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mac_scsi: Fix pseudo DMA implementation 

Fix various issues: Comments about bus errors are incorrect. The
PDMA asm must return the size of the memory access that faulted so the
transfer count can be adjusted accordingly. A phase change may cause a
bus error but should not be treated as failure. A bus error does not
always imply a phase change and generally the transfer may continue.
Scatter/gather doesn't seem to work with PDMA due to overruns. This is
a pity because peak throughput seems to double with SG_ALL.
Tested on a Mac LC III and a PowerBook 520.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Finn Thain 2016-03-23 21:10:31 +11:00 committed by Martin K. Petersen
parent ded155b5e4
commit 3a0f64bfa9
2 changed files with 110 additions and 86 deletions
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2
drivers/scsi/NCR5380.h
View File

@ -292,6 +292,8 @@ static void NCR5380_reselect(struct Scsi_Host *instance);
static struct scsi_cmnd *NCR5380_select(struct Scsi_Host *, struct scsi_cmnd *);
static int NCR5380_transfer_dma(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data);
static int NCR5380_transfer_pio(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data);
static int NCR5380_poll_politely(struct Scsi_Host *, int, int, int, int);
static int NCR5380_poll_politely2(struct Scsi_Host *, int, int, int, int, int, int, int);
#endif /* __KERNEL__ */
#endif /* NCR5380_H */

194
drivers/scsi/mac_scsi.c
View File

@ -28,7 +28,8 @@
/* Definitions for the core NCR5380 driver. */
#define NCR5380_implementation_fields unsigned char *pdma_base
#define NCR5380_implementation_fields unsigned char *pdma_base; \
int pdma_residual
#define NCR5380_read(reg) macscsi_read(instance, reg)
#define NCR5380_write(reg, value) macscsi_write(instance, reg, value)
@ -37,7 +38,7 @@
macscsi_dma_xfer_len(instance, cmd)
#define NCR5380_dma_recv_setup macscsi_pread
#define NCR5380_dma_send_setup macscsi_pwrite
#define NCR5380_dma_residual(instance) (0)
#define NCR5380_dma_residual(instance) (hostdata->pdma_residual)
#define NCR5380_intr macscsi_intr
#define NCR5380_queue_command macscsi_queue_command
@ -104,18 +105,9 @@ static int __init mac_scsi_setup(char *str)
__setup("mac5380=", mac_scsi_setup);
#endif /* !MODULE */
/*
Pseudo-DMA: (Ove Edlund)
The code attempts to catch bus errors that occur if one for example
"trips over the cable".
XXX: Since bus errors in the PDMA routines never happen on my
computer, the bus error code is untested.
If the code works as intended, a bus error results in Pseudo-DMA
being disabled, meaning that the driver switches to slow handshake.
If bus errors are NOT extremely rare, this has to be changed.
*/
/* Pseudo DMA asm originally by Ove Edlund */
#define CP_IO_TO_MEM(s,d,len) \
#define CP_IO_TO_MEM(s,d,n) \
__asm__ __volatile__ \
(" cmp.w #4,%2\n" \
" bls 8f\n" \
@ -152,61 +144,73 @@ __asm__ __volatile__ \
" 9: \n" \
".section .fixup,\"ax\"\n" \
" .even\n" \
"90: moveq.l #1, %2\n" \
"91: moveq.l #1, %2\n" \
" jra 9b\n" \
"94: moveq.l #4, %2\n" \
