| /* SPDX-License-Identifier: BSD-3-Clause */ |
| /* This is a driver for a SPI interfaced TPM2 device. |
| * |
| * It assumes that the required SPI interface has been initialized before the |
| * driver is started. A 'sruct spi_slave' pointer passed at initialization is |
| * used to direct traffic to the correct SPI interface. This driver does not |
| * provide a way to instantiate multiple TPM devices. Also, to keep things |
| * simple, the driver unconditionally uses of TPM locality zero. |
| * |
| * References to documentation are based on the TCG issued "TPM Profile (PTP) |
| * Specification Revision 00.43". |
| */ |
| |
| #include <assert.h> |
| #include <commonlib/endian.h> |
| #include <console/console.h> |
| #include <delay.h> |
| #include <drivers/tpm/cr50.h> |
| #include <endian.h> |
| #include <security/tpm/tis.h> |
| #include <string.h> |
| #include <timer.h> |
| #include <types.h> |
| |
| #include "tpm.h" |
| |
| /* Assorted TPM2 registers for interface type FIFO. */ |
| #define TPM_ACCESS_REG (TPM_LOCALITY_0_SPI_BASE + 0) |
| #define TPM_STS_REG (TPM_LOCALITY_0_SPI_BASE + 0x18) |
| #define TPM_DATA_FIFO_REG (TPM_LOCALITY_0_SPI_BASE + 0x24) |
| #define TPM_INTF_ID_REG (TPM_LOCALITY_0_SPI_BASE + 0x30) |
| #define TPM_DID_VID_REG (TPM_LOCALITY_0_SPI_BASE + 0xf00) |
| #define TPM_RID_REG (TPM_LOCALITY_0_SPI_BASE + 0xf04) |
| #define TPM_FW_VER (TPM_LOCALITY_0_SPI_BASE + 0xf90) |
| #define CR50_BOARD_CFG (TPM_LOCALITY_0_SPI_BASE + 0xfe0) |
| |
| #define CR50_TIMEOUT_INIT_MS 30000 /* Very long timeout for TPM init */ |
| |
| /* SPI slave structure for TPM device. */ |
| static struct spi_slave spi_slave; |
| |
| /* Cached TPM device identification. */ |
| static struct tpm2_info tpm_info; |
| |
| /* |
| * TODO(vbendeb): make CONFIG(DEBUG_TPM) an int to allow different level of |
| * debug traces. Right now it is either 0 or 1. |
| */ |
| static const int debug_level_ = CONFIG(DEBUG_TPM); |
| |
| /* |
| * SPI frame header for TPM transactions is 4 bytes in size, it is described |
| * in section "6.4.6 Spi Bit Protocol". |
| */ |
| typedef struct { |
| unsigned char body[4]; |
| } spi_frame_header; |
| |
| void tpm2_get_info(struct tpm2_info *info) |
| { |
| *info = tpm_info; |
| } |
| |
| /* |
| * Each TPM2 SPI transaction starts the same: CS is asserted, the 4 byte |
| * header is sent to the TPM, the master waits til TPM is ready to continue. |
| */ |
| static enum cb_err start_transaction(int read_write, size_t bytes, unsigned int addr) |
| { |
| spi_frame_header header, header_resp; |
| uint8_t byte; |
| int i; |
| int ret; |
| struct stopwatch sw; |
| static int tpm_sync_needed; |
| static struct stopwatch wake_up_sw; |
| |
| if (CONFIG(TPM_GOOGLE)) { |
| /* |
| * First Cr50 access in each coreboot stage where TPM is used will be |
| * prepended by a wake up pulse on the CS line. |
| */ |
| int wakeup_needed = 1; |
| |
| /* Wait for TPM to finish previous transaction if needed */ |
| if (tpm_sync_needed) { |
| if (cr50_wait_tpm_ready() != CB_SUCCESS) |
| printk(BIOS_ERR, "Timeout waiting for TPM IRQ!\n"); |
| |
| /* |
| * During the first invocation of this function on each stage |
| * this if () clause code does not run (as tpm_sync_needed |
