Re: [RFC PATCH 4/5] crypto: ccp - add TEE support for Raven Ridge

[Thomas, Rijo-john]

Hello Ard,

On 23/10/19 5:19 PM, Ard Biesheuvel wrote:
> (+ Jens)
> 
> On Wed, 23 Oct 2019 at 13:27, Thomas, Rijo-john
> <Rijo-john.Thomas@xxxxxxx> wrote:
>>
>> Adds a PCI device entry for Raven Ridge. Raven Ridge is an APU with a
>> dedicated AMD Secure Processor having Trusted Execution Environment (TEE)
>> support. The TEE provides a secure environment for running Trusted
>> Applications (TAs) which implement security-sensitive parts of a feature.
>>
>> This patch configures AMD Secure Processor's TEE interface by initializing
>> a ring buffer (shared memory between Rich OS and Trusted OS) which can hold
>> multiple command buffer entries. The TEE interface is facilitated by a set
>> of CPU to PSP mailbox registers.
>>
>> The next patch will address how commands are submitted to the ring buffer.
>>
>> Signed-off-by: Rijo Thomas <Rijo-john.Thomas@xxxxxxx>
>> Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@xxxxxxx>
>> ---
>>  drivers/crypto/ccp/Makefile  |   3 +-
>>  drivers/crypto/ccp/psp-dev.c |  74 +++++++++++++-
>>  drivers/crypto/ccp/psp-dev.h |   8 ++
>>  drivers/crypto/ccp/sp-dev.h  |  11 +-
>>  drivers/crypto/ccp/sp-pci.c  |  27 ++++-
>>  drivers/crypto/ccp/tee-dev.c | 237 +++++++++++++++++++++++++++++++++++++++++++
>>  drivers/crypto/ccp/tee-dev.h | 108 ++++++++++++++++++++
>>  7 files changed, 461 insertions(+), 7 deletions(-)
>>  create mode 100644 drivers/crypto/ccp/tee-dev.c
>>  create mode 100644 drivers/crypto/ccp/tee-dev.h
>>
> 
> How does this patch tie into the TEE subsystem we have in drivers/tee?
> 
> 

In the next patch in this series:

crypto: ccp - provide in-kernel API to submit TEE commands

Link : https://patchwork.kernel.org/patch/11206441/

we introduce an API psp_tee_process_cmd(), which will be called by AMD-TEE
driver. The AMD-TEE drivers registers itself with the TEE subsystem and uses
psp_tee_process_cmd() to submit command buffers for processing by Trusted OS
running on AMD Secure Processor.

The AMD-TEE driver is introduced as a separate patchset and can be found here:
https://lkml.org/lkml/2019/10/23/457

