Commit 68a4f84a authored by Alex Henrie's avatar Alex Henrie Committed by Martin K. Petersen
Browse files

scsi: ppa: Add a module parameter for the transfer mode 



I have an Iomega Z100P2 zip drive, but it does not work with my StarTech
PEX1P2 AX99100 PCIe parallel port, which evidently does not support 16-bit
or 32-bit EPP. Currently the only way to tell the PPA driver to use 8-bit
EPP is to write 'mode=3' to /proc/scsi/ppa/*, but the driver doesn't
actually distinguish between the three EPP modes and still tries to use
16-bit or 32-bit EPP. And even if writing to that file did make the driver
use 8-bit EPP, it still wouldn't do me any good because by the time that
file exists, the drive has already failed to initialize.

Add a new parameter /sys/module/ppa/mode to set the transfer mode before
initializing the drive. This parameter replaces the use of
CONFIG_SCSI_IZIP_EPP16 in the PPA driver.

At the same time, default to 8-bit EPP. 16-bit and 32-bit EPP are not
necessary for the drive to function, nor are they part of the IEEE 1284
standard, so the driver should not assume that they are available.

Signed-off-by: default avatarAlex Henrie <alexhenrie24@gmail.com>
Link: https://lore.kernel.org/r/20230807155856.362864-2-alexhenrie24@gmail.com


Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent b68442eb

drivers/scsi/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -836,7 +836,7 @@ config SCSI_IMM 


config SCSI_IZIP_EPP16

	bool "ppa/imm option - Use slow (but safe) EPP-16"

	depends on SCSI_PPA || SCSI_IMM

	depends on SCSI_IMM

	help

	  EPP (Enhanced Parallel Port) is a standard for parallel ports which

	  allows them to act as expansion buses that can handle up to 64

drivers/scsi/ppa.c

+42 −40
Original line number Diff line number Diff line
@@ -45,6 +45,11 @@ typedef struct { 


#include  "ppa.h"



static unsigned int mode = PPA_AUTODETECT;

module_param(mode, uint, 0644);

MODULE_PARM_DESC(mode, "Transfer mode (0 = Autodetect, 1 = SPP 4-bit, "

	"2 = SPP 8-bit, 3 = EPP 8-bit, 4 = EPP 16-bit, 5 = EPP 32-bit");



static struct scsi_pointer *ppa_scsi_pointer(struct scsi_cmnd *cmd)

{

	return scsi_cmd_priv(cmd);
@@ -157,7 +162,7 @@ static int ppa_show_info(struct seq_file *m, struct Scsi_Host *host) 
	return 0;

}



static int device_check(ppa_struct *dev);

static int device_check(ppa_struct *dev, bool autodetect);



#if PPA_DEBUG > 0

#define ppa_fail(x,y) printk("ppa: ppa_fail(%i) from %s at line %d\n",\
@@ -302,13 +307,10 @@ static int ppa_out(ppa_struct *dev, char *buffer, int len) 
	case PPA_EPP_8:

		epp_reset(ppb);

		w_ctr(ppb, 0x4);

#ifdef CONFIG_SCSI_IZIP_EPP16

		if (!(((long) buffer | len) & 0x01))

			outsw(ppb + 4, buffer, len >> 1);

#else

		if (!(((long) buffer | len) & 0x03))

		if (dev->mode == PPA_EPP_32 && !(((long) buffer | len) & 0x01))

			outsl(ppb + 4, buffer, len >> 2);

#endif

		else if (dev->mode == PPA_EPP_16 && !(((long) buffer | len) & 0x03))

			outsw(ppb + 4, buffer, len >> 1);

		else

			outsb(ppb + 4, buffer, len);

		w_ctr(ppb, 0xc);
@@ -355,13 +357,10 @@ static int ppa_in(ppa_struct *dev, char *buffer, int len) 
	case PPA_EPP_8:

		epp_reset(ppb);

		w_ctr(ppb, 0x24);

#ifdef CONFIG_SCSI_IZIP_EPP16

		if (!(((long) buffer | len) & 0x01))

			insw(ppb + 4, buffer, len >> 1);

#else

		if (!(((long) buffer | len) & 0x03))

		if (dev->mode == PPA_EPP_32 && !(((long) buffer | len) & 0x03))

			insl(ppb + 4, buffer, len >> 2);

#endif

		else if (dev->mode == PPA_EPP_16 && !(((long) buffer | len) & 0x01))

			insw(ppb + 4, buffer, len >> 1);

		else

			insb(ppb + 4, buffer, len);

		w_ctr(ppb, 0x2c);
@@ -469,6 +468,27 @@ static int ppa_init(ppa_struct *dev) 
{

	int retv;

	unsigned short ppb = dev->base;

	bool autodetect = dev->mode == PPA_AUTODETECT;



	if (autodetect) {

		int modes = dev->dev->port->modes;

		int ppb_hi = dev->dev->port->base_hi;