| * value is zero), during all following invocations the |
| * stopwatch below is guaranteed to be started. |
| */ |
| if (!stopwatch_expired(&wake_up_sw)) |
| wakeup_needed = 0; |
| } else { |
| tpm_sync_needed = 1; |
| } |
| |
| if (wakeup_needed) { |
| /* Just in case Cr50 is asleep. */ |
| spi_claim_bus(&spi_slave); |
| udelay(1); |
| spi_release_bus(&spi_slave); |
| udelay(100); |
| } |
| |
| /* |
| * The Cr50 on H1 does not go to sleep for 1 second after any |
| * SPI slave activity, let's be conservative and limit the |
| * window to 900 ms. |
| */ |
| stopwatch_init_msecs_expire(&wake_up_sw, 900); |
| } |
| |
| /* |
| * The first byte of the frame header encodes the transaction type |
| * (read or write) and transfer size (set to length - 1), limited to |
| * 64 bytes. |
| */ |
| header.body[0] = (read_write ? 0x80 : 0) | 0x40 | (bytes - 1); |
| |
| /* The rest of the frame header is the TPM register address. */ |
| for (i = 0; i < 3; i++) |
| header.body[i + 1] = (addr >> (8 * (2 - i))) & 0xff; |
| |
| /* CS assert wakes up the slave. */ |
| spi_claim_bus(&spi_slave); |
| |
| /* |
| * The TCG TPM over SPI specification introduces the notion of SPI |
| * flow control (Section "6.4.5 Flow Control"). |
| * |
| * Again, the slave (TPM device) expects each transaction to start |
| * with a 4 byte header trasmitted by master. The header indicates if |
| * the master needs to read or write a register, and the register |
| * address. |
| * |
| * If the slave needs to stall the transaction (for instance it is not |
| * ready to send the register value to the master), it sets the MOSI |
| * line to 0 during the last clock of the 4 byte header. In this case |
| * the master is supposed to start polling the SPI bus, one byte at |
| * time, until the last bit in the received byte (transferred during |
| * the last clock of the byte) is set to 1. |
| * |
| * Due to some SPI controllers' shortcomings (Rockchip comes to |
| * mind...) we transmit the 4 byte header without checking the byte |
| * transmitted by the TPM during the transaction's last byte. |
| * |
| * We know that cr50 is guaranteed to set the flow control bit to 0 |
| * during the header transfer. Real TPM2 are fast enough to not require |
| * to stall the master. They might still use this feature, so test the |
| * last bit after shifting in the address bytes. |
| * crosbug.com/p/52132 has been opened to track this. |
| */ |
| |
| header_resp.body[3] = 0; |
| if (CONFIG(TPM_GOOGLE)) |
| ret = spi_xfer(&spi_slave, header.body, sizeof(header.body), NULL, 0); |
| else |
| ret = spi_xfer(&spi_slave, header.body, sizeof(header.body), |
| header_resp.body, sizeof(header_resp.body)); |
| if (ret) { |
| printk(BIOS_ERR, "SPI-TPM: transfer error\n"); |
| spi_release_bus(&spi_slave); |
| return CB_ERR; |
| } |
| |
| if (header_resp.body[3] & 1) |
| return CB_SUCCESS; |
| |
| /* |
| * Now poll the bus until TPM removes the stall bit. Give it up to 100 |
| * ms to sort it out - it could be saving stuff in nvram at some point. |
| */ |
| stopwatch_init_msecs_expire(&sw, 100); |
| do { |
| if (stopwatch_expired(&sw)) { |
| printk(BIOS_ERR, "TPM flow control failure\n"); |