Thanks,
Rijo

> 
> 
>> diff --git a/drivers/crypto/ccp/Makefile b/drivers/crypto/ccp/Makefile
>> index 3b29ea4..db362fe 100644
>> --- a/drivers/crypto/ccp/Makefile
>> +++ b/drivers/crypto/ccp/Makefile
>> @@ -9,7 +9,8 @@ ccp-$(CONFIG_CRYPTO_DEV_SP_CCP) += ccp-dev.o \
>>  ccp-$(CONFIG_CRYPTO_DEV_CCP_DEBUGFS) += ccp-debugfs.o
>>  ccp-$(CONFIG_PCI) += sp-pci.o
>>  ccp-$(CONFIG_CRYPTO_DEV_SP_PSP) += psp-dev.o \
>> -                                   sev-dev.o
>> +                                   sev-dev.o \
>> +                                   tee-dev.o
>>
>>  obj-$(CONFIG_CRYPTO_DEV_CCP_CRYPTO) += ccp-crypto.o
>>  ccp-crypto-objs := ccp-crypto-main.o \
>> diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
>> index ef8affa..90bcd5f 100644
>> --- a/drivers/crypto/ccp/psp-dev.c
>> +++ b/drivers/crypto/ccp/psp-dev.c
>> @@ -13,6 +13,7 @@
>>  #include "sp-dev.h"
>>  #include "psp-dev.h"
>>  #include "sev-dev.h"
>> +#include "tee-dev.h"
>>
>>  struct psp_device *psp_master;
>>
>> @@ -45,6 +46,9 @@ static irqreturn_t psp_irq_handler(int irq, void *data)
>>         if (status) {
>>                 if (psp->sev_irq_handler)
>>                         psp->sev_irq_handler(irq, psp->sev_irq_data, status);
>> +
>> +               if (psp->tee_irq_handler)
>> +                       psp->tee_irq_handler(irq, psp->tee_irq_data, status);
>>         }
>>
>>         /* Clear the interrupt status by writing the same value we read. */
>> @@ -53,10 +57,11 @@ static irqreturn_t psp_irq_handler(int irq, void *data)
>>         return IRQ_HANDLED;
>>  }
>>
>> -static int psp_check_sev_support(struct psp_device *psp)
>> +static int psp_check_sev_support(struct psp_device *psp,
>> +                                unsigned int capability)
>>  {
>>         /* Check if device supports SEV feature */
>> -       if (!(ioread32(psp->io_regs + psp->vdata->feature_reg) & 1)) {
>> +       if (!(capability & 1)) {
>>                 dev_dbg(psp->dev, "psp does not support SEV\n");
>>                 return -ENODEV;
>>         }
>> @@ -64,10 +69,54 @@ static int psp_check_sev_support(struct psp_device *psp)
>>         return 0;
>>  }
>>
>> +static int psp_check_tee_support(struct psp_device *psp,
>> +                                unsigned int capability)
>> +{
>> +       /* Check if device supports TEE feature */
>> +       if (!(capability & 2)) {
>> +               dev_dbg(psp->dev, "psp does not support TEE\n");
>> +               return -ENODEV;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int psp_check_support(struct psp_device *psp, unsigned int capability)
>> +{
>> +       int sev_support = psp_check_sev_support(psp, capability);
>> +       int tee_support = psp_check_tee_support(psp, capability);
>> +
>> +       /* Check if device supprts SEV and TEE feature */
>> +       if (sev_support && tee_support)
>> +               return -ENODEV;
>> +
>> +       return 0;
>> +}
>> +
>> +static int psp_init(struct psp_device *psp, unsigned int capability)
>> +{
>> +       int ret;
>> +
>> +       if (!psp_check_sev_support(psp, capability)) {
>> +               ret = sev_dev_init(psp);
>> +               if (ret)
>> +                       return ret;
>> +       }
>> +
>> +       if (!psp_check_tee_support(psp, capability)) {
>> +               ret = tee_dev_init(psp);
>> +               if (ret)
>> +                       return ret;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>>  int psp_dev_init(struct sp_device *sp)
