[RFC PATCH 76/71] ncr5380: Enable PDMA for DTC chips

Ondrej Zary
2015-12-03T23:03:00Z

Add I/O register mapping for DTC chips and enable PDMA mode.

These chips have 16-bit wide HOST BUFFER register (counter register at
offset 0x0d increments by 2 on each HOST BUFFER read).

Large PIO transfers crash at least the DTCT-436P chip (all reads result
in 0xFF) so this patch actually makes it work.

The chip also crashes when we bang the C400 host status register too
heavily after PDMA write - a small udelay is needed.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
---
# hdparm -t --direct /dev/sdb

/dev/sdb:
Timing O_DIRECT disk reads: 4 MB in 3.78 seconds = 1.06 MB/sec

drivers/scsi/NCR5380.h | 1 +
drivers/scsi/g_NCR5380.c | 47 +++++++++++++++++++++++-----------------------
2 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/drivers/scsi/NCR5380.h b/drivers/scsi/NCR5380.h
index 5092580..e3b8149 100644
--- a/drivers/scsi/NCR5380.h
+++ b/drivers/scsi/NCR5380.h
@@ -222,6 +222,7 @@

#define FLAG_NO_DMA_FIXUP 1 /* No DMA errata workarounds */
#define FLAG_NO_PSEUDO_DMA 8 /* Inhibit DMA */
+#define FLAG_16BIT 16 /* 16-bit PDMA */
#define FLAG_LATE_DMA_SETUP 32 /* Setup NCR before DMA H/W */
#define FLAG_TAGGED_QUEUING 64 /* as X3T9.2 spelled it */
#define FLAG_TOSHIBA_DELAY 128 /* Allow for borken CD-ROMs */
diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index fae4332..04f6c29 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -331,7 +331,7 @@ static int __init generic_NCR5380_detect(struct scsi_host_template *tpnt)
ports = ncr_53c400a_ports;
break;
case BOARD_DTC3181E:
- flags = FLAG_NO_PSEUDO_DMA;
+ flags = FLAG_NO_DMA_FIXUP | FLAG_16BIT;
ports = dtc_3181e_ports;
break;
}
@@ -415,7 +415,8 @@ static int __init generic_NCR5380_detect(struct scsi_host_template *tpnt)
hostdata->c400_blk_cnt = 1;
hostdata->c400_host_buf = 4;
}
- if (overrides[current_override].board == BOARD_NCR53C400A) {
+ if (overrides[current_override].board == BOARD_NCR53C400A ||
+ overrides[current_override].board == BOARD_DTC3181E) {
hostdata->c400_ctl_status = 9;
hostdata->c400_blk_cnt = 10;
hostdata->c400_host_buf = 8;
@@ -434,7 +435,8 @@ static int __init generic_NCR5380_detect(struct scsi_host_template *tpnt)
goto out_unregister;

if (overrides[current_override].board == BOARD_NCR53C400 ||
- overrides[current_override].board == BOARD_NCR53C400A)
+ overrides[current_override].board == BOARD_NCR53C400A ||
+ overrides[current_override].board == BOARD_DTC3181E)
NCR5380_write(hostdata->c400_ctl_status, CSR_BASE);

NCR5380_maybe_reset_bus(instance);
@@ -561,11 +563,10 @@ static inline int NCR5380_pread(struct Scsi_Host *instance, unsigned char *dst,
while (NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY);

#ifndef SCSI_G_NCR5380_MEM
- {
- int i;
- for (i = 0; i < 128; i++)
- dst[start + i] = NCR5380_read(hostdata->c400_host_buf);
- }
+ if (hostdata->flags & FLAG_16BIT)
+ insw(instance->io_port + hostdata->c400_host_buf, dst + start, 64);
+ else
+ insb(instance->io_port + hostdata->c400_host_buf, dst + start, 128);
#else
/* implies SCSI_G_NCR5380_MEM */
memcpy_fromio(dst + start,
@@ -582,11 +583,10 @@ static inline int NCR5380_pread(struct Scsi_Host *instance, unsigned char *dst,
}

#ifndef SCSI_G_NCR5380_MEM
- {
- int i;
- for (i = 0; i < 128; i++)
- dst[start + i] = NCR5380_read(hostdata->c400_host_buf);
- }
+ if (hostdata->flags & FLAG_16BIT)
+ insw(instance->io_port + hostdata->c400_host_buf, dst + start, 64);
+ else
+ insb(instance->io_port + hostdata->c400_host_buf, dst + start, 128);
#else
/* implies SCSI_G_NCR5380_MEM */
memcpy_fromio(dst + start,
@@ -645,10 +645,10 @@ static inline int NCR5380_pwrite(struct Scsi_Host *instance, unsigned char *src,
while (NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY)
; // FIXME - timeout
#ifndef SCSI_G_NCR5380_MEM
- {
- for (i = 0; i < 128; i++)
- NCR5380_write(hostdata->c400_host_buf, src[start + i]);
- }
+ if (hostdata->flags & FLAG_16BIT)
+ outsw(instance->io_port + hostdata->c400_host_buf, src + start, 64);
+ else
+ outsb(instance->io_port + hostdata->c400_host_buf, src + start, 128);
#else
/* implies SCSI_G_NCR5380_MEM */
memcpy_toio(hostdata->iomem + NCR53C400_host_buffer,
@@ -660,12 +660,11 @@ static inline int NCR5380_pwrite(struct Scsi_Host *instance, unsigned char *src,
if (blocks) {
while (NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY)
; // FIXME - no timeout
-
#ifndef SCSI_G_NCR5380_MEM
- {
- for (i = 0; i < 128; i++)
- NCR5380_write(hostdata->c400_host_buf, src[start + i]);
- }
+ if (hostdata->flags & FLAG_16BIT)
+ outsw(instance->io_port + hostdata->c400_host_buf, src + start, 64);
+ else
+ outsb(instance->io_port + hostdata->c400_host_buf, src + start, 128);
#else
/* implies SCSI_G_NCR5380_MEM */
memcpy_toio(hostdata->iomem + NCR53C400_host_buffer,
@@ -685,8 +684,10 @@ static inline int NCR5380_pwrite(struct Scsi_Host *instance, unsigned char *src,
/* All documentation says to check for this. Maybe my hardware is too
* fast. Waiting for it seems to work fine! KLL
*/
- while (!(i = NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ))
+ while (!(i = NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ)) {
+ udelay(4); /* DTC436 chip hangs without this */
; // FIXME - no timeout
+ }

/*
* I know. i is certainly != 0 here but the loop is new. See previous
--
Ondrej Zary