[PATCH 40/71] ncr5380: Introduce NCR5380_poll_politely2

From: Finn Thain
Date: Wed Nov 18 2015 - 03:59:25 EST

SCSI bus protocol sometimes requires monitoring two related conditions
simultaneously. Enhance NCR5380_poll_politely() for this purpose, and
put it to use in the arbitration algorithm. It will also find use in
pseudo DMA.

Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>

---
drivers/scsi/NCR5380.c | 68 +++++++++++++++++++++++++------------------
drivers/scsi/atari_NCR5380.c | 64 ++++++++++++++++++++++++----------------
2 files changed, 79 insertions(+), 53 deletions(-)

Index: linux/drivers/scsi/atari_NCR5380.c
===================================================================
--- linux.orig/drivers/scsi/atari_NCR5380.c 2015-11-18 19:33:53.000000000 +1100
+++ linux/drivers/scsi/atari_NCR5380.c 2015-11-18 19:33:55.000000000 +1100
@@ -457,11 +457,14 @@ static inline void initialize_SCp(struct
}

/**
- * NCR5380_poll_politely - wait for chip register value
+ * NCR5380_poll_politely2 - wait for two chip register values
* @instance: controller to poll
- * @reg: 5380 register to poll
- * @bit: Bitmask to check
- * @val: Value required to exit
+ * @reg1: 5380 register to poll
+ * @bit1: Bitmask to check
+ * @val1: Expected value
+ * @reg2: Second 5380 register to poll
+ * @bit2: Second bitmask to check
+ * @val2: Second expected value
* @wait: Time-out in jiffies
*
* Polls the chip in a reasonably efficient manner waiting for an
@@ -469,11 +472,12 @@ static inline void initialize_SCp(struct
* (if possible). In irq contexts the time-out is arbitrarily limited.
* Callers may hold locks as long as they are held in irq mode.
*
- * Returns 0 if event occurred otherwise -ETIMEDOUT.
+ * Returns 0 if either or both event(s) occurred otherwise -ETIMEDOUT.
*/

-static int NCR5380_poll_politely(struct Scsi_Host *instance,
- int reg, int bit, int val, int wait)
+static int NCR5380_poll_politely2(struct Scsi_Host *instance,
+ int reg1, int bit1, int val1,
+ int reg2, int bit2, int val2, int wait)
{
unsigned long start = jiffies;
unsigned long n;
@@ -481,7 +485,9 @@ static int NCR5380_poll_politely(struct
/* Busy-wait for up to 1 jiffy */
n = loops_per_jiffy;
do {
- if ((NCR5380_read(reg) & bit) == val)
+ if ((NCR5380_read(reg1) & bit1) == val1)
+ return 0;
+ if ((NCR5380_read(reg2) & bit2) == val2)
return 0;
cpu_relax();
} while (--n > 0);
@@ -493,7 +499,9 @@ static int NCR5380_poll_politely(struct
n = min(20000U, jiffies_to_usecs(wait));
do {
udelay(1);
- if ((NCR5380_read(reg) & bit) == val)
+ if ((NCR5380_read(reg1) & bit1) == val1)
+ return 0;
+ if ((NCR5380_read(reg2) & bit2) == val2)
return 0;
cpu_relax();
} while (--n > 0);
@@ -504,13 +512,22 @@ static int NCR5380_poll_politely(struct
/* Repeatedly sleep for 1 ms until deadline */
while (time_is_after_jiffies(start + wait)) {
schedule_timeout_uninterruptible(1);
- if ((NCR5380_read(reg) & bit) == val)
+ if ((NCR5380_read(reg1) & bit1) == val1)
+ return 0;
+ if ((NCR5380_read(reg2) & bit2) == val2)
return 0;
}

return -ETIMEDOUT;
}

+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);
+}
+
#include <linux/delay.h>

#if NDEBUG
@@ -1342,7 +1359,6 @@ static int NCR5380_select(struct Scsi_Ho
int len;
int err;
unsigned long flags;
- unsigned long timeout;

NCR5380_dprint(NDEBUG_ARBITRATION, instance);
dprintk(NDEBUG_ARBITRATION, "scsi%d: starting arbitration, id = %d\n", HOSTNO,
@@ -1372,20 +1388,18 @@ static int NCR5380_select(struct Scsi_Ho
*/

local_irq_restore(flags);
- timeout = jiffies + HZ;
- while (1) {
- if (time_is_before_jiffies(timeout)) {
- NCR5380_write(MODE_REG, MR_BASE);
- shost_printk(KERN_ERR, instance,
- "select: arbitration timeout\n");
- return -1;
- }
- if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE)) {
- /* Reselection interrupt */
- return -1;
- }
- if (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS)
- break;
+ err = NCR5380_poll_politely2(instance, MODE_REG, MR_ARBITRATE, 0,
+ INITIATOR_COMMAND_REG, ICR_ARBITRATION_PROGRESS,
+ ICR_ARBITRATION_PROGRESS, HZ);
+ if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE)) {
+ /* Reselection interrupt */
+ return -1;
+ }
+ if (err < 0) {
+ NCR5380_write(MODE_REG, MR_BASE);
+ shost_printk(KERN_ERR, instance,
+ "select: arbitration timeout\n");
+ return -1;
}