>>  {
>>         struct device *dev = sp->dev;
>>         struct psp_device *psp;
>> +       unsigned int capability;
>>         int ret;
>>
>>         ret = -ENOMEM;
>> @@ -86,7 +135,10 @@ int psp_dev_init(struct sp_device *sp)
>>
>>         psp->io_regs = sp->io_map;
>>
>> -       ret = psp_check_sev_support(psp);
>> +       /* Read the feature register to get the PSP capability */
>> +       capability = ioread32(psp->io_regs + psp->vdata->feature_reg);
>> +
>> +       ret = psp_check_support(psp, capability);
>>         if (ret)
>>                 goto e_disable;
>>
>> @@ -101,7 +153,7 @@ int psp_dev_init(struct sp_device *sp)
>>                 goto e_err;
>>         }
>>
>> -       ret = sev_dev_init(psp);
>> +       ret = psp_init(psp, capability);
>>         if (ret)
>>                 goto e_irq;
>>
>> @@ -139,6 +191,8 @@ void psp_dev_destroy(struct sp_device *sp)
>>
>>         sev_dev_destroy(psp);
>>
>> +       tee_dev_destroy(psp);
>> +
>>         sp_free_psp_irq(sp, psp);
>>  }
>>
>> @@ -154,6 +208,18 @@ void psp_clear_sev_irq_handler(struct psp_device *psp)
>>         psp_set_sev_irq_handler(psp, NULL, NULL);
>>  }
>>
>> +void psp_set_tee_irq_handler(struct psp_device *psp, psp_irq_handler_t handler,
>> +                            void *data)
>> +{
>> +       psp->tee_irq_data = data;
>> +       psp->tee_irq_handler = handler;
>> +}
>> +
>> +void psp_clear_tee_irq_handler(struct psp_device *psp)
>> +{
>> +       psp_set_tee_irq_handler(psp, NULL, NULL);
>> +}
>> +
>>  struct psp_device *psp_get_master_device(void)
>>  {
>>         struct sp_device *sp = sp_get_psp_master_device();
>> diff --git a/drivers/crypto/ccp/psp-dev.h b/drivers/crypto/ccp/psp-dev.h
>> index 7c014ac..ef38e41 100644
>> --- a/drivers/crypto/ccp/psp-dev.h
>> +++ b/drivers/crypto/ccp/psp-dev.h
>> @@ -40,13 +40,21 @@ struct psp_device {
>>         psp_irq_handler_t sev_irq_handler;
>>         void *sev_irq_data;
>>
>> +       psp_irq_handler_t tee_irq_handler;
>> +       void *tee_irq_data;
>> +
>>         void *sev_data;
>> +       void *tee_data;
>>  };
>>
>>  void psp_set_sev_irq_handler(struct psp_device *psp, psp_irq_handler_t handler,
>>                              void *data);
>>  void psp_clear_sev_irq_handler(struct psp_device *psp);
>>
>> +void psp_set_tee_irq_handler(struct psp_device *psp, psp_irq_handler_t handler,
>> +                            void *data);
>> +void psp_clear_tee_irq_handler(struct psp_device *psp);
>> +
>>  struct psp_device *psp_get_master_device(void);
>>
>>  #endif /* __PSP_DEV_H */
>> diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h
>> index 0394c75..4235946 100644
>> --- a/drivers/crypto/ccp/sp-dev.h
>> +++ b/drivers/crypto/ccp/sp-dev.h
>> @@ -2,7 +2,7 @@
>>  /*
>>   * AMD Secure Processor driver
>>   *
>> - * Copyright (C) 2017-2018 Advanced Micro Devices, Inc.
>> + * Copyright (C) 2017-2019 Advanced Micro Devices, Inc.
>>   *
>>   * Author: Tom Lendacky <thomas.lendacky@xxxxxxx>
>>   * Author: Gary R Hook <gary.hook@xxxxxxx>
>> @@ -45,8 +45,17 @@ struct sev_vdata {
>>         const unsigned int cmdbuff_addr_hi_reg;
>>  };
>>
>> +struct tee_vdata {
>> +       const unsigned int cmdresp_reg;
>> +       const unsigned int cmdbuff_addr_lo_reg;
>> +       const unsigned int cmdbuff_addr_hi_reg;
>> +       const unsigned int ring_wptr_reg;
