[PATCH v3 09/23] ncr5380: Adopt uniform DMA setup convention

Finn Thain
2016-03-21T02:31:58Z

[-- Attachment #1: ncr5380-dma-setup-api --]
[-- Type: text/plain, Size: 5992 bytes --]

Standardize the DMA setup hooks so that the DMA implementation in
atari_NCR5380.c can be reconciled with pseudo DMA implementation in
NCR5380.c.

Calls to NCR5380_dma_recv_setup() and NCR5380_dma_send_setup() return
a negative value on failure, zero on PDMA transfer success and a positive
byte count for DMA setup success.

This convention is not entirely new, but is now applied consistently.

Also remove a pointless Status Register access: the *phase assignment is
redundant because after NCR5380_transfer_dma() returns control to
NCR5380_information_transfer(), that routine then returns control
to NCR5380_main(), which means *phase is dead.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>

---
drivers/scsi/NCR5380.c | 21 ++++++++++-----------
drivers/scsi/arm/cumana_1.c | 10 ++++++++--
drivers/scsi/arm/oak.c | 4 ++--
drivers/scsi/atari_scsi.c | 3 ---
4 files changed, 20 insertions(+), 18 deletions(-)

Index: linux/drivers/scsi/NCR5380.c
===================================================================
--- linux.orig/drivers/scsi/NCR5380.c 2016-03-21 13:31:21.000000000 +1100
+++ linux/drivers/scsi/NCR5380.c 2016-03-21 13:31:25.000000000 +1100
@@ -1431,7 +1431,7 @@ static int NCR5380_transfer_dma(struct S
register unsigned char p = *phase;
register unsigned char *d = *data;
unsigned char tmp;
- int foo;
+ int result;

if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
*phase = tmp;
@@ -1505,9 +1505,9 @@ static int NCR5380_transfer_dma(struct S
*/

if (p & SR_IO) {
- foo = NCR5380_dma_recv_setup(instance, d,
+ result = NCR5380_dma_recv_setup(instance, d,
hostdata->flags & FLAG_DMA_FIXUP ? c - 1 : c);
- if (!foo && (hostdata->flags & FLAG_DMA_FIXUP)) {
+ if (!result && (hostdata->flags & FLAG_DMA_FIXUP)) {
/*
* The workaround was to transfer fewer bytes than we
* intended to with the pseudo-DMA read function, wait for
@@ -1525,19 +1525,19 @@ static int NCR5380_transfer_dma(struct S

if (NCR5380_poll_politely(instance, BUS_AND_STATUS_REG,
BASR_DRQ, BASR_DRQ, HZ) < 0) {
- foo = -1;
+ result = -1;
shost_printk(KERN_ERR, instance, "PDMA read: DRQ timeout\n");
}
if (NCR5380_poll_politely(instance, STATUS_REG,
SR_REQ, 0, HZ) < 0) {
- foo = -1;
+ result = -1;
shost_printk(KERN_ERR, instance, "PDMA read: !REQ timeout\n");
}
d[c - 1] = NCR5380_read(INPUT_DATA_REG);
}
} else {
- foo = NCR5380_dma_send_setup(instance, d, c);
- if (!foo && (hostdata->flags & FLAG_DMA_FIXUP)) {
+ result = NCR5380_dma_send_setup(instance, d, c);
+ if (!result && (hostdata->flags & FLAG_DMA_FIXUP)) {
/*
* 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.
@@ -1545,7 +1545,7 @@ static int NCR5380_transfer_dma(struct S
if (NCR5380_poll_politely2(instance,
BUS_AND_STATUS_REG, BASR_DRQ, BASR_DRQ,
BUS_AND_STATUS_REG, BASR_PHASE_MATCH, 0, HZ) < 0) {
- foo = -1;
+ result = -1;
shost_printk(KERN_ERR, instance, "PDMA write: DRQ and phase timeout\n");
}
}
@@ -1555,8 +1555,7 @@ static int NCR5380_transfer_dma(struct S
NCR5380_read(RESET_PARITY_INTERRUPT_REG);
*data = d + c;
*count = 0;
- *phase = NCR5380_read(STATUS_REG) & PHASE_MASK;
- return foo;
+ return result;
}

/*
@@ -1652,7 +1651,7 @@ static void NCR5380_information_transfer
if (!cmd->device->borken)
transfersize = NCR5380_dma_xfer_len(instance, cmd, phase);

- if (transfersize) {
+ if (transfersize > 0) {
len = transfersize;
if (NCR5380_transfer_dma(instance, &phase,
&len, (unsigned char **)&cmd->SCp.ptr)) {
Index: linux/drivers/scsi/arm/cumana_1.c
===================================================================
--- linux.orig/drivers/scsi/arm/cumana_1.c 2016-03-21 13:31:21.000000000 +1100
+++ linux/drivers/scsi/arm/cumana_1.c 2016-03-21 13:31:25.000000000 +1100
@@ -101,7 +101,10 @@ static inline int cumanascsi_pwrite(stru
}
end:
writeb(priv(host)->ctrl | 0x40, priv(host)->base + CTRL);
- return len;
+
+ if (len)
+ return -1;
+ return 0;
}

static inline int cumanascsi_pread(struct Scsi_Host *host,
@@ -163,7 +166,10 @@ static inline int cumanascsi_pread(struc
}
end:
writeb(priv(host)->ctrl | 0x40, priv(host)->base + CTRL);
- return len;
+
+ if (len)
+ return -1;
+ return 0;
}

static unsigned char cumanascsi_read(struct Scsi_Host *host, unsigned int reg)
Index: linux/drivers/scsi/arm/oak.c
===================================================================
--- linux.orig/drivers/scsi/arm/oak.c 2016-03-21 13:31:21.000000000 +1100
+++ linux/drivers/scsi/arm/oak.c 2016-03-21 13:31:25.000000000 +1100
@@ -47,13 +47,13 @@ static inline int oakscsi_pwrite(struct
void __iomem *base = priv(instance)->base;

printk("writing %p len %d\n",addr, len);
- if(!len) return -1;

while(1)
{
int status;
while (((status = readw(base + STAT)) & 0x100)==0);
}
+ return 0;
}

static inline int oakscsi_pread(struct Scsi_Host *instance,
@@ -74,7 +74,7 @@ printk("reading %p len %d\n", addr, len)
if(status & 0x200 || !timeout)
{
printk("status = %08X\n", status);
- return 1;
+ return -1;
}
}

Index: linux/drivers/scsi/atari_scsi.c
===================================================================
--- linux.orig/drivers/scsi/atari_scsi.c 2016-03-21 13:31:13.000000000 +1100
+++ linux/drivers/scsi/atari_scsi.c 2016-03-21 13:31:25.000000000 +1100
@@ -527,9 +527,6 @@ static unsigned long atari_scsi_dma_setu
*/
dma_cache_maintenance(addr, count, dir);

- if (count == 0)
- printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
-
if (IS_A_TT()) {
tt_scsi_dma.dma_ctrl = dir;
SCSI_DMA_WRITE_P(dma_addr, addr);