This patch fixes a microcode lockup in my CD-ROM adapters when a blank
CD is inserted. However, do not try to burn CDs yet! I'm pretty sure
that trying it will end in coasters.
- Fix a few cases where we were unable to resynchronize with replies
for previous commands. The main thing is to keep reading replies
in case of a stall. This is done with the new state CLRRS.
- Since I am forgetting the basic state machine already, document it.
- Move counter increments in the looping path in its own function.
- Fix a harmless buglet in case CSW read fails to submit: do not
override state.
- Implement the Alan Stern's idea for adaptive signature checking.
Signed-off-by: Pete Zaitcev <[email protected]>
diff -urp -X dontdiff linux-2.6.12/drivers/block/ub.c linux-2.6.12-lem/drivers/block/ub.c
--- linux-2.6.12/drivers/block/ub.c 2005-06-21 12:58:18.000000000 -0700
+++ linux-2.6.12-lem/drivers/block/ub.c 2005-07-14 21:25:03.000000000 -0700
@@ -23,6 +23,7 @@
* -- Exterminate P3 printks
* -- Resove XXX's
* -- Redo "benh's retries", perhaps have spin-up code to handle them. V:D=?
+ * -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
*/
#include <linux/kernel.h>
#include <linux/module.h>
@@ -38,6 +39,73 @@
#define UB_MAJOR 180
/*
+ * The command state machine is the key model for understanding of this driver.
+ *
+ * The general rule is that all transitions are done towards the bottom
+ * of the diagram, thus preventing any loops.
+ *
+ * An exception to that is how the STAT state is handled. A counter allows it
+ * to be re-entered along the path marked with [C].
+ *
+ * +--------+
+ * ! INIT !
+ * +--------+
+ * !
+ * ub_scsi_cmd_start fails ->--------------------------------------\
+ * ! !
+ * V !
+ * +--------+ !
+ * ! CMD ! !
+ * +--------+ !
+ * ! +--------+ !
+ * was -EPIPE -->-------------------------------->! CLEAR ! !
+ * ! +--------+ !
+ * ! ! !
+ * was error -->------------------------------------- ! --------->\
+ * ! ! !
+ * /--<-- cmd->dir == NONE ? ! !
+ * ! ! ! !
+ * ! V ! !
+ * ! +--------+ ! !
+ * ! ! DATA ! ! !
+ * ! +--------+ ! !
+ * ! ! +---------+ ! !
+ * ! was -EPIPE -->--------------->! CLR2STS ! ! !
+ * ! ! +---------+ ! !
+ * ! ! ! ! !
+ * ! ! was error -->---- ! --------->\
+ * ! was error -->--------------------- ! ------------- ! --------->\
+ * ! ! ! ! !
+ * ! V ! ! !
+ * \--->+--------+ ! ! !
+ * ! STAT !<--------------------------/ ! !
+ * /--->+--------+ ! !
+ * ! ! ! !
+ * [C] was -EPIPE -->-----------\ ! !
+ * ! ! ! ! !
+ * +<---- len == 0 ! ! !
+ * ! ! ! ! !
+ * ! was error -->--------------------------------------!---------->\
+ * ! ! ! ! !
+ * +<---- bad CSW ! ! !
+ * +<---- bad tag ! ! !
+ * ! ! V ! !
+ * ! ! +--------+ ! !
+ * ! ! ! CLRRS ! ! !
+ * ! ! +--------+ ! !
+ * ! ! ! ! !
+ * \------- ! --------------------[C]--------\ ! !
+ * ! ! ! !
+ * cmd->error---\ +--------+ ! !
+ * ! +--------------->! SENSE !<----------/ !
+ * STAT_FAIL----/ +--------+ !
+ * ! ! V
+ * ! V +--------+
+ * \--------------------------------\--------------------->! DONE !
+ * +--------+
+ */
+
+/*
* Definitions which have to be scattered once we understand the layout better.