>> +       const unsigned int ring_rptr_reg;
>> +};
>> +
>>  struct psp_vdata {
>>         const struct sev_vdata *sev;
>> +       const struct tee_vdata *tee;
>>         const unsigned int feature_reg;
>>         const unsigned int inten_reg;
>>         const unsigned int intsts_reg;
>> diff --git a/drivers/crypto/ccp/sp-pci.c b/drivers/crypto/ccp/sp-pci.c
>> index 733693d..56c1f61 100644
>> --- a/drivers/crypto/ccp/sp-pci.c
>> +++ b/drivers/crypto/ccp/sp-pci.c
>> @@ -2,7 +2,7 @@
>>  /*
>>   * AMD Secure Processor device driver
>>   *
>> - * Copyright (C) 2013,2018 Advanced Micro Devices, Inc.
>> + * Copyright (C) 2013,2019 Advanced Micro Devices, Inc.
>>   *
>>   * Author: Tom Lendacky <thomas.lendacky@xxxxxxx>
>>   * Author: Gary R Hook <gary.hook@xxxxxxx>
>> @@ -274,6 +274,14 @@ static int sp_pci_resume(struct pci_dev *pdev)
>>         .cmdbuff_addr_hi_reg    = 0x109e4,
>>  };
>>
>> +static const struct tee_vdata teev1 = {
>> +       .cmdresp_reg            = 0x10544,
>> +       .cmdbuff_addr_lo_reg    = 0x10548,
>> +       .cmdbuff_addr_hi_reg    = 0x1054c,
>> +       .ring_wptr_reg          = 0x10550,
>> +       .ring_rptr_reg          = 0x10554,
>> +};
>> +
>>  static const struct psp_vdata pspv1 = {
>>         .sev                    = &sevv1,
>>         .feature_reg            = 0x105fc,
>> @@ -287,6 +295,13 @@ static int sp_pci_resume(struct pci_dev *pdev)
>>         .inten_reg              = 0x10690,
>>         .intsts_reg             = 0x10694,
>>  };
>> +
>> +static const struct psp_vdata pspv3 = {
>> +       .tee                    = &teev1,
>> +       .feature_reg            = 0x109fc,
>> +       .inten_reg              = 0x10690,
>> +       .intsts_reg             = 0x10694,
>> +};
>>  #endif
>>
>>  static const struct sp_dev_vdata dev_vdata[] = {
>> @@ -320,12 +335,22 @@ static int sp_pci_resume(struct pci_dev *pdev)
>>                 .psp_vdata = &pspv2,
>>  #endif
>>         },
>> +       {       /* 4 */
>> +               .bar = 2,
>> +#ifdef CONFIG_CRYPTO_DEV_SP_CCP
>> +               .ccp_vdata = &ccpv5a,
>> +#endif
>> +#ifdef CONFIG_CRYPTO_DEV_SP_PSP
>> +               .psp_vdata = &pspv3,
>> +#endif
>> +       },
>>  };
>>  static const struct pci_device_id sp_pci_table[] = {
>>         { PCI_VDEVICE(AMD, 0x1537), (kernel_ulong_t)&dev_vdata[0] },
>>         { PCI_VDEVICE(AMD, 0x1456), (kernel_ulong_t)&dev_vdata[1] },
>>         { PCI_VDEVICE(AMD, 0x1468), (kernel_ulong_t)&dev_vdata[2] },
>>         { PCI_VDEVICE(AMD, 0x1486), (kernel_ulong_t)&dev_vdata[3] },
>> +       { PCI_VDEVICE(AMD, 0x15DF), (kernel_ulong_t)&dev_vdata[4] },
>>         /* Last entry must be zero */
>>         { 0, }
>>  };
>> diff --git a/drivers/crypto/ccp/tee-dev.c b/drivers/crypto/ccp/tee-dev.c
>> new file mode 100644
>> index 0000000..b2b0215
>> --- /dev/null
>> +++ b/drivers/crypto/ccp/tee-dev.c
>> @@ -0,0 +1,237 @@
>> +// SPDX-License-Identifier: MIT
>> +/*
>> + * AMD Trusted Execution Environment (TEE) interface
>> + *
>> + * Author: Rijo Thomas <Rijo-john.Thomas@xxxxxxx>
>> + *
>> + * 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, &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);
>> +}
>> diff --git a/drivers/crypto/ccp/tee-dev.h b/drivers/crypto/ccp/tee-dev.h
>> new file mode 100644
>> index 0000000..0d51a0a7
>> --- /dev/null
>> +++ b/drivers/crypto/ccp/tee-dev.h
>> @@ -0,0 +1,108 @@
>> +/* SPDX-License-Identifier: MIT */
>> +/*