" jra 9b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 4\n" \
" .long 1b,90b\n" \
" .long 3b,90b\n" \
" .long 31b,90b\n" \
" .long 32b,90b\n" \
" .long 33b,90b\n" \
" .long 34b,90b\n" \
" .long 35b,90b\n" \
" .long 36b,90b\n" \
" .long 37b,90b\n" \
" .long 5b,90b\n" \
" .long 7b,90b\n" \
" .long 1b,91b\n" \
" .long 3b,94b\n" \
" .long 31b,94b\n" \
" .long 32b,94b\n" \
" .long 33b,94b\n" \
" .long 34b,94b\n" \
" .long 35b,94b\n" \
" .long 36b,94b\n" \
" .long 37b,94b\n" \
" .long 5b,94b\n" \
" .long 7b,91b\n" \
".previous" \
: "=a"(s), "=a"(d), "=d"(len) \
: "0"(s), "1"(d), "2"(len) \
: "=a"(s), "=a"(d), "=d"(n) \
: "0"(s), "1"(d), "2"(n) \
: "d0")
static int macscsi_pread(struct Scsi_Host *instance,
unsigned char *dst, int len)
{
struct NCR5380_hostdata *hostdata = shost_priv(instance);
unsigned char *d;
unsigned char *s;
unsigned char *s = hostdata->pdma_base + (INPUT_DATA_REG << 4);
unsigned char *d = dst;
int n = len;
int transferred;
s = hostdata->pdma_base + (INPUT_DATA_REG << 4);
d = dst;
while (!NCR5380_poll_politely(instance, BUS_AND_STATUS_REG,
BASR_DRQ | BASR_PHASE_MATCH,
BASR_DRQ | BASR_PHASE_MATCH, HZ / 64)) {
CP_IO_TO_MEM(s, d, n);
/* These conditions are derived from MacOS */
transferred = d - dst - n;
hostdata->pdma_residual = len - transferred;
while (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ) &&
!(NCR5380_read(STATUS_REG) & SR_REQ))
;
/* No bus error. */
if (n == 0)
return 0;
if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ) &&
(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH)) {
pr_err("Error in macscsi_pread\n");
return -1;
/* Target changed phase early? */
if (NCR5380_poll_politely2(instance, STATUS_REG, SR_REQ, SR_REQ,
BUS_AND_STATUS_REG, BASR_ACK, BASR_ACK, HZ / 64) < 0)
scmd_printk(KERN_ERR, hostdata->connected,
"%s: !REQ and !ACK\n", __func__);
if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH))
return 0;
dsprintk(NDEBUG_PSEUDO_DMA, instance,
"%s: bus error (%d/%d)\n", __func__, transferred, len);
NCR5380_dprint(NDEBUG_PSEUDO_DMA, instance);
d = dst + transferred;
n = len - transferred;
}
CP_IO_TO_MEM(s, d, len);
if (len != 0) {
pr_notice("Bus error in macscsi_pread\n");
return -1;
}
return 0;
scmd_printk(KERN_ERR, hostdata->connected,
"%s: phase mismatch or !DRQ\n", __func__);
NCR5380_dprint(NDEBUG_PSEUDO_DMA, instance);
return -1;
}
#define CP_MEM_TO_IO(s,d,len) \
#define CP_MEM_TO_IO(s,d,n) \
__asm__ __volatile__ \
(" cmp.w #4,%2\n" \
" bls 8f\n" \
@ -243,57 +247,76 @@ __asm__ __volatile__ \
" 9: \n" \
".section .fixup,\"ax\"\n" \
" .even\n" \
"90: moveq.l #1, %2\n" \
"91: moveq.l #1, %2\n" \
" jra 9b\n" \
"94: moveq.l #4, %2\n" \
" jra 9b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 4\n" \
" .long 1b,90b\n" \
" .long 3b,90b\n" \
" .long 31b,90b\n" \
" .long 32b,90b\n" \
" .long 33b,90b\n" \
" .long 34b,90b\n" \
" .long 35b,90b\n" \
" .long 36b,90b\n" \
" .long 37b,90b\n" \
" .long 5b,90b\n" \
" .long 7b,90b\n" \
" .long 1b,91b\n" \
" .long 3b,94b\n" \
" .long 31b,94b\n" \
" .long 32b,94b\n" \
" .long 33b,94b\n" \
" .long 34b,94b\n" \
" .long 35b,94b\n" \
" .long 36b,94b\n" \
