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// 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 "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;
rb_mgr->ring_start = start_addr;
rb_mgr->ring_size = ring_size;
rb_mgr->ring_pa = __psp_pa(start_addr);
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;
}
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, ®);
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, ®);
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);
}
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