>> + * Copyright 2019 Advanced Micro Devices, Inc.
>> + *
>> + * Author: Rijo Thomas <Rijo-john.Thomas@xxxxxxx>
>> + *
>> + */
>> +
>> +/* This file describes the TEE communication interface between host and AMD
>> + * Secure Processor
>> + */
>> +
>> +#ifndef __TEE_DEV_H__
>> +#define __TEE_DEV_H__
>> +
>> +#include <linux/device.h>
>> +#include <linux/mutex.h>
>> +
>> +#define TEE_DEFAULT_TIMEOUT            10
>> +#define MAX_BUFFER_SIZE                        992
>> +
>> +/**
>> + * enum tee_ring_cmd_id - TEE interface commands for ring buffer configuration
>> + * @TEE_RING_INIT_CMD:         Initialize ring buffer
>> + * @TEE_RING_DESTROY_CMD:      Destroy ring buffer
>> + * @TEE_RING_MAX_CMD:          Maximum command id
>> + */
>> +enum tee_ring_cmd_id {
>> +       TEE_RING_INIT_CMD               = 0x00010000,
>> +       TEE_RING_DESTROY_CMD            = 0x00020000,
>> +       TEE_RING_MAX_CMD                = 0x000F0000,
>> +};
>> +
>> +/**
>> + * struct tee_init_ring_cmd - Command to init TEE ring buffer
>> + * @low_addr:  bits [31:0] of the physical address of ring buffer
>> + * @hi_addr:   bits [63:32] of the physical address of ring buffer
>> + * @size:      size of ring buffer in bytes
>> + */
>> +struct tee_init_ring_cmd {
>> +       u32 low_addr;
>> +       u32 hi_addr;
>> +       u32 size;
>> +};
>> +
>> +#define MAX_RING_BUFFER_ENTRIES                32
>> +
>> +/**
>> + * struct ring_buf_manager - Helper structure to manage ring buffer.
>> + * @ring_start:  starting address of ring buffer
>> + * @ring_size:   size of ring buffer in bytes
>> + * @ring_pa:     physical address of ring buffer
>> + * @wptr:        index to the last written entry in ring buffer
>> + */
>> +struct ring_buf_manager {
>> +       void *ring_start;
>> +       u32 ring_size;
>> +       phys_addr_t ring_pa;
>> +       u32 wptr;
>> +};
>> +
>> +struct psp_tee_device {
>> +       struct device *dev;
>> +       struct psp_device *psp;
>> +       void __iomem *io_regs;
>> +       struct tee_vdata *vdata;
>> +       struct ring_buf_manager rb_mgr;
>> +};
>> +
>> +/**
>> + * enum tee_cmd_state - TEE command states for the ring buffer interface
>> + * @TEE_CMD_STATE_INIT:      initial state of command when sent from host
>> + * @TEE_CMD_STATE_PROCESS:   command being processed by TEE environment
>> + * @TEE_CMD_STATE_COMPLETED: command processing completed
>> + */
>> +enum tee_cmd_state {
>> +       TEE_CMD_STATE_INIT,
>> +       TEE_CMD_STATE_PROCESS,
>> +       TEE_CMD_STATE_COMPLETED,
>> +};
>> +
>> +/**
>> + * struct tee_ring_cmd - Structure of the command buffer in TEE ring
>> + * @cmd_id:      refers to &enum tee_cmd_id. Command id for the ring buffer
>> + *               interface
>> + * @cmd_state:   refers to &enum tee_cmd_state
>> + * @status:      status of TEE command execution
>> + * @res0:        reserved region
>> + * @pdata:       private data (currently unused)
>> + * @res1:        reserved region
>> + * @buf:         TEE command specific buffer
>> + */
>> +struct tee_ring_cmd {
>> +       u32 cmd_id;
>> +       u32 cmd_state;
>> +       u32 status;
>> +       u32 res0[1];
>> +       u64 pdata;
>> +       u32 res1[2];
>> +       u8 buf[MAX_BUFFER_SIZE];
>> +
>> +       /* Total size: 1024 bytes */
>> +} __packed;
>> +
>> +int tee_dev_init(struct psp_device *psp);
>> +void tee_dev_destroy(struct psp_device *psp);
>> +
>> +#endif /* __TEE_DEV_H__ */
>> --
>> 1.9.1
>>