diff options
Diffstat (limited to 'drivers/scsi/NCR5380.c')
| -rw-r--r-- | drivers/scsi/NCR5380.c | 233 |
1 files changed, 116 insertions, 117 deletions
diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c index cea3a79d538e..0e10502660de 100644 --- a/drivers/scsi/NCR5380.c +++ b/drivers/scsi/NCR5380.c @@ -157,7 +157,6 @@ static inline void initialize_SCp(struct scsi_cmnd *cmd) } ncmd->status = 0; - ncmd->message = 0; } static inline void advance_sg_buffer(struct NCR5380_cmd *ncmd) @@ -199,7 +198,6 @@ static inline void set_resid_from_SCp(struct scsi_cmnd *cmd) * Polls the chip in a reasonably efficient manner waiting for an * event to occur. After a short quick poll we begin to yield the CPU * (if possible). In irq contexts the time-out is arbitrarily limited. - * Callers may hold locks as long as they are held in irq mode. * * Returns 0 if either or both event(s) occurred otherwise -ETIMEDOUT. */ @@ -1228,24 +1226,15 @@ out: return ret; } -/* - * Function : int NCR5380_transfer_pio (struct Scsi_Host *instance, - * unsigned char *phase, int *count, unsigned char **data) - * - * Purpose : transfers data in given phase using polled I/O - * - * Inputs : instance - instance of driver, *phase - pointer to - * what phase is expected, *count - pointer to number of - * bytes to transfer, **data - pointer to data pointer, - * can_sleep - 1 or 0 when sleeping is permitted or not, respectively. - * - * Returns : -1 when different phase is entered without transferring - * maximum number of bytes, 0 if all bytes are transferred or exit - * is in same phase. - * - * Also, *phase, *count, *data are modified in place. +/** + * NCR5380_transfer_pio() - transfers data in given phase using polled I/O + * @instance: instance of driver + * @phase: pointer to what phase is expected + * @count: pointer to number of bytes to transfer + * @data: pointer to data pointer + * @can_sleep: 1 or 0 when sleeping is permitted or not, respectively * - * XXX Note : handling for bus free may be useful. + * Returns: void. *phase, *count, *data are modified in place. */ /* @@ -1254,9 +1243,9 @@ out: * counts, we will always do a pseudo DMA or DMA transfer. */ -static int NCR5380_transfer_pio(struct Scsi_Host *instance, - unsigned char *phase, int *count, - unsigned char **data, unsigned int can_sleep) +static void NCR5380_transfer_pio(struct Scsi_Host *instance, + unsigned char *phase, int *count, + unsigned char **data, unsigned int can_sleep) { struct NCR5380_hostdata *hostdata = shost_priv(instance); unsigned char p = *phase, tmp; @@ -1277,8 +1266,8 @@ static int NCR5380_transfer_pio(struct Scsi_Host *instance, * valid */ - if (NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ, - HZ * can_sleep) < 0) + if (NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ | SR_BSY, + SR_REQ | SR_BSY, HZ * can_sleep) < 0) break; dsprintk(NDEBUG_HANDSHAKE, instance, "REQ asserted\n"); @@ -1329,17 +1318,19 @@ static int NCR5380_transfer_pio(struct Scsi_Host *instance, dsprintk(NDEBUG_HANDSHAKE, instance, "REQ negated, handshake complete\n"); -/* - * We have several special cases to consider during REQ/ACK handshaking : - * 1. We were in MSGOUT phase, and we are on the last byte of the - * message. ATN must be dropped as ACK is dropped. - * - * 2. We are in a MSGIN phase, and we are on the last byte of the - * message. We must exit with ACK asserted, so that the calling - * code may raise ATN before dropping ACK to reject the message. - * - * 3. ACK and ATN are clear and the target may proceed as normal. - */ + /* + * We have several special cases to consider during REQ/ACK + * handshaking: + * + * 1. We were in MSGOUT phase, and we are on the last byte of + * the message. ATN must be dropped as ACK is dropped. + * + * 2. We are in MSGIN phase, and we are on the last byte of the + * message. We must exit with ACK asserted, so that the calling + * code may raise ATN before dropping ACK to reject the message. + * + * 3. ACK and ATN are clear & the target may proceed as normal. + */ if (!