98 lines
3.2 KiB
Diff
98 lines
3.2 KiB
Diff
From e82060f0cf390ba8e4f79a54e68cef9a38088104 Mon Sep 17 00:00:00 2001
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From: Nayna Jain <nayna@linux.vnet.ibm.com>
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Date: Fri, 10 Nov 2017 17:16:35 -0500
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Subject: [PATCH] tpm: ignore burstcount to improve tpm_tis send() performance
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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The TPM burstcount status indicates the number of bytes that can
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be sent to the TPM without causing bus wait states. Effectively,
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it is the number of empty bytes in the command FIFO.
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This patch optimizes the tpm_tis_send_data() function by checking
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the burstcount only once. And if the burstcount is valid, it writes
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all the bytes at once, permitting wait state.
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After this change, performance on a TPM 1.2 with an 8 byte
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burstcount for 1000 extends improved from ~41sec to ~14sec.
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Suggested-by: Ken Goldman <kgold@linux.vnet.ibm.com> in
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conjunction with the TPM Device Driver work group.
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Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
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Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
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Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
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Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
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Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
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---
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tpm_tis_core.c | 42 +++++++++++++++---------------------------
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1 file changed, 15 insertions(+), 27 deletions(-)
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diff --git a/tpm_tis_core.c b/tpm_tis_core.c
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index a338701..a6b4149 100644
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--- a/tpm_tis_core.c
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+++ b/tpm_tis_core.c
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@@ -256,7 +256,6 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
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{
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struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
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int rc, status, burstcnt;
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- size_t count = 0;
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bool itpm = priv->flags & TPM_TIS_ITPM_WORKAROUND;
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status = tpm_tis_status(chip);
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@@ -270,36 +269,25 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
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}
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}
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- while (count < len - 1) {
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- burstcnt = get_burstcount(chip);
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- if (burstcnt < 0) {
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- dev_err(&chip->dev, "Unable to read burstcount\n");
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- rc = burstcnt;
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- goto out_err;
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- }
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- burstcnt = min_t(int, burstcnt, len - count - 1);
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- rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality),
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- burstcnt, buf + count);
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- if (rc < 0)
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- goto out_err;
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- count += burstcnt;
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-
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- if (__wait_for_tpm_stat(chip, TPM_STS_VALID,
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- chip->timeout_c, 1,
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- &priv->int_queue, false) < 0) {
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- rc = -ETIME;
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- goto out_err;
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- }
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- status = tpm_tis_status(chip);
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- if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) {
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- rc = -EIO;
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- goto out_err;
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- }
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+ /*
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+ * Get the initial burstcount to ensure TPM is ready to
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+ * accept data, even when waiting for burstcount is disabled.
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+ */
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+ burstcnt = get_burstcount(chip);
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+ if (burstcnt < 0) {
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+ dev_err(&chip->dev, "Unable to read burstcount\n");
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+ rc = burstcnt;
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+ goto out_err;
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}
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+ rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality),
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+ len -1, buf);
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+ if (rc < 0)
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+ goto out_err;
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+
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/* write last byte */
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- rc = tpm_tis_write8(priv, TPM_DATA_FIFO(priv->locality), buf[count]);
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+ rc = tpm_tis_write8(priv, TPM_DATA_FIFO(priv->locality), buf[len-1]);
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if (rc < 0)
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goto out_err;
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--
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1.8.3.1
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