*/
@@ -91,8 +159,6 @@ struct bulk_cs_wrap {
#define US_BULK_CS_WRAP_LEN 13
#define US_BULK_CS_SIGN 0x53425355 /* spells out 'USBS' */
-/* This is for Olympus Camedia digital cameras */
-#define US_BULK_CS_OLYMPUS_SIGN 0x55425355 /* spells out 'USBU' */
#define US_BULK_STAT_OK 0
#define US_BULK_STAT_FAIL 1
#define US_BULK_STAT_PHASE 2
@@ -135,6 +201,7 @@ enum ub_scsi_cmd_state {
UB_CMDST_CLR2STS, /* Clearing before requesting status */
UB_CMDST_STAT, /* Status phase */
UB_CMDST_CLEAR, /* Clearing a stall (halt, actually) */
+ UB_CMDST_CLRRS, /* Clearing before retrying status */
UB_CMDST_SENSE, /* Sending Request Sense */
UB_CMDST_DONE /* Final state */
};
@@ -146,6 +213,7 @@ static char *ub_scsi_cmd_stname[] = {
"c2s",
"sts",
"clr",
+ "crs",
"Sen",
"fin"
};
@@ -316,6 +384,7 @@ struct ub_dev {
struct urb work_urb;
struct timer_list work_timer;
int last_pipe; /* What might need clearing */
+ __le32 signature; /* Learned signature */
struct bulk_cb_wrap work_bcb;
struct bulk_cs_wrap work_bcs;
struct usb_ctrlrequest work_cr;
@@ -339,8 +408,9 @@ static void ub_scsi_action(unsigned long
static void ub_scsi_dispatch(struct ub_dev *sc);
static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
-static void __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
+static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
+static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
int stalled_pipe);
@@ -1085,6 +1155,28 @@ static void ub_scsi_urb_compl(struct ub_
ub_state_stat(sc, cmd);
+ } else if (cmd->state == UB_CMDST_CLRRS) {
+ if (urb->status == -EPIPE) {
+ /*
+ * STALL while clearning STALL.
+ * The control pipe clears itself - nothing to do.
+ * XXX Might try to reset the device here and retry.
+ */
+ printk(KERN_NOTICE "%s: stall on control pipe\n",
+ sc->name);
+ goto Bad_End;
+ }
+
+ /*
+ * We ignore the result for the halt clear.
+ */
+
+ /* reset the endpoint toggle */
+ usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
+ usb_pipeout(sc->last_pipe), 0);
+
+ ub_state_stat_counted(sc, cmd);
+
} else if (cmd->state == UB_CMDST_CMD) {
if (urb->status == -EPIPE) {
rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
@@ -1190,52 +1282,57 @@ static void ub_scsi_urb_compl(struct ub_
*/
goto Bad_End;
}
- cmd->state = UB_CMDST_CLEAR;
+
+ /*
+ * Having a stall when getting CSW is an error, so
+ * make sure uppper levels are not oblivious to it.
+ */
+ cmd->error = -EIO; /* A cheap trick... */
+
+ cmd->state = UB_CMDST_CLRRS;
ub_cmdtr_state(sc, cmd);
return;
}
+ if (urb->status == -EOVERFLOW) {
+ /*
+ * XXX We are screwed here. Retrying is pointless,
+ * because the pipelined data will not get in until
+ * we read with a big enough buffer. We must reset XXX.
+ */
+ goto Bad_End;
+ }
if (urb->status != 0)
goto Bad_End;
if (urb->actual_length == 0) {
- /*
- * Some broken devices add unnecessary zero-length
- * packets to the end of their data transfers.
- * Such packets show up as 0-length CSWs. If we
- * encounter such a thing, try to read the CSW again.
- */
- if (++cmd->stat_count >= 4) {
- printk(KERN_NOTICE "%s: unable to get CSW\n",
- sc->name);
- goto Bad_End;
- }
- __ub_state_stat(sc, cmd);
+ ub_state_stat_counted(sc, cmd);
return;
}
/*
* Check the returned Bulk protocol status.
+ * The status block has to be validated first.
*/
bcs = &sc->work_bcs;
- rc = le32_to_cpu(bcs->Residue);
- if (rc != cmd->len - cmd->act_len) {
+
+ if (sc->signature == cpu_to_le32(0)) {
/*
- * It is all right to transfer less, the caller has
- * to check. But it's not all right if the device
- * counts disagree with our counts.
