tpm: Keep CLKRUN enabled throughout the duration of transmit_cmd()

Commit 5e572cab92f0bb5 ("tpm: Enable CLKRUN protocol for Braswell
systems") disabled CLKRUN protocol during TPM transactions and re-enabled
once the transaction is completed. But there were still some corner cases
observed where, reading of TPM header failed for savestate command
while going to suspend, which resulted in suspend failure.
To fix this issue keep the CLKRUN protocol disabled for the entire
duration of a single TPM command and not disabling and re-enabling
again for every TPM transaction. For the other TPM accesses outside
TPM command flow, add a higher level of disabling and re-enabling
the CLKRUN protocol, instead of doing for every TPM transaction.

Fixes: 5e572cab92f0bb5 ("tpm: Enable CLKRUN protocol for Braswell systems")
Signed-off-by: Azhar Shaikh <azhar.shaikh@intel.com>
Reviewed-by: Jarkko Sakkinen  <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen  <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen  <jarkko.sakkinen@linux.intel.com>

1 files changed, 98 insertions, 10 deletions

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index aff567840e50..3238731fdbfd 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -37,6 +37,8 @@
  */
 #define TPM_POLL_SLEEP	1  /* msec */
 
+static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value);
+
 static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
 					bool check_cancel, bool *canceled)
 {
@@ -487,19 +489,28 @@ static bool tpm_tis_update_timeouts(struct tpm_chip *chip,
 	int i, rc;
 	u32 did_vid;
 
+	if (chip->ops->clk_enable != NULL)
+		chip->ops->clk_enable(chip, true);
+
 	rc = tpm_tis_read32(priv, TPM_DID_VID(0), &did_vid);
 	if (rc < 0)
-		return rc;
+		goto out;
 
 	for (i = 0; i != ARRAY_SIZE(vendor_timeout_overrides); i++) {
 		if (vendor_timeout_overrides[i].did_vid != did_vid)
 			continue;
 		memcpy(timeout_cap, vendor_timeout_overrides[i].timeout_us,
 		       sizeof(vendor_timeout_overrides[i].timeout_us));
-		return true;
+		rc = true;
 	}
 
-	return false;
+	rc = false;
+
+out:
+	if (chip->ops->clk_enable != NULL)
+		chip->ops->clk_enable(chip, false);
+
+	return rc;
 }
 
 /*
@@ -719,14 +730,74 @@ void tpm_tis_remove(struct tpm_chip *chip)
 	u32 interrupt;
 	int rc;
 
+	tpm_tis_clkrun_enable(chip, true);
+
 	rc = tpm_tis_read32(priv, reg, &interrupt);
 	if (rc < 0)
 		interrupt = 0;
 
 	tpm_tis_write32(priv, reg, ~TPM_GLOBAL_INT_ENABLE & interrupt);
+
+	tpm_tis_clkrun_enable(chip, false);
+
+	if (priv->ilb_base_addr)
+		iounmap(priv->ilb_base_addr);
 }
 EXPORT_SYMBOL_GPL(tpm_tis_remove);
 
+/**
+ * tpm_tis_clkrun_enable() - Keep clkrun protocol disabled for entire duration
+ *                           of a single TPM command
+ * @chip:	TPM chip to use
+ * @value:	1 - Disable CLKRUN protocol, so that clocks are free running
+ *		0 - Enable CLKRUN protocol
+ * Call this function directly in tpm_tis_remove() in error or driver removal
+ * path, since the chip->ops is set to NULL in tpm_chip_unregister().
+ */
+static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value)
+{
+	struct tpm_tis_data *data = dev_get_drvdata(&chip->dev);
+	u32 clkrun_val;
+
+	if (!IS_ENABLED(CONFIG_X86) || !is_bsw())
+		return;
+
+	if (value) {
+		data->flags |= TPM_TIS_CLK_ENABLE;
+		data->clkrun_enabled++;
+		if (data->clkrun_enabled > 1)
+			return;
+		clkrun_val = ioread32(data->ilb_base_addr + LPC_CNTRL_OFFSET);
+
+		/* Disable LPC CLKRUN# */
+		clkrun_val &= ~LPC_CLKRUN_EN;
+		iowrite32(clkrun_val, data->ilb_base_addr + LPC_CNTRL_OFFSET);
+
+		/*
+		 * Write any random value on port 0x80 which is on LPC, to make
+		 * sure LPC clock is running before sending any TPM command.
+		 */
+		outb(0xCC, 0x80);
+	} else {
+		data->clkrun_enabled--;
+		if (data->clkrun_enabled)
+			return;
+
+		clkrun_val = ioread32(data->ilb_base_addr + LPC_CNTRL_OFFSET);
+
+		/* Enable LPC CLKRUN# */
+		clkrun_val |= LPC_CLKRUN_EN;
+		iowrite32(clkrun_val, data->ilb_base_addr + LPC_CNTRL_OFFSET);
+
+		/*
+		 * Write any random value on port 0x80 which is on LPC, to make
+		 * sure LPC clock is running before sending any TPM command.
+		 */
+		outb(0xCC, 0x80);
+		data->flags &= ~TPM_TIS_CLK_ENABLE;
+	}
+}
+
 static const struct tpm_class_ops tpm_tis = {
 	.flags = TPM_OPS_AUTO_STARTUP,
 	.status = tpm_tis_status,
@@ -739,6 +810,7 @@ static const struct tpm_class_ops tpm_tis = {
 	.req_canceled = tpm_tis_req_canceled,
 	.request_locality = request_locality,
 	.relinquish_locality = release_locality,
+	.clk_enable = tpm_tis_clkrun_enable,
 };
 
 int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
@@ -773,6 +845,9 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 			return -ENOMEM;
 	}
 
+	if (chip->ops->clk_enable != NULL)
+		chip->ops->clk_enable(chip, true);
+
 	if (wait_startup(chip, 0) != 0) {
 		rc = -ENODEV;
 		goto out_err;
@@ -864,14 +939,18 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 	}
 
 	rc = tpm_chip_register(chip);
-	if (rc && is_bsw())
-		iounmap(priv->ilb_base_addr);
+	if (rc)
+		goto out_err;
 
-	return rc;
+	if (chip->ops->clk_enable != NULL)
+		chip->ops->clk_enable(chip, false);
+
+	return 0;
 out_err:
+	if ((chip->ops != NULL) && (chip->ops->clk_enable != NULL))
+		chip->ops->clk_enable(chip, false);
+
 	tpm_tis_remove(chip);
-	if (is_bsw())
-		iounmap(priv->ilb_base_addr);
 
 	return rc;
 }
@@ -884,22 +963,31 @@ static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
 	u32 intmask;
 	int rc;
 
+	if (chip->ops->clk_enable != NULL)
+		chip->ops->clk_enable(chip, true);
+
 	/* reenable interrupts that device may have lost or
 	 * BIOS/firmware may have disabled
 	 */
 	rc = tpm_tis_write8(priv, TPM_INT_VECTOR(priv->locality), priv->irq);
 	if (rc < 0)
-		return;
+		goto out;
 
 	rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
 	if (rc < 0)
-		return;
+		goto out;
 
 	intmask |= TPM_INTF_CMD_READY_INT
 	    | TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_DATA_AVAIL_INT
 	    | TPM_INTF_STS_VALID_INT | TPM_GLOBAL_INT_ENABLE;
 
 	tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
+
+out:
+	if (chip->ops->clk_enable != NULL)
+		chip->ops->clk_enable(chip, false);
+
+	return;
 }
 
 int tpm_tis_resume(struct device *dev)