ipmi: Compensate for BMCs that wont set the irq enable bit

It appears that some BMCs support interrupts but don't support setting
the irq enable bits.  The interrupts are just always on.  Sigh.
Add code to compensate.

The new code was very similar to another functions, so this also
factors out the common code into other functions.
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Tested-by: Henrik Korkuc <henrik@kirneh.eu>

drivers/char/ipmi/ipmi_si_intf.c

@@ -262,9 +262,21 @@ struct smi_info {
 	bool supports_event_msg_buff;
 
 	/*
-	 * Can we clear the global enables receive irq bit?
+	 * Can we disable interrupts the global enables receive irq
+	 * bit?  There are currently two forms of brokenness, some
+	 * systems cannot disable the bit (which is technically within
+	 * the spec but a bad idea) and some systems have the bit
+	 * forced to zero even though interrupts work (which is
+	 * clearly outside the spec).  The next bool tells which form
+	 * of brokenness is present.
 	 */
-	bool cannot_clear_recv_irq_bit;
+	bool cannot_disable_irq;
+
+	/*
+	 * Some systems are broken and cannot set the irq enable
+	 * bit, even if they support interrupts.
+	 */
+	bool irq_enable_broken;
 
 	/*
 	 * Did we get an attention that we did not handle?
@@ -554,13 +566,14 @@ static u8 current_global_enables(struct smi_info *smi_info, u8 base,
 	if (smi_info->supports_event_msg_buff)
 		enables |= IPMI_BMC_EVT_MSG_BUFF;
 
-	if ((smi_info->irq && !smi_info->interrupt_disabled) ||
-	    smi_info->cannot_clear_recv_irq_bit)
+	if (((smi_info->irq && !smi_info->interrupt_disabled) ||
+	     smi_info->cannot_disable_irq) &&
+	    !smi_info->irq_enable_broken)
 		enables |= IPMI_BMC_RCV_MSG_INTR;
 
 	if (smi_info->supports_event_msg_buff &&
-	    smi_info->irq && !smi_info->interrupt_disabled)
-
+	    smi_info->irq && !smi_info->interrupt_disabled &&
+	    !smi_info->irq_enable_broken)
 		enables |= IPMI_BMC_EVT_MSG_INTR;
 
 	*irq_on = enables & (IPMI_BMC_EVT_MSG_INTR | IPMI_BMC_RCV_MSG_INTR);
@@ -2908,12 +2921,7 @@ static int try_get_dev_id(struct smi_info *smi_info)
 	return rv;
 }
 
-/*
- * Some BMCs do not support clearing the receive irq bit in the global
- * enables (even if they don't support interrupts on the BMC).  Check
- * for this and handle it properly.
- */
-static void check_clr_rcv_irq(struct smi_info *smi_info)
+static int get_global_enables(struct smi_info *smi_info, u8 *enables)
 {
 	unsigned char         msg[3];
 	unsigned char         *resp;
@@ -2921,12 +2929,8 @@ static void check_clr_rcv_irq(struct smi_info *smi_info)
 	int                   rv;
 
 	resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
-	if (!resp) {
-		printk(KERN_WARNING PFX "Out of memory allocating response for"
-		       " global enables command, cannot check recv irq bit"
-		       " handling.\n");
-		return;
-	}
+	if (!resp)
+		return -ENOMEM;
 
 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
 	msg[1] = IPMI_GET_BMC_GLOBAL_ENABLES_CMD;
@@ -2934,9 +2938,9 @@ static void check_clr_rcv_irq(struct smi_info *smi_info)
 
 	rv = wait_for_msg_done(smi_info);
 	if (rv) {
-		printk(KERN_WARNING PFX "Error getting response from get"
-		       " global enables command, cannot check recv irq bit"
-		       " handling.\n");
+		dev_warn(smi_info->dev,
+			 "Error getting response from get global enables command: %d\n",
+			 rv);
 		goto out;
 	}
 
@@ -2947,27 +2951,44 @@ static void check_clr_rcv_irq(struct smi_info *smi_info)
 			resp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2 ||
 			resp[1] != IPMI_GET_BMC_GLOBAL_ENABLES_CMD   ||
 			resp[2] != 0) {
-		printk(KERN_WARNING PFX "Invalid return from get global"
-		       " enables command, cannot check recv irq bit"
-		       " handling.\n");
+		dev_warn(smi_info->dev,
+			 "Invalid return from get global enables command: %ld %x %x %x\n",
+			 resp_len, resp[0], resp[1], resp[2]);
 		rv = -EINVAL;
 		goto out;
+	} else {
+		*enables = resp[3];
 	}
 
-	if ((resp[3] & IPMI_BMC_RCV_MSG_INTR) == 0)
-		/* Already clear, should work ok. */
-		goto out;
+out:
+	kfree(resp);
+	return rv;
+}
+
+/*
+ * Returns 1 if it gets an error from the command.
+ */
+static int set_global_enables(struct smi_info *smi_info, u8 enables)
+{
+	unsigned char         msg[3];
+	unsigned char         *resp;
+	unsigned long         resp_len;
+	int                   rv;
+
+	resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
+	if (!resp)
+		return -ENOMEM;
 
