From 8274c2926fbee8125a0cba4d38cd020b98c397c8 Mon Sep 17 00:00:00 2001 From: Caveh Jalali Date: Thu, 10 Sep 2020 01:25:29 -0700 Subject: drivers/spi/tpm: Improve error checking This adds error checking in paths that previously ignored TPM communication errors. We hit this case occasionally during "Checking cr50 for pending updates"; previously we would go down this path and eventually time out using MAX_STATUS_TIMEOUT, which is 2 minutes. Now, we detect the failure and return with an error indication instead of timing out after a long time. The root cause of the communication error is an open issue. BUG=b:168090038 TEST=booted on volteer, observed error handling when "Checking cr50 for pending updates" fails. Signed-off-by: Caveh Jalali Change-Id: Ia8a1202000abce1857ee694b06b1478e6b045069 Reviewed-on: https://review.coreboot.org/c/coreboot/+/45232 Tested-by: build bot (Jenkins) Reviewed-by: Jes Klinke Reviewed-by: Tim Wawrzynczak --- src/drivers/spi/tpm/tpm.c | 56 +++++++++++++++++++++++++++++++++-------------- 1 file changed, 39 insertions(+), 17 deletions(-) (limited to 'src/drivers/spi') diff --git a/src/drivers/spi/tpm/tpm.c b/src/drivers/spi/tpm/tpm.c index 66db671b50..d65decda12 100644 --- a/src/drivers/spi/tpm/tpm.c +++ b/src/drivers/spi/tpm/tpm.c @@ -348,7 +348,7 @@ static int read_tpm_sts(uint32_t *status) return tpm2_read_reg(TPM_STS_REG, status, sizeof(*status)); } -static int write_tpm_sts(uint32_t status) +static int __must_check write_tpm_sts(uint32_t status) { return tpm2_write_reg(TPM_STS_REG, &status, sizeof(status)); } @@ -688,9 +688,9 @@ union fifo_transfer_buffer { * Transfer requested number of bytes to or from TPM FIFO, accounting for the * current burst count value. */ -static void fifo_transfer(size_t transfer_size, - union fifo_transfer_buffer buffer, - enum fifo_transfer_direction direction) +static int __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; @@ -711,18 +711,23 @@ static void fifo_transfer(size_t transfer_size, */ transaction_size = MIN(transaction_size, 64); - if (direction == fifo_receive) - tpm2_read_reg(TPM_DATA_FIFO_REG, - buffer.rx_buffer + handled_so_far, - transaction_size); - else - tpm2_write_reg(TPM_DATA_FIFO_REG, - buffer.tx_buffer + handled_so_far, - transaction_size); + if (direction == fifo_receive) { + if (!tpm2_read_reg(TPM_DATA_FIFO_REG, + buffer.rx_buffer + handled_so_far, + transaction_size)) + return 0; + } else { + if (!tpm2_write_reg(TPM_DATA_FIFO_REG, + buffer.tx_buffer + handled_so_far, + transaction_size)) + return 0; + } handled_so_far += transaction_size; } while (handled_so_far != transfer_size); + + return 1; } size_t tpm2_process_command(const void *tpm2_command, size_t command_size, @@ -755,7 +760,10 @@ size_t tpm2_process_command(const void *tpm2_command, size_t command_size, } /* Let the TPM know that the command is coming. */ - write_tpm_sts(TPM_STS_COMMAND_READY); + if (!write_tpm_sts(TPM_STS_COMMAND_READY)) { + printk(BIOS_ERR, "TPM_STS_COMMAND_READY failed\n"); + return 0; + } /* * TPM commands and responses written to and read from the FIFO @@ -769,10 +777,17 @@ size_t tpm2_process_command(const void *tpm2_command, size_t command_size, * burst count or the maximum PDU size, whatever is smaller. */ fifo_buffer.tx_buffer = cmd_body; - fifo_transfer(command_size, fifo_buffer, fifo_transmit); + if (!fifo_transfer(command_size, fifo_buffer, fifo_transmit)) { + printk(BIOS_ERR, "fifo_transfer %zd command bytes failed\n", + command_size); + return 0; + } /* Now tell the TPM it can start processing the command. */ - write_tpm_sts(TPM_STS_GO); + if (!write_tpm_sts(TPM_STS_GO)) { + 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; @@ -815,7 +830,11 @@ size_t tpm2_process_command(const void *tpm2_command, size_t command_size, */ bytes_to_go = payload_size - 1 - HEADER_SIZE; fifo_buffer.rx_buffer = rsp_body + HEADER_SIZE; - fifo_transfer(bytes_to_go, fifo_buffer, fifo_receive); + if (!fifo_transfer(bytes_to_go, fifo_buffer, fifo_receive)) { + 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); @@ -840,7 +859,10 @@ size_t tpm2_process_command(const void *tpm2_command, size_t command_size, } /* Move the TPM back to idle state. */ - write_tpm_sts(TPM_STS_COMMAND_READY); + if (!write_tpm_sts(TPM_STS_COMMAND_READY)) { + printk(BIOS_ERR, "TPM_STS_COMMAND_READY failed\n"); + return 0; + } return payload_size; } -- cgit v1.2.3