+ * This is the first reply, so do not perform the check.
+ * Instead, remember the signature the device uses
+ * for future checks. But do not allow a nul.
*/
- /* P3 */ printk("%s: resid %d len %d act %d\n",
- sc->name, rc, cmd->len, cmd->act_len);
- goto Bad_End;
- }
-
-#if 0
- if (bcs->Signature != cpu_to_le32(US_BULK_CS_SIGN) &&
- bcs->Signature != cpu_to_le32(US_BULK_CS_OLYMPUS_SIGN)) {
- /* Windows ignores signatures, so do we. */
+ sc->signature = bcs->Signature;
+ if (sc->signature == cpu_to_le32(0)) {
+ ub_state_stat_counted(sc, cmd);
+ return;
+ }
+ } else {
+ if (bcs->Signature != sc->signature) {
+ ub_state_stat_counted(sc, cmd);
+ return;
+ }
}
-#endif
if (bcs->Tag != cmd->tag) {
/*
@@ -1245,16 +1342,22 @@ static void ub_scsi_urb_compl(struct ub_
* commands and reply at commands we timed out before.
* Without flushing these replies we loop forever.
*/
- if (++cmd->stat_count >= 4) {
- printk(KERN_NOTICE "%s: "
- "tag mismatch orig 0x%x reply 0x%x\n",
- sc->name, cmd->tag, bcs->Tag);
- goto Bad_End;
- }
- __ub_state_stat(sc, cmd);
+ ub_state_stat_counted(sc, cmd);
return;
}
+ rc = le32_to_cpu(bcs->Residue);
+ if (rc != cmd->len - cmd->act_len) {
+ /*
+ * It is all right to transfer less, the caller has
+ * to check. But it's not all right if the device
+ * counts disagree with our counts.
+ */
+ /* P3 */ printk("%s: resid %d len %d act %d\n",
+ sc->name, rc, cmd->len, cmd->act_len);
+ goto Bad_End;
+ }
+
switch (bcs->Status) {
case US_BULK_STAT_OK:
break;
@@ -1272,6 +1375,10 @@ static void ub_scsi_urb_compl(struct ub_
}
/* Not zeroing error to preserve a babble indicator */
+ if (cmd->error != 0) {
+ ub_state_sense(sc, cmd);
+ return;
+ }
cmd->state = UB_CMDST_DONE;
ub_cmdtr_state(sc, cmd);
ub_cmdq_pop(sc);
@@ -1310,7 +1417,7 @@ static void ub_state_done(struct ub_dev
* Factorization helper for the command state machine:
* Submit a CSW read.
*/
-static void __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
int rc;
@@ -1328,11 +1435,12 @@ static void __ub_state_stat(struct ub_de
/* XXX Clear stalls */
ub_complete(&sc->work_done);
ub_state_done(sc, cmd, rc);
- return;
+ return -1;
}
sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
add_timer(&sc->work_timer);
+ return 0;
}
/*
@@ -1341,7 +1449,9 @@ static void __ub_state_stat(struct ub_de
*/
static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
- __ub_state_stat(sc, cmd);
+
+ if (__ub_state_stat(sc, cmd) != 0)
+ return;
cmd->stat_count = 0;
cmd->state = UB_CMDST_STAT;
@@ -1350,6 +1460,25 @@ static void ub_state_stat(struct ub_dev
/*
* Factorization helper for the command state machine:
+ * Submit a CSW read and go to STAT state with counter (along [C] path).
+ */
+static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+
+ if (++cmd->stat_count >= 4) {
+ ub_state_sense(sc, cmd);
+ return;
+ }
+
+ if (__ub_state_stat(sc, cmd) != 0)
+ return;
+
+ cmd->state = UB_CMDST_STAT;
+ ub_cmdtr_state(sc, cmd);
+}
+
+/*
+ * Factorization helper for the command state machine:
* Submit a REQUEST SENSE and go to SENSE state.
*/
static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
-
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