 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
 	msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
-	msg[2] = resp[3] & ~IPMI_BMC_RCV_MSG_INTR;
+	msg[2] = enables;
 	smi_info->handlers->start_transaction(smi_info->si_sm, msg, 3);
 
 	rv = wait_for_msg_done(smi_info);
 	if (rv) {
-		printk(KERN_WARNING PFX "Error getting response from set"
-		       " global enables command, cannot check recv irq bit"
-		       " handling.\n");
+		dev_warn(smi_info->dev,
+			 "Error getting response from set global enables command: %d\n",
+			 rv);
 		goto out;
 	}
 
@@ -2977,25 +2998,93 @@ static void check_clr_rcv_irq(struct smi_info *smi_info)
 	if (resp_len < 3 ||
 			resp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2 ||
 			resp[1] != IPMI_SET_BMC_GLOBAL_ENABLES_CMD) {
-		printk(KERN_WARNING PFX "Invalid return from get global"
-		       " enables command, cannot check recv irq bit"
-		       " handling.\n");
+		dev_warn(smi_info->dev,
+			 "Invalid return from set global enables command: %ld %x %x\n",
+			 resp_len, resp[0], resp[1]);
 		rv = -EINVAL;
 		goto out;
 	}
 
-	if (resp[2] != 0) {
+	if (resp[2] != 0)
+		rv = 1;
+
+out:
+	kfree(resp);
+	return rv;
+}
+
+/*
+ * Some BMCs do not support clearing the receive irq bit in the global
+ * enables (even if they don't support interrupts on the BMC).  Check
+ * for this and handle it properly.
+ */
+static void check_clr_rcv_irq(struct smi_info *smi_info)
+{
+	u8 enables = 0;
+	int rv;
+
+	rv = get_global_enables(smi_info, &enables);
+	if (!rv) {
+		if ((enables & IPMI_BMC_RCV_MSG_INTR) == 0)
+			/* Already clear, should work ok. */
+			return;
+
+		enables &= ~IPMI_BMC_RCV_MSG_INTR;
+		rv = set_global_enables(smi_info, enables);
+	}
+
+	if (rv < 0) {
+		dev_err(smi_info->dev,
+			"Cannot check clearing the rcv irq: %d\n", rv);
+		return;
+	}
+
+	if (rv) {
 		/*
 		 * An error when setting the event buffer bit means
 		 * clearing the bit is not supported.
 		 */
-		printk(KERN_WARNING PFX "The BMC does not support clearing"
-		       " the recv irq bit, compensating, but the BMC needs to"
-		       " be fixed.\n");
-		smi_info->cannot_clear_recv_irq_bit = true;
+		dev_warn(smi_info->dev,
+			 "The BMC does not support clearing the recv irq bit, compensating, but the BMC needs to be fixed.\n");
+		smi_info->cannot_disable_irq = true;
+	}
+}
+
+/*
+ * Some BMCs do not support setting the interrupt bits in the global
+ * enables even if they support interrupts.  Clearly bad, but we can
+ * compensate.
+ */
+static void check_set_rcv_irq(struct smi_info *smi_info)
+{
+	u8 enables = 0;
+	int rv;
+
+	if (!smi_info->irq)
+		return;
+
+	rv = get_global_enables(smi_info, &enables);
+	if (!rv) {
+		enables |= IPMI_BMC_RCV_MSG_INTR;
+		rv = set_global_enables(smi_info, enables);
+	}
+
+	if (rv < 0) {
+		dev_err(smi_info->dev,
+			"Cannot check setting the rcv irq: %d\n", rv);
+		return;
+	}
+
+	if (rv) {
+		/*
+		 * An error when setting the event buffer bit means
+		 * setting the bit is not supported.
+		 */
+		dev_warn(smi_info->dev,
+			 "The BMC does not support setting the recv irq bit, compensating, but the BMC needs to be fixed.\n");
+		smi_info->cannot_disable_irq = true;
+		smi_info->irq_enable_broken = true;
 	}
- out:
-	kfree(resp);
 }
 
 static int try_enable_event_buffer(struct smi_info *smi_info)
@@ -3316,6 +3405,12 @@ static void setup_xaction_handlers(struct smi_info *smi_info)
 	setup_dell_poweredge_bt_xaction_handler(smi_info);
 }
 
+static void check_for_broken_irqs(struct smi_info *smi_info)
+{
+	check_clr_rcv_irq(smi_info);
+	check_set_rcv_irq(smi_info);
+}
+
 static inline void wait_for_timer_and_thread(struct smi_info *smi_info)
 {
 	if (smi_info->thread != NULL)
@@ -3493,10 +3588,9 @@ static int try_smi_init(struct smi_info *new_smi)
 		goto out_err;
 	}
 
-	check_clr_rcv_irq(new_smi);
-
 	setup_oem_data_handler(new_smi);
 	setup_xaction_handlers(new_smi);
+	check_for_broken_irqs(new_smi);
 
 	new_smi->waiting_msg = NULL;
 	new_smi->curr_msg = NULL;