V4L/DVB (6647): xc2028: retry firmware load if tuner does not respond

In practice, the tuner occasionally fails to respond correctly after a
firmware load.  Retry the firmware load if the firmware/hardware version
we read back from the tuner after programming does not match what we
expect.

Signed-off-by: Chris Pascoe <c.pascoe@itee.uq.edu.au>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 34 insertions, 3 deletions

diff --git a/drivers/media/video/tuner-xc2028.c b/drivers/media/video/tuner-xc2028.c
index 8140d8ad0792..cc6fa2fa859b 100644
--- a/drivers/media/video/tuner-xc2028.c
+++ b/drivers/media/video/tuner-xc2028.c
@@ -75,6 +75,9 @@ struct xc2028_data {
         int                     firm_size;
         __u16                   firm_version;
 
+        __u16                   hwmodel;
+        __u16                   hwvers;
+
         struct xc2028_ctrl      ctrl;
 
         struct firmware_properties cur_fw;
@@ -607,7 +610,7 @@ static int check_firmware(struct dvb_frontend *fe, enum tuner_mode new_mode,
                           v4l2_std_id std, fe_bandwidth_t bandwidth)
 {
         struct xc2028_data      *priv = fe->tuner_priv;
-        int                     rc = 0;
+        int                     rc = 0, is_retry = 0;
         unsigned int            type = 0;
         struct firmware_properties new_fw;
         u16                     version, hwmodel;
@@ -654,6 +657,7 @@ static int check_firmware(struct dvb_frontend *fe, enum tuner_mode new_mode,
                 };
         }
 
+retry:
         new_fw.type = type;
         new_fw.id = std;
         new_fw.std_req = std;
@@ -739,14 +743,34 @@ skip_std_specific:
                         &new_fw.id, new_fw.scode_nr);
 
 check_device:
-        xc2028_get_reg(priv, 0x0004, &version);
-        xc2028_get_reg(priv, 0x0008, &hwmodel);
+        if (xc2028_get_reg(priv, 0x0004, &version) < 0 ||
+            xc2028_get_reg(priv, 0x0008, &hwmodel) < 0) {
+                tuner_err("Unable to read tuner registers.\n");
+                goto fail;
+        }
 
         tuner_info("Device is Xceive %d version %d.%d, "
                    "firmware version %d.%d\n",
                    hwmodel, (version & 0xf000) >> 12, (version & 0xf00) >> 8,
                    (version & 0xf0) >> 4, version & 0xf);
 
+        /* Check firmware version against what we downloaded. */
+        if (priv->firm_version != ((version & 0xf0) << 4 | (version & 0x0f))) {
+                tuner_err("Incorrect readback of firmware version.\n");
+                goto fail;
+        }
+
+        /* Check that the tuner hardware model remains consistent over time. */
+        if (priv->hwmodel == 0 && (hwmodel == 2028 || hwmodel == 3028)) {
+                priv->hwmodel = hwmodel;
+                priv->hwvers  = version & 0xff00;
+        } else if (priv->hwmodel == 0 || priv->hwmodel != hwmodel ||
+                   priv->hwvers != (version & 0xff00)) {
+                tuner_err("Read invalid device hardware information - tuner "
+                          "hung?\n");
+                goto fail;
+        }
+
         memcpy(&priv->cur_fw, &new_fw, sizeof(priv->cur_fw));
 
         /*
@@ -761,6 +785,13 @@ check_device:
 
 fail:
         memset(&priv->cur_fw, 0, sizeof(priv->cur_fw));
+        if (!is_retry) {
+                msleep(50);
+                is_retry = 1;
+                tuner_dbg("Retrying firmware load\n");
+                goto retry;
+        }
+
         if (rc == -ENOENT)
                 rc = -EINVAL;
         return rc;