| spi_release_bus(&spi_slave); |
| return CB_ERR; |
| } |
| spi_xfer(&spi_slave, NULL, 0, &byte, 1); |
| } while (!(byte & 1)); |
| |
| return CB_SUCCESS; |
| } |
| |
| /* |
| * Print out the contents of a buffer, if debug is enabled. Skip registers |
| * other than FIFO, unless debug_level_ is 2. |
| */ |
| static void trace_dump(const char *prefix, uint32_t reg, |
| size_t bytes, const uint8_t *buffer, |
| int force) |
| { |
| static char prev_prefix; |
| static unsigned int prev_reg; |
| static int current_char; |
| const int BYTES_PER_LINE = 32; |
| |
| if (!force) { |
| if (!debug_level_) |
| return; |
| |
| if ((debug_level_ < 2) && (reg != TPM_DATA_FIFO_REG)) |
| return; |
| } |
| |
| /* |
| * Do not print register address again if the last dump print was for |
| * that register. |
| */ |
| if (prev_prefix != *prefix || (prev_reg != reg)) { |
| prev_prefix = *prefix; |
| prev_reg = reg; |
| printk(BIOS_DEBUG, "\n%s %2.2x:", prefix, reg); |
| current_char = 0; |
| } |
| |
| if ((reg != TPM_DATA_FIFO_REG) && (bytes == 4)) { |
| /* |
| * This must be a regular register address, print the 32 bit |
| * value. |
| */ |
| printk(BIOS_DEBUG, " %8.8x", *(const uint32_t *)buffer); |
| } else { |
| int i; |
| |
| /* |
| * Data read from or written to FIFO or not in 4 byte |
| * quantiites is printed byte at a time. |
| */ |
| for (i = 0; i < bytes; i++) { |
| if (current_char && |
| !(current_char % BYTES_PER_LINE)) { |
| printk(BIOS_DEBUG, "\n "); |
| current_char = 0; |
| } |
| (current_char)++; |
| printk(BIOS_DEBUG, " %2.2x", buffer[i]); |
| } |
| } |
| } |
| |
| /* |
| * Once transaction is initiated and the TPM indicated that it is ready to go, |
| * write the actual bytes to the register. |
| */ |
| static void write_bytes(const void *buffer, size_t bytes) |
| { |
| spi_xfer(&spi_slave, buffer, bytes, NULL, 0); |
| } |
| |
| /* |
| * Once transaction is initiated and the TPM indicated that it is ready to go, |
| * read the actual bytes from the register. |
| */ |
| static void read_bytes(void *buffer, size_t bytes) |
| { |
| spi_xfer(&spi_slave, NULL, 0, buffer, bytes); |
| } |
| |
| /* |
| * To write a register, start transaction, transfer data to the TPM, deassert |
| * CS when done. |
| */ |
| static enum cb_err tpm2_write_reg(unsigned int reg_number, const void *buffer, size_t bytes) |
| { |
| trace_dump("W", reg_number, bytes, buffer, 0); |
| if (start_transaction(false, bytes, reg_number) != CB_SUCCESS) |
| return CB_ERR; |
| write_bytes(buffer, bytes); |
| spi_release_bus(&spi_slave); |
| return CB_SUCCESS; |
| } |
| |
| /* |
| * To read a register, start transaction, transfer data from the TPM, deassert |
| * CS when done. |
| * |
| * In case of failure zero out the user buffer. |
| */ |
| static enum cb_err tpm2_read_reg(unsigned int reg_number, void *buffer, size_t bytes) |
| { |
| if (start_transaction(true, bytes, reg_number) != CB_SUCCESS) { |
| memset(buffer, 0, bytes); |
| return CB_ERR; |
| } |
| read_bytes(buffer, bytes); |
| spi_release_bus(&spi_slave); |
| trace_dump("R", reg_number, bytes, buffer, 0); |
| return CB_SUCCESS; |
| } |
| |
| /* |
| * Status register is accessed often, wrap reading and writing it into |
