src/soc/amd/common/block/psp/psp_smi.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <amdblocks/psp.h>
   4 #include <amdblocks/smi.h>
   5 #include <console/console.h>
   6 #include <cpu/x86/cache.h>
   7 #include <device/mmio.h>
   8 #include <types.h>
   9 #include "psp_def.h"
  10 #include "psp_smi_flash.h"
  11
  12 /* PSP to x86 commands */
  13 #define MBOX_PSP_CMD_SPI_INFO           0x83
  14 #define MBOX_PSP_CMD_SPI_READ           0x84
  15 #define MBOX_PSP_CMD_SPI_WRITE          0x85
  16 #define MBOX_PSP_CMD_SPI_ERASE          0x86
  17 #define MBOX_PSP_CMD_SPI_RPMC_INC_MC    0x88
  18 #define MBOX_PSP_CMD_SPI_RPMC_REQ_MC    0x89
  19
  20 extern struct {
  21         uint8_t buffer[P2C_BUFFER_MAXSIZE];
  22 }  __aligned(32) p2c_buffer;
  23
  24 static const uintptr_t p2c_mbox_base = (uintptr_t)&p2c_buffer.buffer;
  25
  26 #define P2C_MBOX_COMMAND_OFFSET         0x00
  27 #define P2C_MBOX_STATUS_OFFSET          0x04
  28 #define P2C_MBOX_BUFFER_OFFSET          0x08
  29
  30 union p2c_mbox_status {
  31         struct {
  32                 uint32_t checksum       :  8; /* [ 0.. 7] */
  33                 uint32_t checksum_en    :  1; /* [ 8.. 8] */
  34                 uint32_t reserved       : 22; /* [ 9..30] */
  35                 uint32_t command_ready  :  1; /* [31..31] */
  36         } __packed fields;
  37         uint32_t raw;
  38 };
  39
  40 static uint8_t rd_bios_mbox_checksum(void)
  41 {
  42         union p2c_mbox_status status;
  43
  44         status.raw = read32p(p2c_mbox_base + P2C_MBOX_STATUS_OFFSET);
  45         return status.fields.checksum;
  46 }
  47
  48 static void wr_bios_mbox_checksum(uint8_t checksum)
  49 {
  50         union p2c_mbox_status status;
  51
  52         status.raw = read32p(p2c_mbox_base + P2C_MBOX_STATUS_OFFSET);
  53         status.fields.checksum = checksum;
  54         write32p(p2c_mbox_base + P2C_MBOX_STATUS_OFFSET, status.raw);
  55 }
  56
  57 static bool rd_bios_mbox_checksum_en(void)
  58 {
  59         union p2c_mbox_status status;
  60
  61         status.raw = read32p(p2c_mbox_base + P2C_MBOX_STATUS_OFFSET);
  62         return !!status.fields.checksum_en;
  63 }
  64
  65 static void wr_bios_mbox_ready(bool ready)
  66 {
  67         union p2c_mbox_status status;
  68
  69         status.raw = read32p(p2c_mbox_base + P2C_MBOX_STATUS_OFFSET);
  70         status.fields.command_ready = ready;
  71         write32p(p2c_mbox_base + P2C_MBOX_STATUS_OFFSET, status.raw);
  72 }
  73
  74 void enable_psp_smi(void)
  75 {
  76         wr_bios_mbox_ready(true);
  77 }
  78
  79 static void disable_psp_smi(void)
  80 {
  81         wr_bios_mbox_ready(false);
  82 }
  83
  84 static void clear_psp_command(void)
  85 {
  86         write32p(p2c_mbox_base + P2C_MBOX_COMMAND_OFFSET, 0);
  87 }
  88
  89 static uint32_t get_psp_command(void)
  90 {
  91         return read32p(p2c_mbox_base + P2C_MBOX_COMMAND_OFFSET);
  92 }
  93
  94 static struct mbox_default_buffer *get_psp_command_buffer(void)
  95 {
  96         return (struct mbox_default_buffer *)(p2c_mbox_base + P2C_MBOX_BUFFER_OFFSET);
  97 }
  98
  99 static uint32_t get_psp_cmd_buffer_length(void)
 100 {