(p == PHASE_MSGIN && c == 1)) { if (p == PHASE_MSGOUT && c > 1) NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN); @@ -1361,11 +1352,6 @@ static int NCR5380_transfer_pio(struct Scsi_Host *instance, *phase = tmp & PHASE_MASK; else *phase = PHASE_UNKNOWN; - - if (!c || (*phase == p)) - return 0; - else - return -1; } /** @@ -1485,6 +1471,7 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance, unsigned char **data) { struct NCR5380_hostdata *hostdata = shost_priv(instance); + struct NCR5380_cmd *ncmd = NCR5380_to_ncmd(hostdata->connected); int c = *count; unsigned char p = *phase; unsigned char *d = *data; @@ -1496,7 +1483,7 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance, return -1; } - NCR5380_to_ncmd(hostdata->connected)->phase = p; + ncmd->phase = p; if (p & SR_IO) { if (hostdata->read_overruns) @@ -1574,79 +1561,80 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance, /* The result is zero iff pseudo DMA send/receive was completed. */ hostdata->dma_len = c; -/* - * A note regarding the DMA errata workarounds for early NMOS silicon. - * - * For DMA sends, we want to wait until the last byte has been - * transferred out over the bus before we turn off DMA mode. Alas, there - * seems to be no terribly good way of doing this on a 5380 under all - * conditions. For non-scatter-gather operations, we can wait until REQ - * and ACK both go false, or until a phase mismatch occurs. Gather-sends - * are nastier, since the device will be expecting more data than we - * are prepared to send it, and REQ will remain asserted. On a 53C8[01] we - * could test Last Byte Sent to assure transfer (I imagine this is precisely - * why this signal was added to the newer chips) but on the older 538[01] - * this signal does not exist. The workaround for this lack is a watchdog; - * we bail out of the wait-loop after a modest amount of wait-time if - * the usual exit conditions are not met. Not a terribly clean or - * correct solution :-% - * - * DMA receive is equally tricky due to a nasty characteristic of the NCR5380. - * If the chip is in DMA receive mode, it will respond to a target's - * REQ by latching the SCSI data into the INPUT DATA register and asserting - * ACK, even if it has _already_ been notified by the DMA controller that - * the current DMA transfer has completed! If the NCR5380 is then taken - * out of DMA mode, this already-acknowledged byte is lost. This is - * not a problem for "one DMA transfer per READ command", because - * the situation will never arise... either all of the data is DMA'ed - * properly, or the target switches to MESSAGE IN phase to signal a - * disconnection (either operation bringing the DMA to a clean halt). - * However, in order to handle scatter-receive, we must work around the - * problem. The chosen fix is to DMA fewer bytes, then check for the - * condition before taking the NCR5380 out of DMA mode. One or two extra - * bytes are transferred via PIO as necessary to fill out the original - * request. - */ - - if (hostdata->flags & FLAG_DMA_FIXUP) { - if (p & SR_IO) { - /* - * The workaround was to transfer fewer bytes than we - * intended to with the pseudo-DMA read function, wait for - * the chip to latch the last byte, read it, and then disable - * pseudo-DMA mode. - * - * After REQ is asserted, the NCR5380 asserts DRQ and ACK. - * REQ is deasserted when ACK is asserted, and not reasserted - * until ACK goes false. Since the NCR5380 won't lower ACK - * until DACK is asserted, which won't happen unless we twiddle - * the DMA port or we take the NCR5380 out of DMA mode, we - * can guarantee that we won't handshake another extra - * byte. - */ + /* + * A note regarding the DMA errata workarounds for early NMOS silicon. + * + * For DMA sends, we want to wait until the last byte has been + * transferred out over the bus before we turn off DMA mode. Alas, there + * seems to be no terribly good way of doing this on a 5380 under all + * conditions. For non-scatter-gather operations, we can wait until REQ + * and ACK both go false, or until a phase mismatch occurs. Gather-sends + * are nastier, since the device will be expecting more data than we + * are prepared to send it, and REQ will remain asserted. On a 53C8[01] + * we could test Last Byte Sent to assure transfer (I imagine this is + * precisely why this signal was added to the newer chips) but on the + * older 538[01] this signal does not exist. The workaround for this + * lack is a watchdog; we bail out of the wait-loop after a modest + * amount of wait-time if the usual exit conditions are not met. + * Not a terribly clean or correct solution :-% + * + * DMA receive is equally tricky due to a nasty characteristic of the + * NCR5380. If the chip is in DMA receive mode, it will respond to a + * target's REQ by latching the SCSI data into the INPUT DATA register + * and asserting ACK, even if it has _already_ been