| * dedicated functions. |
| */ |
| static enum cb_err read_tpm_sts(uint32_t *status) |
| { |
| return tpm2_read_reg(TPM_STS_REG, status, sizeof(*status)); |
| } |
| |
| static enum cb_err __must_check write_tpm_sts(uint32_t status) |
| { |
| return tpm2_write_reg(TPM_STS_REG, &status, sizeof(status)); |
| } |
| |
| /* |
| * The TPM may limit the transaction bytes count (burst count) below the 64 |
| * bytes max. The current value is available as a field of the status |
| * register. |
| */ |
| static uint32_t get_burst_count(void) |
| { |
| uint32_t status; |
| |
| read_tpm_sts(&status); |
| return (status & TPM_STS_BURST_COUNT_MASK) >> TPM_STS_BURST_COUNT_SHIFT; |
| } |
| |
| static uint8_t tpm2_read_access_reg(void) |
| { |
| uint8_t access; |
| tpm2_read_reg(TPM_ACCESS_REG, &access, sizeof(access)); |
| /* We do not care about access establishment bit state. Ignore it. */ |
| return access & ~TPM_ACCESS_ESTABLISHMENT; |
| } |
| |
| static void tpm2_write_access_reg(uint8_t cmd) |
| { |
| /* Writes to access register can set only 1 bit at a time. */ |
| assert(!(cmd & (cmd - 1))); |
| |
| tpm2_write_reg(TPM_ACCESS_REG, &cmd, sizeof(cmd)); |
| } |
| |
| static enum cb_err tpm2_claim_locality(void) |
| { |
| uint8_t access; |
| struct stopwatch sw; |
| |
| /* |
| * Locality is released by TPM reset. |
| * |
| * If locality is taken at this point, this could be due to the fact |
| * that the TPM is performing a long operation and has not processed |
| * reset request yet. We'll wait up to CR50_TIMEOUT_INIT_MS and see if |
| * it releases locality when reset is processed. |
| */ |
| stopwatch_init_msecs_expire(&sw, CR50_TIMEOUT_INIT_MS); |
| do { |
| access = tpm2_read_access_reg(); |
| if (access & TPM_ACCESS_ACTIVE_LOCALITY) { |
| /* |
| * Don't bombard the chip with traffic, let it keep |
| * processing the command. |
| */ |
| mdelay(2); |
| continue; |
| } |
| |
| /* |
| * Ok, the locality is free, TPM must be reset, let's claim |
| * it. |
| */ |
| |
| tpm2_write_access_reg(TPM_ACCESS_REQUEST_USE); |
| access = tpm2_read_access_reg(); |
| if (access != (TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY)) { |
| break; |
| } |
| |
| printk(BIOS_INFO, "TPM ready after %lld ms\n", |
| stopwatch_duration_msecs(&sw)); |
| |
| return CB_SUCCESS; |
| } while (!stopwatch_expired(&sw)); |
| |
| printk(BIOS_ERR, |
| "Failed to claim locality 0 after %lld ms, status: %#x\n", |
| stopwatch_duration_msecs(&sw), access); |
| |
| return CB_ERR; |
| } |
| |
| /* Device/vendor ID values of the TPM devices this driver supports. */ |
| static const uint32_t supported_did_vids[] = { |
| 0x00281ae0, /* H1 based Cr50 security chip. */ |
| 0x504a6666, /* H1D3C based Ti50 security chip. */ |
| 0x0000104a /* ST33HTPH2E32 */ |
| }; |
| |
| int tpm2_init(struct spi_slave *spi_if) |
| { |
| uint32_t did_vid, status, intf_id; |
| uint8_t cmd; |
| int retries; |
| |
| memcpy(&spi_slave, spi_if, sizeof(*spi_if)); |
| |
| /* Clear any pending IRQs. */ |
| if (CONFIG(TPM_GOOGLE)) |
| cr50_plat_irq_status(); |
| |
| /* |
| * 150 ms should be enough to synchronize with the TPM even under the |
| * worst nested reset request conditions. In vast majority of cases |