 101         return read32(&get_psp_command_buffer()->header.size);
 102 }
 103
 104 static uint8_t calc_psp_buffer_checksum8(void)
 105 {
 106         const uint8_t *data = (const uint8_t *)get_psp_command_buffer();
 107         const size_t size = get_psp_cmd_buffer_length();
 108         uint8_t checksum = 0;
 109         size_t i;
 110
 111         for (i = 0; i < size; i++)
 112                 checksum += read8(data + i);
 113
 114         return checksum;
 115 }
 116
 117 static void write_psp_cmd_buffer_status(enum mbox_p2c_status status)
 118 {
 119         return write32(&get_psp_command_buffer()->header.status, status);
 120 }
 121
 122 static enum mbox_p2c_status check_psp_command(void)
 123 {
 124         if (rd_bios_mbox_checksum_en() &&
 125             calc_psp_buffer_checksum8() != rd_bios_mbox_checksum())
 126                 return MBOX_PSP_CRC_ERROR;
 127
 128         if (get_psp_cmd_buffer_length() > P2C_BUFFER_MAXSIZE - P2C_MBOX_BUFFER_OFFSET)
 129                 return MBOX_PSP_INVALID_PARAMETER;
 130
 131         return MBOX_PSP_SUCCESS;
 132 }
 133
 134 static void handle_psp_command(void)
 135 {
 136         enum mbox_p2c_status status;
 137         uint32_t cmd;
 138         struct mbox_default_buffer *const buffer = get_psp_command_buffer();
 139
 140         status = check_psp_command();
 141         if (status != MBOX_PSP_SUCCESS)
 142                 goto out;
 143
 144         cmd = get_psp_command();
 145
 146         switch (cmd) {
 147         case MBOX_PSP_CMD_SPI_INFO:
 148                 status = psp_smi_spi_get_info(buffer);
 149                 break;
 150         case MBOX_PSP_CMD_SPI_READ:
 151                 status = psp_smi_spi_read(buffer);
 152                 break;
 153         case MBOX_PSP_CMD_SPI_WRITE:
 154                 status = psp_smi_spi_write(buffer);
 155                 break;
 156         case MBOX_PSP_CMD_SPI_ERASE:
 157                 status = psp_smi_spi_erase(buffer);
 158                 break;
 159         case MBOX_PSP_CMD_SPI_RPMC_INC_MC:
 160                 status = psp_smi_spi_rpmc_inc_mc(buffer);
 161                 break;
 162         case MBOX_PSP_CMD_SPI_RPMC_REQ_MC:
 163                 status = psp_smi_spi_rpmc_req_mc(buffer);
 164                 break;
 165         default:
 166                 printk(BIOS_ERR, "PSP: Unknown command %d\n", cmd);
 167                 status = MBOX_PSP_UNSUPPORTED;
 168                 break;
 169         }
 170
 171 out:
 172         write_psp_cmd_buffer_status(status);
 173
 174         if (status == MBOX_PSP_SUCCESS && rd_bios_mbox_checksum_en())
 175                 wr_bios_mbox_checksum(calc_psp_buffer_checksum8());
 176
 177         if (status != MBOX_PSP_SUCCESS)
 178                 printk(BIOS_ERR, "PSP: SMI processing error. staus code %#x\n", status);
 179 }
 180
 181 /* TODO: check if all wbinvd() calls are necessary */
 182 void psp_smi_handler(void)
 183 {
 184         disable_psp_smi();
 185
 186         wbinvd();
 187
 188         handle_psp_command();
 189
 190         wbinvd();
 191
 192         clear_psp_command();
 193         enable_psp_smi();
 194
 195         wbinvd();
 196
 197         reset_psp_smi();
 198 }