RESPONSE_COPIED;
return 0;
}
EXPORT_SYMBOL(psp_tee_process_cmd);
int psp_check_tee_status(void)
{
struct psp_device *psp = psp_get_master_device();
if (!psp || !psp->tee_data)
return -ENODEV;
return 0;
}
EXPORT_SYMBOL(psp_check_tee_status);