| * there would be no wait at all. |
| */ |
| printk(BIOS_INFO, "Probing TPM: "); |
| for (retries = 15; retries > 0; retries--) { |
| int i; |
| |
| /* In case of failure to read div_vid is set to zero. */ |
| tpm2_read_reg(TPM_DID_VID_REG, &did_vid, sizeof(did_vid)); |
| |
| for (i = 0; i < ARRAY_SIZE(supported_did_vids); i++) |
| if (did_vid == supported_did_vids[i]) |
| break; /* TPM is up and ready. */ |
| |
| if (i < ARRAY_SIZE(supported_did_vids)) |
| break; |
| |
| /* TPM might be resetting, let's retry in a bit. */ |
| mdelay(10); |
| printk(BIOS_INFO, "."); |
| } |
| |
| if (!retries) { |
| printk(BIOS_ERR, "\n%s: Failed to connect to the TPM\n", |
| __func__); |
| return -1; |
| } |
| |
| printk(BIOS_INFO, " done!\n"); |
| |
| /* Google TPMs haven't always been 100% accurate in reflecting the spec (particularly |
| * on older versions) and are always TPM 2.0. */ |
| if (!CONFIG(TPM_GOOGLE)) { |
| if (tpm2_read_reg(TPM_INTF_ID_REG, &intf_id, sizeof(intf_id)) != CB_SUCCESS) { |
| printk(BIOS_ERR, "\n%s: Failed to read interface ID register\n", |
| __func__); |
| return -1; |
| } |
| if ((be32toh(intf_id) & 0xF) == 0xF) { |
| printk(BIOS_DEBUG, "\n%s: Not a TPM2 device\n", __func__); |
| return -1; |
| } |
| } |
| |
| // FIXME: Move this to tpm_setup() |
| if (tpm_first_access_this_boot()) |
| /* |
| * Claim locality 0, do it only during the first |
| * initialization after reset. |
| */ |
| if (tpm2_claim_locality() != CB_SUCCESS) |
| return -1; |
| |
| if (read_tpm_sts(&status) != CB_SUCCESS) { |
| printk(BIOS_ERR, "Reading status reg failed\n"); |
| return -1; |
| } |
| if ((status & TPM_STS_FAMILY_MASK) != TPM_STS_FAMILY_TPM_2_0) { |
| printk(BIOS_ERR, "unexpected TPM family value, status: %#x\n", |
| status); |
| return -1; |
| } |
| |
| /* |
| * Locality claimed, read the revision value and set up the tpm_info |
| * structure. |
| */ |
| tpm2_read_reg(TPM_RID_REG, &cmd, sizeof(cmd)); |
| tpm_info.vendor_id = did_vid & 0xffff; |
| tpm_info.device_id = did_vid >> 16; |
| tpm_info.revision = cmd; |
| |
| printk(BIOS_INFO, "Connected to device vid:did:rid of %4.4x:%4.4x:%2.2x\n", |
| tpm_info.vendor_id, tpm_info.device_id, tpm_info.revision); |
| |
| /* Do some GSC-specific things here. */ |
| if (CONFIG(TPM_GOOGLE)) { |
| if (tpm_first_access_this_boot()) { |
| /* This is called for the side-effect of printing the firmware version |
| string */ |
| cr50_get_firmware_version(NULL); |
| cr50_set_board_cfg(); |
| } |
| } |
| return 0; |
| } |
| |
| /* |
| * This is in seconds, certain TPM commands, like key generation, can take |
| * long time to complete. |
| */ |
| #define MAX_STATUS_TIMEOUT 120 |
| static enum cb_err wait_for_status(uint32_t status_mask, uint32_t status_expected) |
| { |
| uint32_t status; |
| struct stopwatch sw; |
| |
| stopwatch_init_usecs_expire(&sw, MAX_STATUS_TIMEOUT * 1000 * 1000); |
| do { |
| udelay(1000); |
| if (stopwatch_expired(&sw)) { |
| printk(BIOS_ERR, "failed to get expected status %#x\n", |
| status_expected); |
| return CB_ERR; |
| } |
| read_tpm_sts(&status); |
| } while ((status & status_mask) != status_expected); |
| |
| return CB_SUCCESS; |
| } |
| |
| enum fifo_transfer_direction { |