" .long 37b,94b\n" \
" .long 5b,94b\n" \
" .long 7b,91b\n" \
".previous" \
: "=a"(s), "=a"(d), "=d"(len) \
: "0"(s), "1"(d), "2"(len) \
: "=a"(s), "=a"(d), "=d"(n) \
: "0"(s), "1"(d), "2"(n) \
: "d0")
static int macscsi_pwrite(struct Scsi_Host *instance,
unsigned char *src, int len)
{
struct NCR5380_hostdata *hostdata = shost_priv(instance);
unsigned char *s;
unsigned char *d;
unsigned char *s = src;
unsigned char *d = hostdata->pdma_base + (OUTPUT_DATA_REG << 4);
int n = len;
int transferred;
s = src;
d = hostdata->pdma_base + (OUTPUT_DATA_REG << 4);
while (!NCR5380_poll_politely(instance, BUS_AND_STATUS_REG,
BASR_DRQ | BASR_PHASE_MATCH,
BASR_DRQ | BASR_PHASE_MATCH, HZ / 64)) {
CP_MEM_TO_IO(s, d, n);
/* These conditions are derived from MacOS */
transferred = s - src - n;
hostdata->pdma_residual = len - transferred;
while (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ) &&
(!(NCR5380_read(STATUS_REG) & SR_REQ) ||
(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH)))
;
/* Target changed phase early? */
if (NCR5380_poll_politely2(instance, STATUS_REG, SR_REQ, SR_REQ,
BUS_AND_STATUS_REG, BASR_ACK, BASR_ACK, HZ / 64) < 0)
scmd_printk(KERN_ERR, hostdata->connected,
"%s: !REQ and !ACK\n", __func__);
if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH))
return 0;
if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ)) {
pr_err("Error in macscsi_pwrite\n");
return -1;
/* No bus error. */
if (n == 0) {
if (NCR5380_poll_politely(instance, TARGET_COMMAND_REG,
TCR_LAST_BYTE_SENT,
TCR_LAST_BYTE_SENT, HZ / 64) < 0)
scmd_printk(KERN_ERR, hostdata->connected,
"%s: Last Byte Sent timeout\n", __func__);
return 0;
}
dsprintk(NDEBUG_PSEUDO_DMA, instance,
"%s: bus error (%d/%d)\n", __func__, transferred, len);
NCR5380_dprint(NDEBUG_PSEUDO_DMA, instance);
s = src + transferred;
n = len - transferred;
}
CP_MEM_TO_IO(s, d, len);
scmd_printk(KERN_ERR, hostdata->connected,
"%s: phase mismatch or !DRQ\n", __func__);
NCR5380_dprint(NDEBUG_PSEUDO_DMA, instance);
if (len != 0) {
pr_notice("Bus error in macscsi_pwrite\n");
return -1;
}
return 0;
return -1;
}
static int macscsi_dma_xfer_len(struct Scsi_Host *instance,
@ -301,10 +324,11 @@ static int macscsi_dma_xfer_len(struct Scsi_Host *instance,
{
struct NCR5380_hostdata *hostdata = shost_priv(instance);
if (hostdata->flags & FLAG_NO_PSEUDO_DMA)
if (hostdata->flags & FLAG_NO_PSEUDO_DMA ||
cmd->SCp.this_residual < 16)
return 0;
return cmd->transfersize;
return cmd->SCp.this_residual;
}
#include "NCR5380.c"
@ -322,7 +346,7 @@ static struct scsi_host_template mac_scsi_template = {
.eh_bus_reset_handler = macscsi_bus_reset,
.can_queue = 16,
.this_id = 7,
.sg_tablesize = SG_ALL,
.sg_tablesize = 1,
.cmd_per_lun = 2,
.use_clustering = DISABLE_CLUSTERING,
.cmd_size = NCR5380_CMD_SIZE,
@ -358,8 +382,6 @@ static int __init mac_scsi_probe(struct platform_device *pdev)
mac_scsi_template.sg_tablesize = setup_sg_tablesize;
if (setup_hostid >= 0)
mac_scsi_template.this_id = setup_hostid & 7;
if (setup_use_pdma < 0)
setup_use_pdma = 0;
instance = scsi_host_alloc(&mac_scsi_template,
sizeof(struct NCR5380_hostdata));