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linux-next/drivers/scsi/NCR5380.h
Finn Thain 08348b1c9b scsi: ncr5380: Improve interrupt latency during PIO tranfers 
Large PIO transfers are broken up into chunks to try to avoid disabling
local IRQs for long periods. But IRQs are still disabled for too long
and this causes SCC FIFO overruns during serial port transfers.

This patch reduces the PIO chunk size to reduce interrupt latency to
something on the order of milliseconds, at the expense of additional CPU
overhead from extra iterations of the NCR5380_main() loop.

That CPU overhead is a problem for slow machines (e.g. mac_scsi on 25
MHz 68030) but these machines generally use PDMA not PIO. This patch
doesn't make the overhead any worse on my Mac LC III (because it only
gets about 510 accesses per ms).

This patch decreases disk performance by a fraction of one percent for
dmx3191d on my 333 MHz PowerPC 750. Other affected hardware (such as
g_NCR5380 on x86) was not tested but 5380 ISA cards generally use PDMA
and not PIO.

[mkp: fix whitespace]

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-09-14 14:11:12 -04:00

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/*
* NCR 5380 defines
*
* Copyright 1993, Drew Eckhardt
* Visionary Computing
* (Unix consulting and custom programming)
* drew@colorado.edu
* +1 (303) 666-5836
*
* For more information, please consult
*
* NCR 5380 Family
* SCSI Protocol Controller
* Databook
* NCR Microelectronics
* 1635 Aeroplaza Drive
* Colorado Springs, CO 80916
* 1+ (719) 578-3400
* 1+ (800) 334-5454
*/
#ifndef NCR5380_H
#define NCR5380_H
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/workqueue.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_transport_spi.h>
#define NDEBUG_ARBITRATION 0x1
#define NDEBUG_AUTOSENSE 0x2
#define NDEBUG_DMA 0x4
#define NDEBUG_HANDSHAKE 0x8
#define NDEBUG_INFORMATION 0x10
#define NDEBUG_INIT 0x20
#define NDEBUG_INTR 0x40
#define NDEBUG_LINKED 0x80
#define NDEBUG_MAIN 0x100
#define NDEBUG_NO_DATAOUT 0x200
#define NDEBUG_NO_WRITE 0x400
#define NDEBUG_PIO 0x800
#define NDEBUG_PSEUDO_DMA 0x1000
#define NDEBUG_QUEUES 0x2000
#define NDEBUG_RESELECTION 0x4000
#define NDEBUG_SELECTION 0x8000
#define NDEBUG_USLEEP 0x10000
#define NDEBUG_LAST_BYTE_SENT 0x20000
#define NDEBUG_RESTART_SELECT 0x40000
#define NDEBUG_EXTENDED 0x80000
#define NDEBUG_C400_PREAD 0x100000
#define NDEBUG_C400_PWRITE 0x200000
#define NDEBUG_LISTS 0x400000
#define NDEBUG_ABORT 0x800000
#define NDEBUG_TAGS 0x1000000
#define NDEBUG_MERGING 0x2000000
#define NDEBUG_ANY 0xFFFFFFFFUL
/*
* The contents of the OUTPUT DATA register are asserted on the bus when
* either arbitration is occurring or the phase-indicating signals (
* IO, CD, MSG) in the TARGET COMMAND register and the ASSERT DATA
* bit in the INITIATOR COMMAND register is set.
*/
#define OUTPUT_DATA_REG 0 /* wo DATA lines on SCSI bus */
#define CURRENT_SCSI_DATA_REG 0 /* ro same */
#define INITIATOR_COMMAND_REG 1 /* rw */
#define ICR_ASSERT_RST 0x80 /* rw Set to assert RST */
#define ICR_ARBITRATION_PROGRESS 0x40 /* ro Indicates arbitration complete */
#define ICR_TRI_STATE 0x40 /* wo Set to tri-state drivers */
#define ICR_ARBITRATION_LOST 0x20 /* ro Indicates arbitration lost */
#define ICR_DIFF_ENABLE 0x20 /* wo Set to enable diff. drivers */
#define ICR_ASSERT_ACK 0x10 /* rw ini Set to assert ACK */
#define ICR_ASSERT_BSY 0x08 /* rw Set to assert BSY */
#define ICR_ASSERT_SEL 0x04 /* rw Set to assert SEL */
#define ICR_ASSERT_ATN 0x02 /* rw Set to assert ATN */
#define ICR_ASSERT_DATA 0x01 /* rw SCSI_DATA_REG is asserted */
#ifdef DIFFERENTIAL
#define ICR_BASE ICR_DIFF_ENABLE
#else
#define ICR_BASE 0
#endif
#define MODE_REG 2
/*
