tpm: Provide a generic means to override the chip returned timeouts

Some Atmel TPMs provide completely wrong timeouts from their
TPM_CAP_PROP_TIS_TIMEOUT query. This patch detects that and returns
new correct values via a DID/VID table in the TIS driver.

Tested on ARM using an AT97SC3204T FW version 37.16

Cc: <[e-mail]>
[PHuewe: without this fix these 'broken' Atmel TPMs won't function on
older kernels]
Signed-off-by: "Berg, Christopher" <[e-mail]>
Signed-off-by: Jason Gunthorpe <[e-mail]>

Signed-off-by: Peter Huewe <[e-mail]>

drivers/char/tpm/tpm-interface.c

···
 int tpm_get_timeouts(struct tpm_chip *chip)
 {
 	struct tpm_cmd_t tpm_cmd;
-	struct timeout_t *timeout_cap;
+	unsigned long new_timeout[4];
+	unsigned long old_timeout[4];
 	struct duration_t *duration_cap;
 	ssize_t rc;
-	u32 timeout;
-	unsigned int scale = 1;
 
 	tpm_cmd.header.in = tpm_getcap_header;
 	tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
···
 	    != sizeof(tpm_cmd.header.out) + sizeof(u32) + 4 * sizeof(u32))
 		return -EINVAL;
 
-	timeout_cap = &tpm_cmd.params.getcap_out.cap.timeout;
-	/* Don't overwrite default if value is 0 */
-	timeout = be32_to_cpu(timeout_cap->a);
-	if (timeout && timeout < 1000) {
-		/* timeouts in msec rather usec */
-		scale = 1000;
-		chip->vendor.timeout_adjusted = true;
+	old_timeout[0] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.a);
+	old_timeout[1] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.b);
+	old_timeout[2] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.c);
+	old_timeout[3] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.d);
+	memcpy(new_timeout, old_timeout, sizeof(new_timeout));
+
+	/*
+	 * Provide ability for vendor overrides of timeout values in case
+	 * of misreporting.
+	 */
+	if (chip->ops->update_timeouts != NULL)
+		chip->vendor.timeout_adjusted =
+			chip->ops->update_timeouts(chip, new_timeout);
+
+	if (!chip->vendor.timeout_adjusted) {
+		/* Don't overwrite default if value is 0 */
+		if (new_timeout[0] != 0 && new_timeout[0] < 1000) {
+			int i;
+
+			/* timeouts in msec rather usec */
+			for (i = 0; i != ARRAY_SIZE(new_timeout); i++)
+				new_timeout[i] *= 1000;
+			chip->vendor.timeout_adjusted = true;
+		}
 	}
-	if (timeout)
-		chip->vendor.timeout_a = usecs_to_jiffies(timeout * scale);
-	timeout = be32_to_cpu(timeout_cap->b);
-	if (timeout)
-		chip->vendor.timeout_b = usecs_to_jiffies(timeout * scale);
-	timeout = be32_to_cpu(timeout_cap->c);
-	if (timeout)
-		chip->vendor.timeout_c = usecs_to_jiffies(timeout * scale);
-	timeout = be32_to_cpu(timeout_cap->d);
-	if (timeout)
-		chip->vendor.timeout_d = usecs_to_jiffies(timeout * scale);
+
+	/* Report adjusted timeouts */
+	if (chip->vendor.timeout_adjusted) {
+		dev_info(chip->dev,
+			 HW_ERR "Adjusting reported timeouts: A %lu->%luus B %lu->%luus C %lu->%luus D %lu->%luus\n",
+			 old_timeout[0], new_timeout[0],
+			 old_timeout[1], new_timeout[1],
+			 old_timeout[2], new_timeout[2],
+			 old_timeout[3], new_timeout[3]);
+	}
+
+	chip->vendor.timeout_a = usecs_to_jiffies(new_timeout[0]);
+	chip->vendor.timeout_b = usecs_to_jiffies(new_timeout[1]);
+	chip->vendor.timeout_c = usecs_to_jiffies(new_timeout[2]);
+	chip->vendor.timeout_d = usecs_to_jiffies(new_timeout[3]);
 
 duration:
 	tpm_cmd.header.in = tpm_getcap_header;

drivers/char/tpm/tpm_tis.c

···
 	return rc;
 }
 
+struct tis_vendor_timeout_override {
+	u32 did_vid;
+	unsigned long timeout_us[4];
+};
+
+static const struct tis_vendor_timeout_override vendor_timeout_overrides[] = {
+	/* Atmel 3204 */
+	{ 0x32041114, { (TIS_SHORT_TIMEOUT*1000), (TIS_LONG_TIMEOUT*1000),
+			(TIS_SHORT_TIMEOUT*1000), (TIS_SHORT_TIMEOUT*1000) } },
+};
+
+static bool tpm_tis_update_timeouts(struct tpm_chip *chip,
+				    unsigned long *timeout_cap)
+{
+	int i;
+	u32 did_vid;
+
+	did_vid = ioread32(chip->vendor.iobase + TPM_DID_VID(0));
+
+	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;
+	}
+
+	return false;
+}
+
 /*
  * Early probing for iTPM with STS_DATA_EXPECT flaw.
  * Try sending command without itpm flag set and if that
···
 	.recv = tpm_tis_recv,
 	.send = tpm_tis_send,
 	.cancel = tpm_tis_ready,
+	.update_timeouts = tpm_tis_update_timeouts,
 	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 	.req_canceled = tpm_tis_req_canceled,

include/linux/tpm.h

···
 	int (*send) (struct tpm_chip *chip, u8 *buf, size_t len);
 	void (*cancel) (struct tpm_chip *chip);
 	u8 (*status) (struct tpm_chip *chip);
+	bool (*update_timeouts)(struct tpm_chip *chip,
+				unsigned long *timeout_cap);
+
 };
 
 #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)