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Commit 3a0f64bf authored by Finn Thain's avatar Finn Thain Committed by Martin K. Petersen
Browse files

mac_scsi: Fix pseudo DMA implementation 



Fix various issues: Comments about bus errors are incorrect. The
PDMA asm must return the size of the memory access that faulted so the
transfer count can be adjusted accordingly. A phase change may cause a
bus error but should not be treated as failure. A bus error does not
always imply a phase change and generally the transfer may continue.
Scatter/gather doesn't seem to work with PDMA due to overruns. This is
a pity because peak throughput seems to double with SG_ALL.
Tested on a Mac LC III and a PowerBook 520.

Signed-off-by: default avatarFinn Thain <fthain@telegraphics.com.au>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent ded155b5

drivers/scsi/NCR5380.h

+2 −0
Original line number Diff line number Diff line
@@ -292,6 +292,8 @@ 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_politely(struct Scsi_Host *, int, int, int, int);

static int NCR5380_poll_politely2(struct Scsi_Host *, int, int, int, int, int, int, int);



#endif				/* __KERNEL__ */

#endif				/* NCR5380_H */

drivers/scsi/mac_scsi.c

+117 −95
Original line number Diff line number Diff line
@@ -28,7 +28,8 @@ 


/* Definitions for the core NCR5380 driver. */



#define NCR5380_implementation_fields   unsigned char *pdma_base

#define NCR5380_implementation_fields   unsigned char *pdma_base; \

                                        int pdma_residual



#define NCR5380_read(reg)               macscsi_read(instance, reg)

#define NCR5380_write(reg, value)       macscsi_write(instance, reg, value)
@@ -37,7 +38,7 @@ 
        macscsi_dma_xfer_len(instance, cmd)

#define NCR5380_dma_recv_setup          macscsi_pread

#define NCR5380_dma_send_setup          macscsi_pwrite

#define NCR5380_dma_residual(instance)  (0)

#define NCR5380_dma_residual(instance)  (hostdata->pdma_residual)



#define NCR5380_intr                    macscsi_intr

#define NCR5380_queue_command           macscsi_queue_command
@@ -104,18 +105,9 @@ static int __init mac_scsi_setup(char *str) 
__setup("mac5380=", mac_scsi_setup);

#endif /* !MODULE */



/* 

   Pseudo-DMA: (Ove Edlund)

   The code attempts to catch bus errors that occur if one for example

   "trips over the cable".

   XXX: Since bus errors in the PDMA routines never happen on my 

   computer, the bus error code is untested. 

   If the code works as intended, a bus error results in Pseudo-DMA 

   being disabled, meaning that the driver switches to slow handshake.

   If bus errors are NOT extremely rare, this has to be changed. 

*/

/* Pseudo DMA asm originally by Ove Edlund */



#define CP_IO_TO_MEM(s,d,len)				\

#define CP_IO_TO_MEM(s,d,n)				\

__asm__ __volatile__					\

    ("    cmp.w  #4,%2\n"				\

     "    bls    8f\n"					\
@@ -152,61 +144,73 @@ __asm__ __volatile__ \ 
     " 9: \n"						\

     ".section .fixup,\"ax\"\n"				\

     "    .even\n"					\

     "90: moveq.l #1, %2\n"				\

     "91: moveq.l #1, %2\n"				\

     "    jra 9b\n"					\

     "94: moveq.l #4, %2\n"				\

     "    jra 9b\n"					\

     ".previous\n"					\

     ".section __ex_table,\"a\"\n"			\

     "   .align 4\n"					\

     "   .long  1b,90b\n"				\

     "   .long  3b,90b\n"				\

     "   .long 31b,90b\n"				\

     "   .long 32b,90b\n"				\

     "   .long 33b,90b\n"				\

     "   .long 34b,90b\n"				\

     "   .long 35b,90b\n"				\

     "   .long 36b,90b\n"				\

     "   .long 37b,90b\n"				\

     "   .long  5b,90b\n"				\

     "   .long  7b,90b\n"				\

     "   .long  1b,91b\n"				\

     "   .long  3b,94b\n"				\

     "   .long 31b,94b\n"				\

     "   .long 32b,94b\n"				\

     "   .long 33b,94b\n"				\

     "   .long 34b,94b\n"				\

     "   .long 35b,94b\n"				\

     "   .long 36b,94b\n"				\

     "   .long 37b,94b\n"				\

     "   .long  5b,94b\n"				\

     "   .long  7b,91b\n"				\

     ".previous"					\

     : "=a"(s), "=a"(d), "=d"(len)			\

     : "0"(s), "1"(d), "2"(len)				\

     : "=a"(s), "=a"(d), "=d"(n)			\

     : "0"(s), "1"(d), "2"(n)				\

     : "d0")



static int macscsi_pread(struct Scsi_Host *instance,

                         unsigned char *dst, int len)