* Note : BLOCK_DMA code will keep DRQ asserted for the duration of the
* transfer, causing the chip to hog the bus. You probably don't want
* this.
*/
#define MR_BLOCK_DMA_MODE 0x80 /* rw block mode DMA */
#define MR_TARGET 0x40 /* rw target mode */
#define MR_ENABLE_PAR_CHECK 0x20 /* rw enable parity checking */
#define MR_ENABLE_PAR_INTR 0x10 /* rw enable bad parity interrupt */
#define MR_ENABLE_EOP_INTR 0x08 /* rw enable eop interrupt */
#define MR_MONITOR_BSY 0x04 /* rw enable int on unexpected bsy fail */
#define MR_DMA_MODE 0x02 /* rw DMA / pseudo DMA mode */
#define MR_ARBITRATE 0x01 /* rw start arbitration */
#ifdef PARITY
#define MR_BASE MR_ENABLE_PAR_CHECK
#else
#define MR_BASE 0
#endif
#define TARGET_COMMAND_REG 3
#define TCR_LAST_BYTE_SENT 0x80 /* ro DMA done */
#define TCR_ASSERT_REQ 0x08 /* tgt rw assert REQ */
#define TCR_ASSERT_MSG 0x04 /* tgt rw assert MSG */
#define TCR_ASSERT_CD 0x02 /* tgt rw assert CD */
#define TCR_ASSERT_IO 0x01 /* tgt rw assert IO */
#define STATUS_REG 4 /* ro */
/*
* Note : a set bit indicates an active signal, driven by us or another
* device.
*/
#define SR_RST 0x80
#define SR_BSY 0x40
#define SR_REQ 0x20
#define SR_MSG 0x10
#define SR_CD 0x08
#define SR_IO 0x04
#define SR_SEL 0x02
#define SR_DBP 0x01
/*
* Setting a bit in this register will cause an interrupt to be generated when
* BSY is false and SEL true and this bit is asserted on the bus.
*/
#define SELECT_ENABLE_REG 4 /* wo */
#define BUS_AND_STATUS_REG 5 /* ro */
#define BASR_END_DMA_TRANSFER 0x80 /* ro set on end of transfer */
#define BASR_DRQ 0x40 /* ro mirror of DRQ pin */
#define BASR_PARITY_ERROR 0x20 /* ro parity error detected */
#define BASR_IRQ 0x10 /* ro mirror of IRQ pin */
#define BASR_PHASE_MATCH 0x08 /* ro Set when MSG CD IO match TCR */
#define BASR_BUSY_ERROR 0x04 /* ro Unexpected change to inactive state */
#define BASR_ATN 0x02 /* ro BUS status */
#define BASR_ACK 0x01 /* ro BUS status */
/* Write any value to this register to start a DMA send */
#define START_DMA_SEND_REG 5 /* wo */
/*
* Used in DMA transfer mode, data is latched from the SCSI bus on
* the falling edge of REQ (ini) or ACK (tgt)
*/
#define INPUT_DATA_REG 6 /* ro */
/* Write any value to this register to start a DMA receive */
#define START_DMA_TARGET_RECEIVE_REG 6 /* wo */
/* Read this register to clear interrupt conditions */
#define RESET_PARITY_INTERRUPT_REG 7 /* ro */
/* Write any value to this register to start an ini mode DMA receive */
#define START_DMA_INITIATOR_RECEIVE_REG 7 /* wo */
/* NCR 53C400(A) Control Status Register bits: */
#define CSR_RESET 0x80 /* wo Resets 53c400 */
#define CSR_53C80_REG 0x80 /* ro 5380 registers busy */
#define CSR_TRANS_DIR 0x40 /* rw Data transfer direction */
#define CSR_SCSI_BUFF_INTR 0x20 /* rw Enable int on transfer ready */
#define CSR_53C80_INTR 0x10 /* rw Enable 53c80 interrupts */
#define CSR_SHARED_INTR 0x08 /* rw Interrupt sharing */
#define CSR_HOST_BUF_NOT_RDY 0x04 /* ro Is Host buffer ready */
#define CSR_SCSI_BUF_RDY 0x02 /* ro SCSI buffer read */
#define CSR_GATED_53C80_IRQ 0x01 /* ro Last block xferred */
#if 0
#define CSR_BASE CSR_SCSI_BUFF_INTR | CSR_53C80_INTR
#else
#define CSR_BASE CSR_53C80_INTR
#endif
/* Note : PHASE_* macros are based on the values of the STATUS register */
#define PHASE_MASK (SR_MSG | SR_CD | SR_IO)
#define PHASE_DATAOUT 0
#define PHASE_DATAIN SR_IO
#define PHASE_CMDOUT SR_CD
#define PHASE_STATIN (SR_CD | SR_IO)
#define PHASE_MSGOUT (SR_MSG | SR_CD)
#define PHASE_MSGIN (SR_MSG | SR_CD | SR_IO)
#define PHASE_UNKNOWN 0xff
/*
* Convert status register phase to something we can use to set phase in
* the target register so we can get phase mismatch interrupts on DMA
* transfers.
*/
