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linux/drivers/scsi/arm/cumana_1.c
Finn Thain 0a4e361254 ncr5380: Fix soft lockups 
Because of the rudimentary design of the chip, it is necessary to poll the
SCSI bus signals during PIO and this tends to hog the CPU. The driver will
accept new commands while others execute, and this causes a soft lockup
because the workqueue item will not terminate until the issue queue is
emptied.

When exercising dmx3191d using sequential IO from dd, the driver is sent
512 KiB WRITE commands and 128 KiB READs. For a PIO transfer, the rate is
is only about 300 KiB/s, so these are long-running commands. And although
PDMA may run at several MiB/s, interrupts are disabled for the duration
of the transfer.

Fix the unresponsiveness and soft lockup issues by calling cond_resched()
after each command is completed and by limiting max_sectors for drivers
that don't implement real DMA.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-01-06 21:43:09 -05:00

324 lines
7.1 KiB
C
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/*
* Generic Generic NCR5380 driver
*
* Copyright 1995-2002, Russell King
*/
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <asm/ecard.h>
#include <asm/io.h>
#include <scsi/scsi_host.h>
#define PSEUDO_DMA
#define priv(host) ((struct NCR5380_hostdata *)(host)->hostdata)
#define NCR5380_read(reg) cumanascsi_read(instance, reg)
#define NCR5380_write(reg, value) cumanascsi_write(instance, reg, value)
#define NCR5380_dma_xfer_len(instance, cmd, phase) (cmd->transfersize)
#define NCR5380_intr cumanascsi_intr
#define NCR5380_queue_command cumanascsi_queue_command
#define NCR5380_info cumanascsi_info
#define NCR5380_implementation_fields \
unsigned ctrl; \
void __iomem *base; \
void __iomem *dma
#include "../NCR5380.h"
void cumanascsi_setup(char *str, int *ints)
{
}
#define CTRL 0x16fc
#define STAT 0x2004
#define L(v) (((v)<<16)|((v) & 0x0000ffff))
#define H(v) (((v)>>16)|((v) & 0xffff0000))
static inline int
NCR5380_pwrite(struct Scsi_Host *host, unsigned char *addr, int len)
{
unsigned long *laddr;
void __iomem *dma = priv(host)->dma + 0x2000;
if(!len) return 0;
writeb(0x02, priv(host)->base + CTRL);
laddr = (unsigned long *)addr;
while(len >= 32)
{
unsigned int status;
unsigned long v;
status = readb(priv(host)->base + STAT);
if(status & 0x80)
goto end;
if(!(status & 0x40))
continue;
v=*laddr++; writew(L(v), dma); writew(H(v), dma);
v=*laddr++; writew(L(v), dma); writew(H(v), dma);
v=*laddr++; writew(L(v), dma); writew(H(v), dma);
v=*laddr++; writew(L(v), dma); writew(H(v), dma);
v=*laddr++; writew(L(v), dma); writew(H(v), dma);
v=*laddr++; writew(L(v), dma); writew(H(v), dma);
v=*laddr++; writew(L(v), dma); writew(H(v), dma);
v=*laddr++; writew(L(v), dma); writew(H(v), dma);
len -= 32;
if(len == 0)
break;
}
addr = (unsigned char *)laddr;
writeb(0x12, priv(host)->base + CTRL);
while(len > 0)
{
unsigned int status;
status = readb(priv(host)->base + STAT);
if(status & 0x80)
goto end;
if(status & 0x40)
{
writeb(*addr++, dma);
if(--len == 0)
break;
}
status = readb(priv(host)->base + STAT);
if(status & 0x80)
goto end;
if(status & 0x40)
{
writeb(*addr++, dma);
if(--len == 0)
break;
}
}
end:
writeb(priv(host)->ctrl | 0x40, priv(host)->base + CTRL);
return len;
}
static inline int
NCR5380_pread(struct Scsi_Host *host, unsigned char *addr, int len)
{
unsigned long *laddr;
void __iomem *dma = priv(host)->dma + 0x2000;
if(!len) return 0;
writeb(0x00, priv(host)->base + CTRL);
laddr = (unsigned long *)addr;
while(len >= 32)
{
unsigned int status;
status = readb(priv(host)->base + STAT);
if(status & 0x80)
goto end;
if(!(status & 0x40))
continue;
*laddr++ = readw(dma) | (readw(dma) << 16);
*laddr++ = readw(dma) | (readw(dma) << 16);
*laddr++ = readw(dma) | (readw(dma) << 16);
*laddr++ = readw(dma) | (readw(dma) << 16);
*laddr++ = readw(dma) | (readw(dma) << 16);