/* The SCSI-2 arbitration delay is 2.4 us */
Index: linux/drivers/scsi/NCR5380.c
===================================================================
--- linux.orig/drivers/scsi/NCR5380.c 2015-11-18 19:33:53.000000000 +1100
+++ linux/drivers/scsi/NCR5380.c 2015-11-18 19:33:55.000000000 +1100
@@ -262,11 +262,14 @@ static inline void initialize_SCp(struct
}

/**
- * NCR5380_poll_politely - wait for chip register value
+ * NCR5380_poll_politely2 - wait for two chip register values
* @instance: controller to poll
- * @reg: 5380 register to poll
- * @bit: Bitmask to check
- * @val: Value required to exit
+ * @reg1: 5380 register to poll
+ * @bit1: Bitmask to check
+ * @val1: Expected value
+ * @reg2: Second 5380 register to poll
+ * @bit2: Second bitmask to check
+ * @val2: Second expected value
* @wait: Time-out in jiffies
*
* Polls the chip in a reasonably efficient manner waiting for an
@@ -274,11 +277,12 @@ static inline void initialize_SCp(struct
* (if possible). In irq contexts the time-out is arbitrarily limited.
* Callers may hold locks as long as they are held in irq mode.
*
- * Returns 0 if event occurred otherwise -ETIMEDOUT.
+ * Returns 0 if either or both event(s) occurred otherwise -ETIMEDOUT.
*/

-static int NCR5380_poll_politely(struct Scsi_Host *instance,
- int reg, int bit, int val, int wait)
+static int NCR5380_poll_politely2(struct Scsi_Host *instance,
+ int reg1, int bit1, int val1,
+ int reg2, int bit2, int val2, int wait)
{
unsigned long start = jiffies;
unsigned long n;
@@ -286,7 +290,9 @@ static int NCR5380_poll_politely(struct
/* Busy-wait for up to 1 jiffy */
n = loops_per_jiffy;
do {
- if ((NCR5380_read(reg) & bit) == val)
+ if ((NCR5380_read(reg1) & bit1) == val1)
+ return 0;
+ if ((NCR5380_read(reg2) & bit2) == val2)
return 0;
cpu_relax();
} while (--n > 0);
@@ -298,7 +304,9 @@ static int NCR5380_poll_politely(struct
n = min(20000U, jiffies_to_usecs(wait));
do {
udelay(1);
- if ((NCR5380_read(reg) & bit) == val)
+ if ((NCR5380_read(reg1) & bit1) == val1)
+ return 0;
+ if ((NCR5380_read(reg2) & bit2) == val2)
return 0;
cpu_relax();
} while (--n > 0);
@@ -309,13 +317,22 @@ static int NCR5380_poll_politely(struct
/* Repeatedly sleep for 1 ms until deadline */
while (time_is_after_jiffies(start + wait)) {
schedule_timeout_uninterruptible(1);
- if ((NCR5380_read(reg) & bit) == val)
+ if ((NCR5380_read(reg1) & bit1) == val1)
+ return 0;
+ if ((NCR5380_read(reg2) & bit2) == val2)
return 0;
}

return -ETIMEDOUT;
}

+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);
+}
+
static struct {
unsigned char value;
const char *name;
@@ -1094,7 +1111,6 @@ static int NCR5380_select(struct Scsi_Ho
unsigned char *data;
int len;
int err;
- unsigned long timeout;

NCR5380_dprint(NDEBUG_ARBITRATION, instance);
dprintk(NDEBUG_ARBITRATION, "scsi%d : starting arbitration, id = %d\n", instance->host_no, instance->this_id);
@@ -1118,23 +1134,19 @@ static int NCR5380_select(struct Scsi_Ho
*/

spin_unlock_irq(instance->host_lock);
- timeout = jiffies + HZ;
- while (1) {
- if (time_is_before_jiffies(timeout)) {
- NCR5380_write(MODE_REG, MR_BASE);
- shost_printk(KERN_ERR, instance,
- "select: arbitration timeout\n");
- spin_lock_irq(instance->host_lock);
- return -1;
- }
- spin_lock_irq(instance->host_lock);
- if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE)) {
- /* Reselection interrupt */
- return -1;
- }
- if (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS)
- break;
- spin_unlock_irq(instance->host_lock);
+ err = NCR5380_poll_politely2(instance, MODE_REG, MR_ARBITRATE, 0,
+ INITIATOR_COMMAND_REG, ICR_ARBITRATION_PROGRESS,
+ ICR_ARBITRATION_PROGRESS, HZ);
+ spin_lock_irq(instance->host_lock);
+ if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE)) {
+ /* Reselection interrupt */
+ return -1;
+ }
+ if (err < 0) {
+ NCR5380_write(MODE_REG, MR_BASE);
+ shost_printk(KERN_ERR, instance,
+ "select: arbitration timeout\n");
+ return -1;
}

/* The SCSI-2 arbitration delay is 2.4 us */


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