#define PHASE_SR_TO_TCR(phase) ((phase) >> 2)
/*
* These are "special" values for the irq and dma_channel fields of the
* Scsi_Host structure
*/
#define DMA_NONE 255
#define IRQ_AUTO 254
#define DMA_AUTO 254
#define PORT_AUTO 0xffff /* autoprobe io port for 53c400a */
#ifndef NO_IRQ
#define NO_IRQ 0
#endif
#define FLAG_DMA_FIXUP 1 /* Use DMA errata workarounds */
#define FLAG_NO_PSEUDO_DMA 8 /* Inhibit DMA */
#define FLAG_LATE_DMA_SETUP 32 /* Setup NCR before DMA H/W */
#define FLAG_TOSHIBA_DELAY 128 /* Allow for borken CD-ROMs */
struct NCR5380_hostdata {
NCR5380_implementation_fields; /* implementation specific */
struct Scsi_Host *host; /* Host backpointer */
unsigned char id_mask, id_higher_mask; /* 1 << id, all bits greater */
unsigned char busy[8]; /* index = target, bit = lun */
int dma_len; /* requested length of DMA */
unsigned char last_message; /* last message OUT */
struct scsi_cmnd *connected; /* currently connected cmnd */
struct scsi_cmnd *selecting; /* cmnd to be connected */
struct list_head unissued; /* waiting to be issued */
struct list_head autosense; /* priority issue queue */
struct list_head disconnected; /* waiting for reconnect */
spinlock_t lock; /* protects this struct */
int flags;
struct scsi_eh_save ses;
struct scsi_cmnd *sensing;
char info[256];
int read_overruns; /* number of bytes to cut from a
* transfer to handle chip overruns */
struct work_struct main_task;
struct workqueue_struct *work_q;
unsigned long accesses_per_ms; /* chip register accesses per ms */
};
#ifdef __KERNEL__
struct NCR5380_cmd {
struct list_head list;
};
#define NCR5380_CMD_SIZE (sizeof(struct NCR5380_cmd))
#define NCR5380_PIO_CHUNK_SIZE 256
static inline struct scsi_cmnd *NCR5380_to_scmd(struct NCR5380_cmd *ncmd_ptr)
{
return ((struct scsi_cmnd *)ncmd_ptr) - 1;
}
#ifndef NDEBUG
#define NDEBUG (0)
#endif
#define dprintk(flg, fmt, ...) \
do { if ((NDEBUG) & (flg)) \
printk(KERN_DEBUG fmt, ## __VA_ARGS__); } while (0)
#define dsprintk(flg, host, fmt, ...) \
do { if ((NDEBUG) & (flg)) \
shost_printk(KERN_DEBUG, host, fmt, ## __VA_ARGS__); \
} while (0)
#if NDEBUG
#define NCR5380_dprint(flg, arg) \
do { if ((NDEBUG) & (flg)) NCR5380_print(arg); } while (0)
#define NCR5380_dprint_phase(flg, arg) \
do { if ((NDEBUG) & (flg)) NCR5380_print_phase(arg); } while (0)
static void NCR5380_print_phase(struct Scsi_Host *instance);
static void NCR5380_print(struct Scsi_Host *instance);
#else
#define NCR5380_dprint(flg, arg) do {} while (0)
#define NCR5380_dprint_phase(flg, arg) do {} while (0)
#endif
static int NCR5380_probe_irq(struct Scsi_Host *instance, int possible);
static int NCR5380_init(struct Scsi_Host *instance, int flags);
static int NCR5380_maybe_reset_bus(struct Scsi_Host *);
static void NCR5380_exit(struct Scsi_Host *instance);
static void NCR5380_information_transfer(struct Scsi_Host *instance);
static irqreturn_t NCR5380_intr(int irq, void *dev_id);
static void NCR5380_main(struct work_struct *work);
static const char *NCR5380_info(struct Scsi_Host *instance);
static void NCR5380_reselect(struct Scsi_Host *instance);
static struct scsi_cmnd *NCR5380_select(struct Scsi_Host *, struct scsi_cmnd *);
static int NCR5380_transfer_dma(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data);
static int NCR5380_transfer_pio(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data);
static int NCR5380_poll_politely2(struct Scsi_Host *, int, int, int, int, int, int, int);
static inline int NCR5380_poll_politely(struct Scsi_Host *instance,
int reg, int bit, int val, int wait)
{
return NCR5380_poll_politely2(instance, reg, bit, val,
reg, bit, val, wait);
}
#endif /* __KERNEL__ */
#endif /* NCR5380_H */
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