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: <stable@vger.kernel.org>
[PHuewe: without this fix these 'broken' Atmel TPMs won't function on
older kernels]
Signed-off-by: "Berg, Christopher" <Christopher.Berg@atmel.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>

3 files changed, 75 insertions, 21 deletions

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index bef6cceffc3a..6af17002a115 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -491,11 +491,10 @@ static int tpm_startup(struct tpm_chip *chip, __be16 startup_type)
 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;
@@ -529,25 +528,46 @@ int tpm_get_timeouts(struct tpm_chip *chip)
             != 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;
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index a9ed2270c25d..2c46734b266d 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -373,6 +373,36 @@ out_err:
         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
@@ -437,6 +467,7 @@ static const struct tpm_class_ops tpm_tis = {
         .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,
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index fff1d0976f80..8350c538b486 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -39,6 +39,9 @@ struct tpm_class_ops {
         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)