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

From: Finn Thain
Date: Fri Dec 04 2015 - 04:08:46 EST


On Fri, 4 Dec 2015, Ondrej Zary wrote:

> 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@xxxxxxxxxxxxxxxxxxxx>
> ---
> # 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 */

Can we give this a better name? FLAG_16BIT could be taken to mean "16-bit
ISA card" but do we really want a flag for that? How about
FLAG_16BIT_BUF_REG or FLAG_WORD_IO_BUF?

All active flags appear in the console log, thanks to prepare_info(). It
might be helpful to include this one; FLAG_DTC3181E is likely to
disappear.

--

> #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
>
--
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