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linux/drivers/scsi/mac_scsi.c
Ahmed S. Darwish e7734ef14e scsi: NCR5380: Remove context check 
NCR5380_poll_politely2() uses in_interrupt() and irqs_disabled() to check
if it is safe to sleep.

Such usage in drivers is phased out and Linus clearly requested that code
which changes behaviour depending on context should either be separated, or
the context be explicitly conveyed in an argument passed by the caller.

Below is a context analysis of NCR5380_poll_politely2() uppermost callers:

  - NCR5380_maybe_reset_bus(), task, invoked during device probe.
    -> NCR5380_poll_politely()
    -> do_abort()

  - NCR5380_select(), task, but can only sleep in the "release, then
    re-acquire" regions of the spinlock held by its caller.
    Sleeping invocations (lock released):
    -> NCR5380_poll_politely2()

    Atomic invocations (lock acquired):
    -> NCR5380_reselect()
       -> NCR5380_poll_politely()
       -> do_abort()
       -> NCR5380_transfer_pio()

  - NCR5380_intr(), interrupt handler
    -> NCR5380_dma_complete()
       -> NCR5380_transfer_pio()
	  -> NCR5380_poll_politely()
    -> NCR5380_reselect() (see above)

  - NCR5380_information_transfer(), task, but can only sleep in the
    "release, then re-acquire" regions of the caller-held spinlock.
    Sleeping invocations (lock released):
      - NCR5380_transfer_pio() -> NCR5380_poll_politely()
      - NCR5380_poll_politely()

    Atomic invocations (lock acquired):
      - NCR5380_transfer_dma()
	-> NCR5380_dma_recv_setup()
           => generic_NCR5380_precv() -> NCR5380_poll_politely()
	   => macscsi_pread() -> NCR5380_poll_politely()

	-> NCR5380_dma_send_setup()
 	   => generic_NCR5380_psend -> NCR5380_poll_politely2()
	   => macscsi_pwrite() -> NCR5380_poll_politely()

	-> NCR5380_poll_politely2()
        -> NCR5380_dma_complete()
           -> NCR5380_transfer_pio()
	      -> NCR5380_poll_politely()
      - NCR5380_transfer_pio() -> NCR5380_poll_politely

  - NCR5380_reselect(), atomic, always called with hostdata spinlock
    held.

Since NCR5380_poll_politely2() already takes a "wait" argument in jiffies,
use it to determine if the function can sleep. Modify atomic callers, which
passed an unused wait value in terms of HZ, to pass zero.

Link: https://lore.kernel.org/r/20201206075157.19067-1-a.darwish@linutronix.de
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: <linux-m68k@lists.linux-m68k.org>
Suggested-by: Finn Thain <fthain@telegraphics.com.au>
Co-developed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2020-12-07 20:24:09 -05:00