| fifo_transmit = 0, |
| fifo_receive = 1 |
| }; |
| |
| /* Union allows to avoid casting away 'const' on transmit buffers. */ |
| union fifo_transfer_buffer { |
| uint8_t *rx_buffer; |
| const uint8_t *tx_buffer; |
| }; |
| |
| /* |
| * Transfer requested number of bytes to or from TPM FIFO, accounting for the |
| * current burst count value. |
| */ |
| static enum cb_err __must_check fifo_transfer(size_t transfer_size, |
| union fifo_transfer_buffer buffer, |
| enum fifo_transfer_direction direction) |
| { |
| size_t transaction_size; |
| size_t burst_count; |
| size_t handled_so_far = 0; |
| |
| do { |
| do { |
| /* Could be zero when TPM is busy. */ |
| burst_count = get_burst_count(); |
| } while (!burst_count); |
| |
| transaction_size = transfer_size - handled_so_far; |
| transaction_size = MIN(transaction_size, burst_count); |
| |
| /* |
| * The SPI frame header does not allow to pass more than 64 |
| * bytes. |
| */ |
| transaction_size = MIN(transaction_size, 64); |
| |
| if (direction == fifo_receive) { |
| if (tpm2_read_reg(TPM_DATA_FIFO_REG, |
| buffer.rx_buffer + handled_so_far, |
| transaction_size) != CB_SUCCESS) |
| return CB_ERR; |
| } else { |
| if (tpm2_write_reg(TPM_DATA_FIFO_REG, |
| buffer.tx_buffer + handled_so_far, |
| transaction_size) != CB_SUCCESS) |
| return CB_ERR; |
| } |
| |
| handled_so_far += transaction_size; |
| |
| } while (handled_so_far != transfer_size); |
| |
| return CB_SUCCESS; |
| } |
| |
| size_t tpm2_process_command(const void *tpm2_command, size_t command_size, |
| void *tpm2_response, size_t max_response) |
| { |
| uint32_t status; |
| uint32_t expected_status_bits; |
| size_t payload_size; |
| size_t bytes_to_go; |
| const uint8_t *cmd_body = tpm2_command; |
| uint8_t *rsp_body = tpm2_response; |
| union fifo_transfer_buffer fifo_buffer; |
| const int HEADER_SIZE = 6; |
| |
| /* Do not try using an uninitialized TPM. */ |
| if (!tpm_info.vendor_id) |
| return 0; |
| |
| /* Skip the two byte tag, read the size field. */ |
| payload_size = read_be32(cmd_body + 2); |
| |
| /* Sanity check. */ |
| if (payload_size != command_size) { |
| printk(BIOS_ERR, |
| "Command size mismatch: encoded %zd != requested %zd\n", |
| payload_size, command_size); |
| trace_dump("W", TPM_DATA_FIFO_REG, command_size, cmd_body, 1); |
| printk(BIOS_DEBUG, "\n"); |
| return 0; |
| } |
| |
| /* Let the TPM know that the command is coming. */ |
| if (write_tpm_sts(TPM_STS_COMMAND_READY) != CB_SUCCESS) { |
| printk(BIOS_ERR, "TPM_STS_COMMAND_READY failed\n"); |
| return 0; |
| } |
| |
| /* |
| * TPM commands and responses written to and read from the FIFO |
| * register (0x24) are datagrams of variable size, prepended by a 6 |
| * byte header. |
| * |
| * The specification description of the state machine is a bit vague, |
| * but from experience it looks like there is no need to wait for the |
| * sts.expect bit to be set, at least with the 9670 and cr50 devices. |
| * Just write the command into FIFO, making sure not to exceed the |
| * burst count or the maximum PDU size, whatever is smaller. |
| */ |
| fifo_buffer.tx_buffer = cmd_body; |
| if (fifo_transfer(command_size, fifo_buffer, fifo_transmit) != CB_SUCCESS) { |