{

	struct NCR5380_hostdata *hostdata = shost_priv(instance);

	unsigned char *d;

	unsigned char *s;

	unsigned char *s = hostdata->pdma_base + (INPUT_DATA_REG << 4);

	unsigned char *d = dst;

	int n = len;

	int transferred;



	s = hostdata->pdma_base + (INPUT_DATA_REG << 4);

	d = dst;

	while (!NCR5380_poll_politely(instance, BUS_AND_STATUS_REG,

	                              BASR_DRQ | BASR_PHASE_MATCH,

	                              BASR_DRQ | BASR_PHASE_MATCH, HZ / 64)) {

		CP_IO_TO_MEM(s, d, n);



	/* These conditions are derived from MacOS */

		transferred = d - dst - n;

		hostdata->pdma_residual = len - transferred;



	while (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ) &&

	       !(NCR5380_read(STATUS_REG) & SR_REQ))

		;



	if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ) &&

	    (NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH)) {

		pr_err("Error in macscsi_pread\n");

		return -1;

	}

		/* No bus error. */

		if (n == 0)

			return 0;



	CP_IO_TO_MEM(s, d, len);

		/* Target changed phase early? */

		if (NCR5380_poll_politely2(instance, STATUS_REG, SR_REQ, SR_REQ,

		                           BUS_AND_STATUS_REG, BASR_ACK, BASR_ACK, HZ / 64) < 0)

			scmd_printk(KERN_ERR, hostdata->connected,

			            "%s: !REQ and !ACK\n", __func__);

		if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH))

			return 0;



	if (len != 0) {

		pr_notice("Bus error in macscsi_pread\n");

		return -1;

		dsprintk(NDEBUG_PSEUDO_DMA, instance,

		         "%s: bus error (%d/%d)\n", __func__, transferred, len);

		NCR5380_dprint(NDEBUG_PSEUDO_DMA, instance);

		d = dst + transferred;

		n = len - transferred;

	}



	return 0;

	scmd_printk(KERN_ERR, hostdata->connected,

	            "%s: phase mismatch or !DRQ\n", __func__);

	NCR5380_dprint(NDEBUG_PSEUDO_DMA, instance);

	return -1;

}





#define CP_MEM_TO_IO(s,d,len)				\

#define CP_MEM_TO_IO(s,d,n)				\

__asm__ __volatile__					\

    ("    cmp.w  #4,%2\n"				\

     "    bls    8f\n"					\
@@ -243,68 +247,88 @@ __asm__ __volatile__ \ 
     " 9: \n"						\

     ".section .fixup,\"ax\"\n"				\

     "    .even\n"					\

     "90: moveq.l #1, %2\n"				\

     "91: moveq.l #1, %2\n"				\

     "    jra 9b\n"					\

     "94: moveq.l #4, %2\n"				\

     "    jra 9b\n"					\

     ".previous\n"					\

     ".section __ex_table,\"a\"\n"			\

     "   .align 4\n"					\

     "   .long  1b,90b\n"				\

     "   .long  3b,90b\n"				\

     "   .long 31b,90b\n"				\

     "   .long 32b,90b\n"				\

     "   .long 33b,90b\n"				\

     "   .long 34b,90b\n"				\

     "   .long 35b,90b\n"				\

     "   .long 36b,90b\n"				\

     "   .long 37b,90b\n"				\

     "   .long  5b,90b\n"				\

     "   .long  7b,90b\n"				\

     "   .long  1b,91b\n"				\

     "   .long  3b,94b\n"				\

     "   .long 31b,94b\n"				\

     "   .long 32b,94b\n"				\

     "   .long 33b,94b\n"				\

     "   .long 34b,94b\n"				\

     "   .long 35b,94b\n"				\

     "   .long 36b,94b\n"				\

     "   .long 37b,94b\n"				\

     "   .long  5b,94b\n"				\

     "   .long  7b,91b\n"				\

     ".previous"					\

     : "=a"(s), "=a"(d), "=d"(len)			\

     : "0"(s), "1"(d), "2"(len)				\

     : "=a"(s), "=a"(d), "=d"(n)			\

     : "0"(s), "1"(d), "2"(n)				\

     : "d0")



static int macscsi_pwrite(struct Scsi_Host *instance,

                          unsigned char *src, int len)

