Hi
I am using an isp1763 on MPC8360 and linux-3.0.0-2 from debian.
The driver is ported from Sebastian's original isp1760 and I am forward porting to Arvid's version.
I noticed that a custom timing delay is missing on the new isp1760. This delay is added in [1]
and an mmiowb() is added in [2]
In my port to the isp1763, not having this delay makes usb mass storage detection unstable.
Adding the code back improves things, but I am still having some timing issues.
Here is the patch for the missing delay...
<diff>
diff --git a/drivers/usb/host/isp1760-hcd.c b/drivers/usb/host/isp1760-hcd.c
index 125e261..b07879c 100644
--- a/drivers/usb/host/isp1760-hcd.c
+++ b/drivers/usb/host/isp1760-hcd.c
@@ -1103,6 +1103,17 @@ static void handle_done_ptds(struct usb_hcd *hcd)
int modified;
int skip_map;
+ /*
+ * When this function is called from the interrupt handler to enqueue
+ * a follow-up packet, the SKIP register gets written and read back
+ * almost immediately. With ISP1761, this register requires a delay of
+ * 195ns between a write and subsequent read (see section 15.1.1.3).
+ * memory barrier is used to ensure the delay is counted after the write
+ * is finished on the device.
+ */
+ mmiowb();
+ ndelay(195);
+
skip_map = reg_read32(hcd->regs, HC_INT_PTD_SKIPMAP_REG);
priv->int_done_map &= ~skip_map;
skip_map = reg_read32(hcd->regs, HC_ATL_PTD_SKIPMAP_REG);
</diff>
The symptoms I am experiencing is very similar to this case [3]
where only some usb mass storage device works and others do not.
My debugging seems to lead to ptd_error like this:
nxp-isp1763 f8010000.usb: check_atl_transfer: ptd error:
dw0: a80000f8 dw1: 00002021 dw2: 0001a000 dw3: 56000000
dw4: 00000000 dw5: 00000000 dw6: 00000000 dw7: 00000000
usb 1-1.2: reset high speed USB device number 4 using nxp-isp1763
sd 2:0:0:0: [sdb] No Caching mode page present
sd 2:0:0:0: [sdb] Assuming drive cache: write through
nxp-isp1763 f8010000.usb: check_atl_transfer: ptd error:
dw0: 28008000 dw1: 00002420 dw2: 00038000 dw3: 52000000
dw4: 00000000 dw5: 00000000 dw6: 00000000 dw7: 00000000
usb 1-1.2: reset high speed USB device number 4 using nxp-isp1763
Q1: Is my understanding correct (that we need to re-add the ndelay(195) to not violate timing?)
Q2: Any ideas on how I should proceed further in debugging?
References:
[1] http://kerneltrap.org/mailarchive/linux-usb/2009/3/25/5238724
[2] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/patch/drivers/usb/host/isp1760-hcd.c?id=ebb8a4e48722c8f5e04a6490b197d2fbc894a0f6
[3] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/patch/drivers/usb/host/isp1760-hcd.c?id=0954e1c258c4018bfd370da41fbb5deb34582976
Thanks for everyone's time.
--
Richard Retanubun
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