notified by the + * DMA controller that the current DMA transfer has completed! If the + * NCR5380 is then taken out of DMA mode, this already-acknowledged + * byte is lost. + * + * This is not a problem for "one DMA transfer per READ + * command", because the situation will never arise... either all of + * the data is DMA'ed properly, or the target switches to MESSAGE IN + * phase to signal a disconnection (either operation bringing the DMA + * to a clean halt). However, in order to handle scatter-receive, we + * must work around the problem. The chosen fix is to DMA fewer bytes, + * then check for the condition before taking the NCR5380 out of DMA + * mode. One or two extra bytes are transferred via PIO as necessary + * to fill out the original request. + */ - if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG, - BASR_DRQ, BASR_DRQ, 0) < 0) { - result = -1; - shost_printk(KERN_ERR, instance, "PDMA read: DRQ timeout\n"); - } - if (NCR5380_poll_politely(hostdata, STATUS_REG, - SR_REQ, 0, 0) < 0) { - result = -1; - shost_printk(KERN_ERR, instance, "PDMA read: !REQ timeout\n"); - } - d[*count - 1] = NCR5380_read(INPUT_DATA_REG); - } else { - /* - * Wait for the last byte to be sent. If REQ is being asserted for - * the byte we're interested, we'll ACK it and it will go false. - */ - if (NCR5380_poll_politely2(hostdata, - BUS_AND_STATUS_REG, BASR_DRQ, BASR_DRQ, - BUS_AND_STATUS_REG, BASR_PHASE_MATCH, 0, 0) < 0) { - result = -1; - shost_printk(KERN_ERR, instance, "PDMA write: DRQ and phase timeout\n"); + if ((hostdata->flags & FLAG_DMA_FIXUP) && + (NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH)) { + /* + * The workaround was to transfer fewer bytes than we + * intended to with the pseudo-DMA receive function, wait for + * the chip to latch the last byte, read it, and then disable + * DMA mode. + * + * After REQ is asserted, the NCR5380 asserts DRQ and ACK. + * REQ is deasserted when ACK is asserted, and not reasserted + * until ACK goes false. Since the NCR5380 won't lower ACK + * until DACK is asserted, which won't happen unless we twiddle + * the DMA port or we take the NCR5380 out of DMA mode, we + * can guarantee that we won't handshake another extra + * byte. + * + * If sending, wait for the last byte to be sent. If REQ is + * being asserted for the byte we're interested, we'll ACK it + * and it will go false. + */ + if (!NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG, + BASR_DRQ, BASR_DRQ, 0)) { + if ((p & SR_IO) && + (NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH)) { + if (!NCR5380_poll_politely(hostdata, STATUS_REG, + SR_REQ, 0, 0)) { + d[c] = NCR5380_read(INPUT_DATA_REG); + --ncmd->this_residual; + } else { + result = -1; + scmd_printk(KERN_ERR, hostdata->connected, + "PDMA fixup: !REQ timeout\n"); + } } + } else if (NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH) { + result = -1; + scmd_printk(KERN_ERR, hostdata->connected, + "PDMA fixup: DRQ timeout\n"); } } @@ -1666,9 +1654,6 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance, * Side effects : SCSI things happen, the disconnected queue will be * modified if a command disconnects, *instance->connected will * change. - * - * XXX Note : we need to watch for bus free or a reset condition here - * to recover from an unexpected bus free condition. */ static void NCR5380_information_transfer(struct Scsi_Host *instance) @@ -1807,9 +1792,11 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance) return; case PHASE_MSGIN: len = 1; + tmp = 0xff; data = &tmp; NCR5380_transfer_pio(instance, &phase, &len, &data, 0); - ncmd->message = tmp; + if (tmp == 0xff) + break; switch (tmp) { case ABORT: @@ -1996,6 +1983,7 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance) break; case PHASE_STATIN: len = 1; + tmp = ncmd->status; data = &tmp; NCR5380_transfer_pio(instance, &phase, &len, &data, 0); ncmd->status = tmp; @@ -2005,9 +1993,20 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance) NCR5380_dprint(NDEBUG_ANY, instance); } /* switch(phase) */ } else { + int err; + spin_unlock_irq(&hostdata->lock); - NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ, HZ); + err = NCR5380_poll_politely(hostdata, STATUS_REG, + SR_REQ, SR_REQ, HZ); spin_lock_irq(&hostdata->lock); + + if (err < 0 && hostdata->connected && + !(NCR5380_read(STATUS_REG) & SR_BSY)) { + scmd_printk(KERN_ERR, hostdata->connected, + "BSY signal lost\n"); + do_reset(instance); + bus_reset_cleanup(instance); + } } } } |