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scsi: mac_scsi: Enable PDMA on Mac IIfx

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Add support for Apple's custom "SCSI DMA" chip. This patch doesn't make use
of its DMA capability. Just the PDMA capability is sufficient to improve
sequential read throughput by a factor of 5.

Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Joshua Thompson <funaho@jurai.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Finn Thain
2019-06-09 11:19:11 +10:00
committed by Martin K. Petersen
parent 78ff751f8e
commit 8fb9a64eb6
2 changed files with 47 additions and 10 deletions
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10
arch/m68k/mac/config.c
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@@ -911,6 +911,10 @@ static const struct resource mac_scsi_iifx_rsrc[] __initconst = {
.flags = IORESOURCE_MEM,
.start = 0x50008000,
.end = 0x50009FFF,
}, {
.flags = IORESOURCE_MEM,
.start = 0x50008000,
.end = 0x50009FFF,
},
};
@@ -1012,10 +1016,12 @@ int __init mac_platform_init(void)
case MAC_SCSI_IIFX:
/* Addresses from The Guide to Mac Family Hardware.
* $5000 8000 - $5000 9FFF: SCSI DMA
* $5000 A000 - $5000 BFFF: Alternate SCSI
* $5000 C000 - $5000 DFFF: Alternate SCSI (DMA)
* $5000 E000 - $5000 FFFF: Alternate SCSI (Hsk)
* The SCSI DMA custom IC embeds the 53C80 core. mac_scsi does
* not make use of its DMA or hardware handshaking logic.
* The A/UX header file sys/uconfig.h says $50F0 8000.
* The "SCSI DMA" custom IC embeds the 53C80 core and
* supports Programmed IO, DMA and PDMA (hardware handshake).
*/
platform_device_register_simple("mac_scsi", 0,
mac_scsi_iifx_rsrc, ARRAY_SIZE(mac_scsi_iifx_rsrc));