[SCSI] megaraid_sas: FW transition and q size changes

This patch has the following enhancements :
a. handles new transition states of FW to support controller hotplug.
b. It reduces by 1 the maximum cmds that the driver may send to FW.
c. Sends "Stop Processing" cmd to FW before returning failure from reset routine
d. Adds print in megasas_transition routine
e. Sends "RESET" flag to FW to do a soft reset of controller
to move from Operational to Ready state.
f. Sending correct pointer (cmd->sense) to pci_pool_free

Signed-off-by: Sumant Patro <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/megaraid/megaraid_sas.c

···
 	}
 
 	if (atomic_read(&instance->fw_outstanding)) {
+		/*
+		* Send signal to FW to stop processing any pending cmds.
+		* The controller will be taken offline by the OS now.
+		*/
+		writel(MFI_STOP_ADP,
+				&instance->reg_set->inbound_doorbell);
 		instance->hw_crit_error = 1;
 		return FAILED;
 	}
···
 
 	fw_state = instance->instancet->read_fw_status_reg(instance->reg_set) & MFI_STATE_MASK;
 
+	if (fw_state != MFI_STATE_READY)
+ 		printk(KERN_INFO "megasas: Waiting for FW to come to ready"
+ 		       " state\n");
+
 	while (fw_state != MFI_STATE_READY) {
 
-		printk(KERN_INFO "megasas: Waiting for FW to come to ready"
-		       " state\n");
 		switch (fw_state) {
 
 		case MFI_STATE_FAULT:
···
 			/*
 			 * Set the CLR bit in inbound doorbell
 			 */
-			writel(MFI_INIT_CLEAR_HANDSHAKE,
+			writel(MFI_INIT_CLEAR_HANDSHAKE|MFI_INIT_HOTPLUG,
 				&instance->reg_set->inbound_doorbell);
 
 			max_wait = 2;
 			cur_state = MFI_STATE_WAIT_HANDSHAKE;
 			break;
 
+		case MFI_STATE_BOOT_MESSAGE_PENDING:
+			writel(MFI_INIT_HOTPLUG,
+				&instance->reg_set->inbound_doorbell);
+
+			max_wait = 10;
+			cur_state = MFI_STATE_BOOT_MESSAGE_PENDING;
+			break;
+
 		case MFI_STATE_OPERATIONAL:
 			/*
-			 * Bring it to READY state; assuming max wait 2 secs
+			 * Bring it to READY state; assuming max wait 10 secs
 			 */
 			megasas_disable_intr(instance);
-			writel(MFI_INIT_READY, &instance->reg_set->inbound_doorbell);
+			writel(MFI_RESET_FLAGS, &instance->reg_set->inbound_doorbell);
 
 			max_wait = 10;
 			cur_state = MFI_STATE_OPERATIONAL;
···
 			return -ENODEV;
 		}
 	};
+ 	printk(KERN_INFO "megasas: FW now in Ready state\n");
 
 	return 0;
 }
···
 				      cmd->frame_phys_addr);
 
 		if (cmd->sense)
-			pci_pool_free(instance->sense_dma_pool, cmd->frame,
+			pci_pool_free(instance->sense_dma_pool, cmd->sense,
 				      cmd->sense_phys_addr);
 	}
 
···
 	 * Get various operational parameters from status register
 	 */
 	instance->max_fw_cmds = instance->instancet->read_fw_status_reg(reg_set) & 0x00FFFF;
+	/*
+	 * Reduce the max supported cmds by 1. This is to ensure that the
+	 * reply_q_sz (1 more than the max cmd that driver may send)
+	 * does not exceed max cmds that the FW can support
+	 */
+	instance->max_fw_cmds = instance->max_fw_cmds-1;
 	instance->max_num_sge = (instance->instancet->read_fw_status_reg(reg_set) & 0xFF0000) >> 
 					0x10;
 	/*

drivers/scsi/megaraid/megaraid_sas.h

···
 #define MFI_STATE_WAIT_HANDSHAKE		0x60000000
 #define MFI_STATE_FW_INIT_2			0x70000000
 #define MFI_STATE_DEVICE_SCAN			0x80000000
+#define MFI_STATE_BOOT_MESSAGE_PENDING		0x90000000
 #define MFI_STATE_FLUSH_CACHE			0xA0000000
 #define MFI_STATE_READY				0xB0000000
 #define MFI_STATE_OPERATIONAL			0xC0000000
···
  * READY	: Move from OPERATIONAL to READY state; discard queue info
  * MFIMODE	: Discard (possible) low MFA posted in 64-bit mode (??)
  * CLR_HANDSHAKE: FW is waiting for HANDSHAKE from BIOS or Driver
+ * HOTPLUG	: Resume from Hotplug
+ * MFI_STOP_ADP	: Send signal to FW to stop processing
  */
-#define MFI_INIT_ABORT				0x00000000
+#define MFI_INIT_ABORT				0x00000001
 #define MFI_INIT_READY				0x00000002
 #define MFI_INIT_MFIMODE			0x00000004
 #define MFI_INIT_CLEAR_HANDSHAKE		0x00000008
-#define MFI_RESET_FLAGS				MFI_INIT_READY|MFI_INIT_MFIMODE
+#define MFI_INIT_HOTPLUG			0x00000010
+#define MFI_STOP_ADP				0x00000020
+#define MFI_RESET_FLAGS				MFI_INIT_READY| \
+						MFI_INIT_MFIMODE| \
+						MFI_INIT_ABORT
 
 /**
  * MFI frame flags