diff options
Diffstat (limited to 'drivers/crypto/ccp/tee-dev.c')
| -rw-r--r-- | drivers/crypto/ccp/tee-dev.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/drivers/crypto/ccp/tee-dev.c b/drivers/crypto/ccp/tee-dev.c new file mode 100644 index 000000000000..ccbc2ce59d51 --- /dev/null +++ b/drivers/crypto/ccp/tee-dev.c @@ -0,0 +1,238 @@ +// 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); +} |