*laddr++ = readw(dma) | (readw(dma) << 16);
*laddr++ = readw(dma) | (readw(dma) << 16);
*laddr++ = readw(dma) | (readw(dma) << 16);
len -= 32;
if(len == 0)
break;
}
addr = (unsigned char *)laddr;
writeb(0x10, priv(host)->base + CTRL);
while(len > 0)
{
unsigned int status;
status = readb(priv(host)->base + STAT);
if(status & 0x80)
goto end;
if(status & 0x40)
{
*addr++ = readb(dma);
if(--len == 0)
break;
}
status = readb(priv(host)->base + STAT);
if(status & 0x80)
goto end;
if(status & 0x40)
{
*addr++ = readb(dma);
if(--len == 0)
break;
}
}
end:
writeb(priv(host)->ctrl | 0x40, priv(host)->base + CTRL);
return len;
}
static unsigned char cumanascsi_read(struct Scsi_Host *host, unsigned int reg)
{
void __iomem *base = priv(host)->base;
unsigned char val;
writeb(0, base + CTRL);
val = readb(base + 0x2100 + (reg << 2));
priv(host)->ctrl = 0x40;
writeb(0x40, base + CTRL);
return val;
}
static void cumanascsi_write(struct Scsi_Host *host, unsigned int reg, unsigned int value)
{
void __iomem *base = priv(host)->base;
writeb(0, base + CTRL);
writeb(value, base + 0x2100 + (reg << 2));
priv(host)->ctrl = 0x40;
writeb(0x40, base + CTRL);
}
#include "../NCR5380.c"
static struct scsi_host_template cumanascsi_template = {
.module = THIS_MODULE,
.name = "Cumana 16-bit SCSI",
.info = cumanascsi_info,
.queuecommand = cumanascsi_queue_command,
.eh_abort_handler = NCR5380_abort,
.eh_bus_reset_handler = NCR5380_bus_reset,
.can_queue = 16,
.this_id = 7,
.sg_tablesize = SG_ALL,
.cmd_per_lun = 2,
.use_clustering = DISABLE_CLUSTERING,
.proc_name = "CumanaSCSI-1",
.cmd_size = NCR5380_CMD_SIZE,
.max_sectors = 128,
};
static int cumanascsi1_probe(struct expansion_card *ec,
const struct ecard_id *id)
{
struct Scsi_Host *host;
int ret;
ret = ecard_request_resources(ec);
if (ret)
goto out;
host = scsi_host_alloc(&cumanascsi_template, sizeof(struct NCR5380_hostdata));
if (!host) {
ret = -ENOMEM;
goto out_release;
}
priv(host)->base = ioremap(ecard_resource_start(ec, ECARD_RES_IOCSLOW),
ecard_resource_len(ec, ECARD_RES_IOCSLOW));
priv(host)->dma = ioremap(ecard_resource_start(ec, ECARD_RES_MEMC),
ecard_resource_len(ec, ECARD_RES_MEMC));
if (!priv(host)->base || !priv(host)->dma) {
ret = -ENOMEM;
goto out_unmap;
}
host->irq = ec->irq;
ret = NCR5380_init(host, 0);
if (ret)
goto out_unmap;
NCR5380_maybe_reset_bus(host);
priv(host)->ctrl = 0;
writeb(0, priv(host)->base + CTRL);
ret = request_irq(host->irq, cumanascsi_intr, 0,
"CumanaSCSI-1", host);
if (ret) {
printk("scsi%d: IRQ%d not free: %d\n",
host->host_no, host->irq, ret);
goto out_exit;
}
ret = scsi_add_host(host, &ec->dev);
if (ret)
goto out_free_irq;
scsi_scan_host(host);
goto out;
out_free_irq:
free_irq(host->irq, host);
out_exit:
NCR5380_exit(host);
out_unmap:
iounmap(priv(host)->base);
iounmap(priv(host)->dma);
scsi_host_put(host);
out_release:
ecard_release_resources(ec);
out:
return ret;
}
static void cumanascsi1_remove(struct expansion_card *ec)
{
struct Scsi_Host *host = ecard_get_drvdata(ec);
ecard_set_drvdata(ec, NULL);
scsi_remove_host(host);
free_irq(host->irq, host);
NCR5380_exit(host);
iounmap(priv(host)->base);
iounmap(priv(host)->dma);
scsi_host_put(host);
ecard_release_resources(ec);
}
static const struct ecard_id cumanascsi1_cids[] = {
{ MANU_CUMANA, PROD_CUMANA_SCSI_1 },
{ 0xffff, 0xffff }
};
static struct ecard_driver cumanascsi1_driver = {
.probe = cumanascsi1_probe,
.remove = cumanascsi1_remove,
.id_table = cumanascsi1_cids,
.drv = {
.name = "cumanascsi1",
},
};
static int __init cumanascsi_init(void)
{
return ecard_register_driver(&cumanascsi1_driver);
}
static void __exit cumanascsi_exit(void)
{
ecard_remove_driver(&cumanascsi1_driver);
}
module_init(cumanascsi_init);
module_exit(cumanascsi_exit);
MODULE_DESCRIPTION("Cumana SCSI-1 driver for Acorn machines");
MODULE_LICENSE("GPL");
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