scsi: make probe more error resilient

* Some usb devices do not like report-luns, assume it as single lun device
  and move further.
* Make inquiry of the device first for 36bytes and then determine what
  is the additional size to read.

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>

3 files changed, 36 insertions, 13 deletions

diff --git a/slof/fs/scsi-disk.fs b/slof/fs/scsi-disk.fs
index 1d1539f..1978471 100644
--- a/slof/fs/scsi-disk.fs
+++ b/slof/fs/scsi-disk.fs
@@ -90,19 +90,23 @@ CREATE cdb 10 allot
     dup 0<> IF " read-blocks" dump-scsi-error -65 throw ELSE drop THEN
 ;
 
-: inquiry ( -- buffer | NULL )
-    scsi-disk-debug? IF
-        ." SCSI-DISK: inquiry " .s cr
-    THEN
-    \ WARNING: ATAPI devices with libata seem to ignore the MSB of
-    \ the allocation length... let's only ask for ff bytes
-    ff cdb scsi-build-inquiry
+: (inquiry) ( size -- buffer | NULL )
+    dup cdb scsi-build-inquiry
     \ 16 retries for inquiry to flush out any UAs
-    scratch ff scsi-dir-read cdb scsi-param-size 10 retry-scsi-command
+    scratch swap scsi-dir-read cdb scsi-param-size 10 retry-scsi-command
     \ Success ?
     0= IF scratch ELSE 2drop 0 THEN
 ;
 
+: inquiry ( -- buffer | NULL )
+    scsi-disk-debug? IF
+	." SCSI-DISK: inquiry " .s cr
+    THEN
+    d# 36 (inquiry) 0= IF 0 EXIT THEN
+    scratch inquiry-data>add-length c@ 5 +
+    (inquiry)
+;
+
 : read-capacity ( -- blocksize #blocks )
     \ Now issue the read-capacity command
     scsi-disk-debug? IF
diff --git a/slof/fs/scsi-host-helpers.fs b/slof/fs/scsi-host-helpers.fs
index 9ff3613..579ce37 100644
--- a/slof/fs/scsi-host-helpers.fs
+++ b/slof/fs/scsi-host-helpers.fs
@@ -92,16 +92,21 @@
 CREATE sector d# 512 allot
 CREATE cdb 10 allot
 
-: inquiry ( -- buffer | NULL )
-    \ WARNING: ATAPI devices with libata seem to ignore the MSB of
-    \ the allocation length... let's only ask for ff bytes
-    ff cdb scsi-build-inquiry
+: (inquiry) ( size -- buffer | NULL )
+    dup cdb scsi-build-inquiry
     \ 16 retries for inquiry to flush out any UAs
-    sector ff scsi-dir-read cdb scsi-param-size 10 retry-scsi-command
+    sector swap scsi-dir-read cdb scsi-param-size 10 retry-scsi-command
     \ Success ?
     0= IF sector ELSE 2drop 0 THEN
 ;
 
+\ Read the initial 36bytes and then decide how much more is to be read
+: inquiry ( -- buffer | NULL )
+    d# 36 (inquiry) 0= IF 0 EXIT THEN
+    sector inquiry-data>add-length c@ 5 +
+    (inquiry)
+;
+
 : report-luns ( -- [ sector ] true | false )
     200 cdb scsi-build-report-luns
     \ 16 retries to flush out any UAs
diff --git a/slof/fs/scsi-probe-helpers.fs b/slof/fs/scsi-probe-helpers.fs
index 7cb40c2..307838f 100644
--- a/slof/fs/scsi-probe-helpers.fs
+++ b/slof/fs/scsi-probe-helpers.fs
@@ -37,6 +37,20 @@
 	    rot                           ( devarray ndev mem devcur )
 	    dup >r x! r> 8 +              ( devarray ndev devcur )
 	    swap 1 +
+	ELSE
+	    dev-max-target 1 = IF
+		\ Some USB MSC devices do not implement report
+		\ luns. That will stall the bulk pipe. These devices are
+		\ single lun devices, report it accordingly
+
+		( devarray devcur ndev )
+		16 alloc-mem ( devarray devcur ndev mem )
+		dup 16 0 fill ( devarray devcur ndev mem )
+		dup 0 0 dev-generate-srplun swap x!  ( devarray devcur ndev mem )
+		rot x!  ( devarray ndev )
+		1 +
+		UNLOOP EXIT
+	    THEN
 	THEN
     LOOP
     nip