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-rw-r--r--src/soc/amd/common/block/lpc/espi_util.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/src/soc/amd/common/block/lpc/espi_util.c b/src/soc/amd/common/block/lpc/espi_util.c
index 276bb3cdc3..c5aac3814a 100644
--- a/src/soc/amd/common/block/lpc/espi_util.c
+++ b/src/soc/amd/common/block/lpc/espi_util.c
@@ -419,6 +419,7 @@ struct espi_cmd {
union espi_txhdr1 hdr1;
union espi_txhdr2 hdr2;
union espi_txdata data;
+ uint32_t expected_status_codes;
} __packed;
/* Wait up to ESPI_CMD_TIMEOUT_US for hardware to clear DNCMD_STATUS bit. */
@@ -512,13 +513,13 @@ static int espi_send_command(const struct espi_cmd *cmd)
return -1;
}
- if (status & ~ESPI_STATUS_DNCMD_COMPLETE) {
+ if (status & ~(ESPI_STATUS_DNCMD_COMPLETE | cmd->expected_status_codes)) {
espi_show_failure(cmd, "Error: unexpected eSPI status register bits set",
status);
return -1;
}
- espi_write32(ESPI_SLAVE0_INT_STS, ESPI_STATUS_DNCMD_COMPLETE);
+ espi_write32(ESPI_SLAVE0_INT_STS, status);
return 0;
}
@@ -530,6 +531,33 @@ static int espi_send_reset(void)
.cmd_type = CMD_TYPE_IN_BAND_RESET,
.cmd_sts = 1,
},
+
+ /*
+ * When performing an in-band reset the host controller and the
+ * peripheral can have mismatched IO configs.
+ *
+ * i.e., The eSPI peripheral can be in IO-4 mode while, the
+ * eSPI host will be in IO-1. This results in the peripheral
+ * getting invalid packets and thus not responding.
+ *
+ * If the peripheral is alerting when we perform an in-band
+ * reset, there is a race condition in espi_send_command.
+ * 1) espi_send_command clears the interrupt status.
+ * 2) eSPI host controller hardware notices the alert and sends
+ * a GET_STATUS.
+ * 3) espi_send_command writes the in-band reset command.
+ * 4) eSPI hardware enqueues the in-band reset until GET_STATUS
+ * is complete.
+ * 5) GET_STATUS fails with NO_RESPONSE and sets the interrupt
+ * status.
+ * 6) eSPI hardware performs in-band reset.
+ * 7) espi_send_command checks the status and sees a
+ * NO_RESPONSE bit.
+ *
+ * As a workaround we allow the NO_RESPONSE status code when
+ * we perform an in-band reset.
+ */
+ .expected_status_codes = ESPI_STATUS_NO_RESPONSE,
};
return espi_send_command(&cmd);