548 lines
16 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic Macintosh NCR5380 driver
*
* Copyright 1998, Michael Schmitz <mschmitz@lbl.gov>
*
* Copyright 2019 Finn Thain
*
* derived in part from:
*/
/*
* Generic Generic NCR5380 driver
*
* Copyright 1995, Russell King
*/
#include <linux/delay.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <asm/hwtest.h>
#include <asm/io.h>
#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/setup.h>
#include <scsi/scsi_host.h>
/* Definitions for the core NCR5380 driver. */
#define NCR5380_implementation_fields int pdma_residual
#define NCR5380_read(reg) in_8(hostdata->io + ((reg) << 4))
#define NCR5380_write(reg, value) out_8(hostdata->io + ((reg) << 4), value)
#define NCR5380_dma_xfer_len macscsi_dma_xfer_len
#define NCR5380_dma_recv_setup macscsi_pread
#define NCR5380_dma_send_setup macscsi_pwrite
#define NCR5380_dma_residual macscsi_dma_residual
#define NCR5380_intr macscsi_intr
#define NCR5380_queue_command macscsi_queue_command
#define NCR5380_abort macscsi_abort
#define NCR5380_host_reset macscsi_host_reset
#define NCR5380_info macscsi_info
#include "NCR5380.h"
static int setup_can_queue = -1;
module_param(setup_can_queue, int, 0);
static int setup_cmd_per_lun = -1;
module_param(setup_cmd_per_lun, int, 0);
static int setup_sg_tablesize = -1;
module_param(setup_sg_tablesize, int, 0);
static int setup_use_pdma = 512;
module_param(setup_use_pdma, int, 0);
static int setup_hostid = -1;
module_param(setup_hostid, int, 0);
static int setup_toshiba_delay = -1;
module_param(setup_toshiba_delay, int, 0);
#ifndef MODULE
static int __init mac_scsi_setup(char *str)
{
int ints[8];
(void)get_options(str, ARRAY_SIZE(ints), ints);
if (ints[0] < 1) {
pr_err("Usage: mac5380=<can_queue>[,<cmd_per_lun>[,<sg_tablesize>[,<hostid>[,<use_tags>[,<use_pdma>[,<toshiba_delay>]]]]]]\n");
return 0;
}
if (ints[0] >= 1)
setup_can_queue = ints[1];
if (ints[0] >= 2)
setup_cmd_per_lun = ints[2];
if (ints[0] >= 3)
setup_sg_tablesize = ints[3];
if (ints[0] >= 4)
setup_hostid = ints[4];
/* ints[5] (use_tagged_queuing) is ignored */
if (ints[0] >= 6)
setup_use_pdma = ints[6];
if (ints[0] >= 7)
setup_toshiba_delay = ints[7];
return 1;
}
__setup("mac5380=", mac_scsi_setup);
#endif /* !MODULE */
/*
* According to "Inside Macintosh: Devices", Mac OS requires disk drivers to
* specify the number of bytes between the delays expected from a SCSI target.
* This allows the operating system to "prevent bus errors when a target fails
* to deliver the next byte within the processor bus error timeout period."
* Linux SCSI drivers lack knowledge of the timing behaviour of SCSI targets
* so bus errors are unavoidable.
*
* If a MOVE.B instruction faults, we assume that zero bytes were transferred
* and simply retry. That assumption probably depends on target behaviour but
* seems to hold up okay. The NOP provides synchronization: without it the
* fault can sometimes occur after the program counter has moved past the
* offending instruction. Post-increment addressing can't be used.
*/
#define MOVE_BYTE(operands) \
asm volatile ( \
"1: moveb " operands " \n" \
"11: nop \n" \
" addq #1,%0 \n" \
" subq #1,%1 \n" \
"40: \n" \
" \n" \
".section .fixup,\"ax\" \n" \
".even \n" \