{

	struct NCR5380_hostdata *hostdata = shost_priv(instance);

	unsigned char *s;

	unsigned char *d;



	s = src;

	d = hostdata->pdma_base + (OUTPUT_DATA_REG << 4);



	/* These conditions are derived from MacOS */

	unsigned char *s = src;

	unsigned char *d = hostdata->pdma_base + (OUTPUT_DATA_REG << 4);

	int n = len;

	int transferred;



	while (!NCR5380_poll_politely(instance, BUS_AND_STATUS_REG,

	                              BASR_DRQ | BASR_PHASE_MATCH,

	                              BASR_DRQ | BASR_PHASE_MATCH, HZ / 64)) {

		CP_MEM_TO_IO(s, d, n);



		transferred = s - src - n;

		hostdata->pdma_residual = len - transferred;



		/* Target changed phase early? */

		if (NCR5380_poll_politely2(instance, STATUS_REG, SR_REQ, SR_REQ,

		                           BUS_AND_STATUS_REG, BASR_ACK, BASR_ACK, HZ / 64) < 0)

			scmd_printk(KERN_ERR, hostdata->connected,

			            "%s: !REQ and !ACK\n", __func__);

		if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH))

			return 0;



	while (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ) &&

	       (!(NCR5380_read(STATUS_REG) & SR_REQ) ||

	        (NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH)))

		;

		/* No bus error. */

		if (n == 0) {

			if (NCR5380_poll_politely(instance, TARGET_COMMAND_REG,

			                          TCR_LAST_BYTE_SENT,

			                          TCR_LAST_BYTE_SENT, HZ / 64) < 0)

				scmd_printk(KERN_ERR, hostdata->connected,

				            "%s: Last Byte Sent timeout\n", __func__);

			return 0;

		}



	if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ)) {

		pr_err("Error in macscsi_pwrite\n");

		return -1;

		dsprintk(NDEBUG_PSEUDO_DMA, instance,

		         "%s: bus error (%d/%d)\n", __func__, transferred, len);

		NCR5380_dprint(NDEBUG_PSEUDO_DMA, instance);

		s = src + transferred;

		n = len - transferred;

	}



	CP_MEM_TO_IO(s, d, len);

	scmd_printk(KERN_ERR, hostdata->connected,

	            "%s: phase mismatch or !DRQ\n", __func__);

	NCR5380_dprint(NDEBUG_PSEUDO_DMA, instance);



	if (len != 0) {

		pr_notice("Bus error in macscsi_pwrite\n");

	return -1;

}



	return 0;

}



static int macscsi_dma_xfer_len(struct Scsi_Host *instance,

                                struct scsi_cmnd *cmd)

{

	struct NCR5380_hostdata *hostdata = shost_priv(instance);



	if (hostdata->flags & FLAG_NO_PSEUDO_DMA)

	if (hostdata->flags & FLAG_NO_PSEUDO_DMA ||

	    cmd->SCp.this_residual < 16)

		return 0;



	return cmd->transfersize;

	return cmd->SCp.this_residual;

}



#include "NCR5380.c"
@@ -322,7 +346,7 @@ static struct scsi_host_template mac_scsi_template = { 
	.eh_bus_reset_handler	= macscsi_bus_reset,

	.can_queue		= 16,

	.this_id		= 7,

	.sg_tablesize		= SG_ALL,

	.sg_tablesize		= 1,

	.cmd_per_lun		= 2,

	.use_clustering		= DISABLE_CLUSTERING,

	.cmd_size		= NCR5380_CMD_SIZE,
@@ -358,8 +382,6 @@ static int __init mac_scsi_probe(struct platform_device *pdev) 
		mac_scsi_template.sg_tablesize = setup_sg_tablesize;

	if (setup_hostid >= 0)

		mac_scsi_template.this_id = setup_hostid & 7;

	if (setup_use_pdma < 0)

		setup_use_pdma = 0;



	instance = scsi_host_alloc(&mac_scsi_template,

	                           sizeof(struct NCR5380_hostdata));