		/* Mode detection works up the chain of speed

		 * This avoids a nasty if-then-else-if-... tree

		 */

		dev->mode = PPA_NIBBLE;



		if (modes & PARPORT_MODE_TRISTATE)

			dev->mode = PPA_PS2;



		if (modes & PARPORT_MODE_ECP) {

			w_ecr(ppb_hi, 0x20);

			dev->mode = PPA_PS2;

		}

		if ((modes & PARPORT_MODE_EPP) && (modes & PARPORT_MODE_ECP))

			w_ecr(ppb_hi, 0x80);

	}



	ppa_disconnect(dev);

	ppa_connect(dev, CONNECT_NORMAL);
@@ -492,7 +512,7 @@ static int ppa_init(ppa_struct *dev) 
	if (retv)

		return -EIO;



	return device_check(dev);

	return device_check(dev, autodetect);

}



static inline int ppa_send_command(struct scsi_cmnd *cmd)
@@ -883,7 +903,7 @@ static int ppa_reset(struct scsi_cmnd *cmd) 
	return SUCCESS;

}



static int device_check(ppa_struct *dev)

static int device_check(ppa_struct *dev, bool autodetect)

{

	/* This routine looks for a device and then attempts to use EPP

	   to send a command. If all goes as planned then EPP is available. */
@@ -895,8 +915,8 @@ static int device_check(ppa_struct *dev) 
	old_mode = dev->mode;

	for (loop = 0; loop < 8; loop++) {

		/* Attempt to use EPP for Test Unit Ready */

		if ((ppb & 0x0007) == 0x0000)

			dev->mode = PPA_EPP_32;

		if (autodetect && (ppb & 0x0007) == 0x0000)

			dev->mode = PPA_EPP_8;



second_pass:

		ppa_connect(dev, CONNECT_EPP_MAYBE);
@@ -924,7 +944,7 @@ static int device_check(ppa_struct *dev) 
			udelay(1000);

			ppa_disconnect(dev);

			udelay(1000);

			if (dev->mode == PPA_EPP_32) {

			if (dev->mode != old_mode) {

				dev->mode = old_mode;

				goto second_pass;

			}
@@ -947,7 +967,7 @@ static int device_check(ppa_struct *dev) 
			udelay(1000);

			ppa_disconnect(dev);

			udelay(1000);

			if (dev->mode == PPA_EPP_32) {

			if (dev->mode != old_mode) {

				dev->mode = old_mode;

				goto second_pass;

			}
@@ -1026,7 +1046,6 @@ static int __ppa_attach(struct parport *pb) 
	DEFINE_WAIT(wait);

	ppa_struct *dev, *temp;

	int ports;

	int modes, ppb, ppb_hi;

	int err = -ENOMEM;

	struct pardev_cb ppa_cb;
@@ -1034,7 +1053,7 @@ static int __ppa_attach(struct parport *pb) 
	if (!dev)

		return -ENOMEM;

	dev->base = -1;

	dev->mode = PPA_AUTODETECT;

	dev->mode = mode < PPA_UNKNOWN ? mode : PPA_AUTODETECT;

	dev->recon_tmo = PPA_RECON_TMO;

	init_waitqueue_head(&waiting);

	temp = find_parent();
@@ -1069,25 +1088,8 @@ static int __ppa_attach(struct parport *pb) 
	}

	dev->waiting = NULL;

	finish_wait(&waiting, &wait);

	ppb = dev->base = dev->dev->port->base;

	ppb_hi = dev->dev->port->base_hi;

	w_ctr(ppb, 0x0c);

	modes = dev->dev->port->modes;



	/* Mode detection works up the chain of speed

	 * This avoids a nasty if-then-else-if-... tree

	 */

	dev->mode = PPA_NIBBLE;



	if (modes & PARPORT_MODE_TRISTATE)

		dev->mode = PPA_PS2;



	if (modes & PARPORT_MODE_ECP) {

		w_ecr(ppb_hi, 0x20);

		dev->mode = PPA_PS2;

	}

	if ((modes & PARPORT_MODE_EPP) && (modes & PARPORT_MODE_ECP))

		w_ecr(ppb_hi, 0x80);

	dev->base = dev->dev->port->base;

	w_ctr(dev->base, 0x0c);



	/* Done configuration */

drivers/scsi/ppa.h

+0 −4
Original line number Diff line number Diff line
@@ -107,11 +107,7 @@ static char *PPA_MODE_STRING[] = 
    "PS/2",

    "EPP 8 bit",

    "EPP 16 bit",

#ifdef CONFIG_SCSI_IZIP_EPP16

    "EPP 16 bit",

#else

    "EPP 32 bit",

#endif

    "Unknown"};



/* other options */