"90: movel #1, %2 \n" \
" jra 40b \n" \
".previous \n" \
" \n" \
".section __ex_table,\"a\" \n" \
".align 4 \n" \
".long 1b,90b \n" \
".long 11b,90b \n" \
".previous \n" \
: "+a" (addr), "+r" (n), "+r" (result) : "a" (io))
/*
* If a MOVE.W (or MOVE.L) instruction faults, it cannot be retried because
* the residual byte count would be uncertain. In that situation the MOVE_WORD
* macro clears n in the fixup section to abort the transfer.
*/
#define MOVE_WORD(operands) \
asm volatile ( \
"1: movew " operands " \n" \
"11: nop \n" \
" subq #2,%1 \n" \
"40: \n" \
" \n" \
".section .fixup,\"ax\" \n" \
".even \n" \
"90: movel #0, %1 \n" \
" movel #2, %2 \n" \
" jra 40b \n" \
".previous \n" \
" \n" \
".section __ex_table,\"a\" \n" \
".align 4 \n" \
".long 1b,90b \n" \
".long 11b,90b \n" \
".previous \n" \
: "+a" (addr), "+r" (n), "+r" (result) : "a" (io))
#define MOVE_16_WORDS(operands) \
asm volatile ( \
"1: movew " operands " \n" \
"2: movew " operands " \n" \
"3: movew " operands " \n" \
"4: movew " operands " \n" \
"5: movew " operands " \n" \
"6: movew " operands " \n" \
"7: movew " operands " \n" \
"8: movew " operands " \n" \
"9: movew " operands " \n" \
"10: movew " operands " \n" \
"11: movew " operands " \n" \
"12: movew " operands " \n" \
"13: movew " operands " \n" \
"14: movew " operands " \n" \
"15: movew " operands " \n" \
"16: movew " operands " \n" \
"17: nop \n" \
" subl #32,%1 \n" \
"40: \n" \
" \n" \
".section .fixup,\"ax\" \n" \
".even \n" \
"90: movel #0, %1 \n" \
" movel #2, %2 \n" \
" jra 40b \n" \
".previous \n" \
" \n" \
".section __ex_table,\"a\" \n" \
".align 4 \n" \
".long 1b,90b \n" \
".long 2b,90b \n" \
".long 3b,90b \n" \
".long 4b,90b \n" \
".long 5b,90b \n" \
".long 6b,90b \n" \
".long 7b,90b \n" \
".long 8b,90b \n" \
".long 9b,90b \n" \
".long 10b,90b \n" \
".long 11b,90b \n" \
".long 12b,90b \n" \
".long 13b,90b \n" \
".long 14b,90b \n" \
".long 15b,90b \n" \
".long 16b,90b \n" \
".long 17b,90b \n" \
".previous \n" \
: "+a" (addr), "+r" (n), "+r" (result) : "a" (io))
#define MAC_PDMA_DELAY 32
static inline int mac_pdma_recv(void __iomem *io, unsigned char *start, int n)
{
unsigned char *addr = start;
int result = 0;
if (n >= 1) {
MOVE_BYTE("%3@,%0@");
if (result)
goto out;
}
if (n >= 1 && ((unsigned long)addr & 1)) {
MOVE_BYTE("%3@,%0@");
if (result)
goto out;
}
while (n >= 32)
MOVE_16_WORDS("%3@,%0@+");
while (n >= 2)
MOVE_WORD("%3@,%0@+");
if (result)
return start - addr; /* Negated to indicate uncertain length */
if (n == 1)
MOVE_BYTE("%3@,%0@");
out:
return addr - start;
}
static inline int mac_pdma_send(unsigned char *start, void __iomem *io, int n)
{
unsigned char *addr = start;
int result = 0;
if (n >= 1) {
MOVE_BYTE("%0@,%3@");
if (result)
goto out;
}
if (n >= 1 && ((unsigned long)addr & 1)) {
MOVE_BYTE("%0@,%3@");
if (result)
goto out;
}
while (n >= 32)
MOVE_16_WORDS("%0@+,%3@");
while (n >= 2)
MOVE_WORD("%0@+,%3@");
if (result)
return start - addr; /* Negated to indicate uncertain length */
if (n == 1)
MOVE_BYTE("%0@,%3@");
out:
return addr - start;
}
/* The "SCSI DMA" chip on the IIfx implements this register. */
#define CTRL_REG 0x8
#define CTRL_INTERRUPTS_ENABLE BIT(1)
#define CTRL_HANDSHAKE_MODE BIT(3)