| printk(BIOS_ERR, "fifo_transfer %zd command bytes failed\n", |
| command_size); |
| return 0; |
| } |
| |
| /* Now tell the TPM it can start processing the command. */ |
| if (write_tpm_sts(TPM_STS_GO) != CB_SUCCESS) { |
| printk(BIOS_ERR, "TPM_STS_GO failed\n"); |
| return 0; |
| } |
| |
| /* Now wait for it to report that the response is ready. */ |
| expected_status_bits = TPM_STS_VALID | TPM_STS_DATA_AVAIL; |
| if (wait_for_status(expected_status_bits, expected_status_bits) != CB_SUCCESS) { |
| /* |
| * If timed out, which should never happen, let's at least |
| * print out the offending command. |
| */ |
| trace_dump("W", TPM_DATA_FIFO_REG, command_size, cmd_body, 1); |
| printk(BIOS_DEBUG, "\n"); |
| return 0; |
| } |
| |
| /* |
| * The response is ready, let's read it. First we read the FIFO |
| * payload header, to see how much data to expect. The response header |
| * size is fixed to six bytes, the total payload size is stored in |
| * network order in the last four bytes. |
| */ |
| tpm2_read_reg(TPM_DATA_FIFO_REG, rsp_body, HEADER_SIZE); |
| |
| /* Find out the total payload size, skipping the two byte tag. */ |
| payload_size = read_be32(rsp_body + 2); |
| |
| if (payload_size > max_response) { |
| /* |
| * TODO(vbendeb): at least drain the FIFO here or somehow let |
| * the TPM know that the response can be dropped. |
| */ |
| printk(BIOS_ERR, " TPM response too long (%zd bytes)", |
| payload_size); |
| return 0; |
| } |
| |
| /* |
| * Now let's read all but the last byte in the FIFO to make sure the |
| * status register is showing correct flow control bits: 'more data' |
| * until the last byte and then 'no more data' once the last byte is |
| * read. |
| */ |
| bytes_to_go = payload_size - 1 - HEADER_SIZE; |
| fifo_buffer.rx_buffer = rsp_body + HEADER_SIZE; |
| if (fifo_transfer(bytes_to_go, fifo_buffer, fifo_receive) != CB_SUCCESS) { |
| printk(BIOS_ERR, "fifo_transfer %zd receive bytes failed\n", |
| bytes_to_go); |
| return 0; |
| } |
| |
| /* Verify that there is still data to read. */ |
| read_tpm_sts(&status); |
| if ((status & expected_status_bits) != expected_status_bits) { |
| printk(BIOS_ERR, "unexpected intermediate status %#x\n", |
| status); |
| return 0; |
| } |
| |
| /* Read the last byte of the PDU. */ |
| tpm2_read_reg(TPM_DATA_FIFO_REG, rsp_body + payload_size - 1, 1); |
| |
| /* Terminate the dump, if enabled. */ |
| if (debug_level_) |
| printk(BIOS_DEBUG, "\n"); |
| |
| /* Verify that 'data available' is not asseretd any more. */ |
| read_tpm_sts(&status); |
| if ((status & expected_status_bits) != TPM_STS_VALID) { |
| printk(BIOS_ERR, "unexpected final status %#x\n", status); |
| return 0; |
| } |
| |
| /* Move the TPM back to idle state. */ |
| if (write_tpm_sts(TPM_STS_COMMAND_READY) != CB_SUCCESS) { |
| printk(BIOS_ERR, "TPM_STS_COMMAND_READY failed\n"); |
| return 0; |
| } |
| |
| return payload_size; |
| } |
| |
| enum cb_err tis_vendor_write(unsigned int addr, const void *buffer, size_t bytes) |
| { |
| return tpm2_write_reg(addr, buffer, bytes); |
| } |
| |
| enum cb_err tis_vendor_read(unsigned int addr, void *buffer, size_t bytes) |
| { |
| return tpm2_read_reg(addr, buffer, bytes); |
| } |