static inline void write_ctrl_reg(struct NCR5380_hostdata *hostdata, u32 value)
{
out_be32(hostdata->io + (CTRL_REG << 4), value);
}
static inline int macscsi_pread(struct NCR5380_hostdata *hostdata,
unsigned char *dst, int len)
{
u8 __iomem *s = hostdata->pdma_io + (INPUT_DATA_REG << 4);
unsigned char *d = dst;
int result = 0;
hostdata->pdma_residual = len;
while (!NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
BASR_DRQ | BASR_PHASE_MATCH,
BASR_DRQ | BASR_PHASE_MATCH, 0)) {
int bytes;
if (macintosh_config->ident == MAC_MODEL_IIFX)
write_ctrl_reg(hostdata, CTRL_HANDSHAKE_MODE |
CTRL_INTERRUPTS_ENABLE);
bytes = mac_pdma_recv(s, d, min(hostdata->pdma_residual, 512));
if (bytes > 0) {
d += bytes;
hostdata->pdma_residual -= bytes;
}
if (hostdata->pdma_residual == 0)
goto out;
if (NCR5380_poll_politely2(hostdata, STATUS_REG, SR_REQ, SR_REQ,
BUS_AND_STATUS_REG, BASR_ACK,
BASR_ACK, 0) < 0)
scmd_printk(KERN_DEBUG, hostdata->connected,
"%s: !REQ and !ACK\n", __func__);
if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH))
goto out;
if (bytes == 0)
udelay(MAC_PDMA_DELAY);
if (bytes >= 0)
continue;
dsprintk(NDEBUG_PSEUDO_DMA, hostdata->host,
"%s: bus error (%d/%d)\n", __func__, d - dst, len);
NCR5380_dprint(NDEBUG_PSEUDO_DMA, hostdata->host);
result = -1;
goto out;
}
scmd_printk(KERN_ERR, hostdata->connected,
"%s: phase mismatch or !DRQ\n", __func__);
NCR5380_dprint(NDEBUG_PSEUDO_DMA, hostdata->host);
result = -1;
out:
if (macintosh_config->ident == MAC_MODEL_IIFX)
write_ctrl_reg(hostdata, CTRL_INTERRUPTS_ENABLE);
return result;
}
static inline int macscsi_pwrite(struct NCR5380_hostdata *hostdata,
unsigned char *src, int len)
{
unsigned char *s = src;
u8 __iomem *d = hostdata->pdma_io + (OUTPUT_DATA_REG << 4);
int result = 0;
hostdata->pdma_residual = len;
while (!NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
BASR_DRQ | BASR_PHASE_MATCH,
BASR_DRQ | BASR_PHASE_MATCH, 0)) {
int bytes;
if (macintosh_config->ident == MAC_MODEL_IIFX)
write_ctrl_reg(hostdata, CTRL_HANDSHAKE_MODE |
CTRL_INTERRUPTS_ENABLE);
bytes = mac_pdma_send(s, d, min(hostdata->pdma_residual, 512));
if (bytes > 0) {
s += bytes;
hostdata->pdma_residual -= bytes;
}
if (hostdata->pdma_residual == 0) {
if (NCR5380_poll_politely(hostdata, TARGET_COMMAND_REG,
TCR_LAST_BYTE_SENT,
TCR_LAST_BYTE_SENT,
0) < 0) {
scmd_printk(KERN_ERR, hostdata->connected,
"%s: Last Byte Sent timeout\n", __func__);
result = -1;
}
goto out;
}
if (NCR5380_poll_politely2(hostdata, STATUS_REG, SR_REQ, SR_REQ,
BUS_AND_STATUS_REG, BASR_ACK,
BASR_ACK, 0) < 0)
scmd_printk(KERN_DEBUG, hostdata->connected,
"%s: !REQ and !ACK\n", __func__);
if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH))
goto out;
if (bytes == 0)
udelay(MAC_PDMA_DELAY);
if (bytes >= 0)
continue;
dsprintk(NDEBUG_PSEUDO_DMA, hostdata->host,
"%s: bus error (%d/%d)\n", __func__, s - src, len);
NCR5380_dprint(NDEBUG_PSEUDO_DMA, hostdata->host);
result = -1;
goto out;
}
scmd_printk(KERN_ERR, hostdata->connected,
"%s: phase mismatch or !DRQ\n", __func__);
NCR5380_dprint(NDEBUG_PSEUDO_DMA, hostdata->host);
result = -1;
out:
if (macintosh_config->ident == MAC_MODEL_IIFX)
write_ctrl_reg(hostdata, CTRL_INTERRUPTS_ENABLE);
return result;
}
static int macscsi_dma_xfer_len(struct NCR5380_hostdata *hostdata,
struct scsi_cmnd *cmd)
{
if (hostdata->flags & FLAG_NO_PSEUDO_DMA ||
cmd->SCp.this_residual < setup_use_pdma)
return 0;
return cmd->SCp.this_residual;
}
static int macscsi_dma_residual(struct NCR5380_hostdata *hostdata)
{
return hostdata->pdma_residual;
}
#include "NCR5380.c"
#define DRV_MODULE_NAME "mac_scsi"
#define PFX DRV_MODULE_NAME ": "
static struct scsi_host_template mac_scsi_template = {
.module = THIS_MODULE,
.proc_name = DRV_MODULE_NAME,
.name = "Macintosh NCR5380 SCSI",
.info = macscsi_info,
.queuecommand = macscsi_queue_command,
.eh_abort_handler = macscsi_abort,
.eh_host_reset_handler = macscsi_host_reset,
.can_queue = 16,
.this_id = 7,
.sg_tablesize = 1,
.cmd_per_lun = 2,
.dma_boundary = PAGE_SIZE - 1,
.cmd_size = NCR5380_CMD_SIZE,
.max_sectors = 128,
};
static int __init mac_scsi_probe(struct platform_device *pdev)
{
struct Scsi_Host *instance;
struct NCR5380_hostdata *hostdata;
int error;
int host_flags = 0;
struct resource *irq, *pio_mem, *pdma_mem = NULL;
pio_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!pio_mem)
return -ENODEV;
pdma_mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!hwreg_present((unsigned char *)pio_mem->start +
(STATUS_REG << 4))) {
pr_info(PFX "no device detected at %pap\n", &pio_mem->start);
return -ENODEV;
}
if (setup_can_queue > 0)
mac_scsi_template.can_queue = setup_can_queue;
if (setup_cmd_per_lun > 0)
mac_scsi_template.cmd_per_lun = setup_cmd_per_lun;
if (setup_sg_tablesize > 0)
mac_scsi_template.sg_tablesize = setup_sg_tablesize;
if (setup_hostid >= 0)
mac_scsi_template.this_id = setup_hostid & 7;
instance = scsi_host_alloc(&mac_scsi_template,
sizeof(struct NCR5380_hostdata));
if (!instance)
return -ENOMEM;
if (irq)
instance->irq = irq->start;
else
instance->irq = NO_IRQ;
hostdata = shost_priv(instance);
hostdata->base = pio_mem->start;
hostdata->io = (u8 __iomem *)pio_mem->start;
if (pdma_mem && setup_use_pdma)
hostdata->pdma_io = (u8 __iomem *)pdma_mem->start;
else
host_flags |= FLAG_NO_PSEUDO_DMA;
host_flags |= setup_toshiba_delay > 0 ? FLAG_TOSHIBA_DELAY : 0;
error = NCR5380_init(instance, host_flags | FLAG_LATE_DMA_SETUP);
if (error)
goto fail_init;
if (instance->irq != NO_IRQ) {
error = request_irq(instance->irq, macscsi_intr, IRQF_SHARED,
"NCR5380", instance);
if (error)
goto fail_irq;
}
NCR5380_maybe_reset_bus(instance);
error = scsi_add_host(instance, NULL);
if (error)
goto fail_host;
platform_set_drvdata(pdev, instance);
scsi_scan_host(instance);
return 0;
fail_host:
if (instance->irq != NO_IRQ)
free_irq(instance->irq, instance);
fail_irq:
NCR5380_exit(instance);
fail_init:
scsi_host_put(instance);
return error;
}
static int __exit mac_scsi_remove(struct platform_device *pdev)
{
struct Scsi_Host *instance = platform_get_drvdata(pdev);
scsi_remove_host(instance);
if (instance->irq != NO_IRQ)
free_irq(instance->irq, instance);
NCR5380_exit(instance);
scsi_host_put(instance);
return 0;
}
static struct platform_driver mac_scsi_driver = {
.remove = __exit_p(mac_scsi_remove),
.driver = {
.name = DRV_MODULE_NAME,
},
};
module_platform_driver_probe(mac_scsi_driver, mac_scsi_probe);
MODULE_ALIAS("platform:" DRV_MODULE_NAME);
MODULE_LICENSE("GPL");
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