[SCSI] ipr: Write caching state host attribute

Adds a scsi_host sysfs attribute and module parm to enable/disable
the write cache on an ipr adapter.

Signed-off-by: Brian King <brking@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

2 files changed, 210 insertions, 9 deletions

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 8817ea06adbf..7149aada3f3c 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -91,6 +91,7 @@ static unsigned int ipr_max_speed = 1;
 static int ipr_testmode = 0;
 static unsigned int ipr_fastfail = 0;
 static unsigned int ipr_transop_timeout = IPR_OPERATIONAL_TIMEOUT;
+static unsigned int ipr_enable_cache = 1;
 static DEFINE_SPINLOCK(ipr_driver_lock);
 
 /* This table describes the differences between DMA controller chips */
@@ -150,6 +151,8 @@ module_param_named(fastfail, ipr_fastfail, int, 0);
 MODULE_PARM_DESC(fastfail, "Reduce timeouts and retries");
 module_param_named(transop_timeout, ipr_transop_timeout, int, 0);
 MODULE_PARM_DESC(transop_timeout, "Time in seconds to wait for adapter to come operational (default: 300)");
+module_param_named(enable_cache, ipr_enable_cache, int, 0);
+MODULE_PARM_DESC(enable_cache, "Enable adapter's non-volatile write cache (default: 1)");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(IPR_DRIVER_VERSION);
 
@@ -1937,6 +1940,103 @@ static struct bin_attribute ipr_trace_attr = {
 };
 #endif
 
+static const struct {
+        enum ipr_cache_state state;
+        char *name;
+} cache_state [] = {
+        { CACHE_NONE, "none" },
+        { CACHE_DISABLED, "disabled" },
+        { CACHE_ENABLED, "enabled" }
+};
+
+/**
+ * ipr_show_write_caching - Show the write caching attribute
+ * @class_dev:  class device struct
+ * @buf:                buffer
+ *
+ * Return value:
+ *      number of bytes printed to buffer
+ **/
+static ssize_t ipr_show_write_caching(struct class_device *class_dev, char *buf)
+{
+        struct Scsi_Host *shost = class_to_shost(class_dev);
+        struct ipr_ioa_cfg *ioa_cfg = (struct ipr_ioa_cfg *)shost->hostdata;
+        unsigned long lock_flags = 0;
+        int i, len = 0;
+
+        spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
+        for (i = 0; i < ARRAY_SIZE(cache_state); i++) {
+                if (cache_state[i].state == ioa_cfg->cache_state) {
+                        len = snprintf(buf, PAGE_SIZE, "%s\n", cache_state[i].name);
+                        break;
+                }
+        }
+        spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
+        return len;
+}
+
+
+/**
+ * ipr_store_write_caching - Enable/disable adapter write cache
+ * @class_dev:  class_device struct
+ * @buf:                buffer
+ * @count:              buffer size
+ *
+ * This function will enable/disable adapter write cache.
+ *
+ * Return value:
+ *      count on success / other on failure
+ **/
+static ssize_t ipr_store_write_caching(struct class_device *class_dev,
+                                        const char *buf, size_t count)
+{
+        struct Scsi_Host *shost = class_to_shost(class_dev);
+        struct ipr_ioa_cfg *ioa_cfg = (struct ipr_ioa_cfg *)shost->hostdata;
+        unsigned long lock_flags = 0;
+        enum ipr_cache_state new_state = CACHE_INVALID;
+        int i;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EACCES;
+        if (ioa_cfg->cache_state == CACHE_NONE)
+                return -EINVAL;
+
+        for (i = 0; i < ARRAY_SIZE(cache_state); i++) {
+                if (!strncmp(cache_state[i].name, buf, strlen(cache_state[i].name))) {
+                        new_state = cache_state[i].state;
+                        break;
+                }
+        }
+
+        if (new_state != CACHE_DISABLED && new_state != CACHE_ENABLED)
+                return -EINVAL;
+
+        spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
+        if (ioa_cfg->cache_state == new_state) {
+                spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
+                return count;
+        }
+
+        ioa_cfg->cache_state = new_state;
+        dev_info(&ioa_cfg->pdev->dev, "%s adapter write cache.\n",
+                 new_state == CACHE_ENABLED ? "Enabling" : "Disabling");
+        if (!ioa_cfg->in_reset_reload)
+                ipr_initiate_ioa_reset(ioa_cfg, IPR_SHUTDOWN_NORMAL);
+        spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
+        wait_event(ioa_cfg->reset_wait_q, !ioa_cfg->in_reset_reload);
+
+        return count;
+}
+
+static struct class_device_attribute ipr_ioa_cache_attr = {
+        .attr = {
+                .name =         "write_cache",
+                .mode =         S_IRUGO | S_IWUSR,
+        },
+        .show = ipr_show_write_caching,
+        .store = ipr_store_write_caching
+};
+
 /**
  * ipr_show_fw_version - Show the firmware version
  * @class_dev:  class device struct
@@ -2406,6 +2506,7 @@ static struct class_device_attribute *ipr_ioa_attrs[] = {
         &ipr_diagnostics_attr,
         &ipr_ioa_reset_attr,
         &ipr_update_fw_attr,
+        &ipr_ioa_cache_attr,
         NULL,
 };
 
@@ -4148,6 +4249,36 @@ static int ipr_set_supported_devs(struct ipr_cmnd *ipr_cmd)
 }
 
 /**
+ * ipr_setup_write_cache - Disable write cache if needed
+ * @ipr_cmd:    ipr command struct
+ *
+ * This function sets up adapters write cache to desired setting
+ *
+ * Return value:
+ *      IPR_RC_JOB_CONTINUE / IPR_RC_JOB_RETURN
+ **/
+static int ipr_setup_write_cache(struct ipr_cmnd *ipr_cmd)
+{
+        struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg;
+
+        ipr_cmd->job_step = ipr_set_supported_devs;
+        ipr_cmd->u.res = list_entry(ioa_cfg->used_res_q.next,
+                                    struct ipr_resource_entry, queue);
+
+        if (ioa_cfg->cache_state != CACHE_DISABLED)
+                return IPR_RC_JOB_CONTINUE;
+
+        ipr_cmd->ioarcb.res_handle = cpu_to_be32(IPR_IOA_RES_HANDLE);
+        ipr_cmd->ioarcb.cmd_pkt.request_type = IPR_RQTYPE_IOACMD;
+        ipr_cmd->ioarcb.cmd_pkt.cdb[0] = IPR_IOA_SHUTDOWN;
+        ipr_cmd->ioarcb.cmd_pkt.cdb[1] = IPR_SHUTDOWN_PREPARE_FOR_NORMAL;
+
+        ipr_do_req(ipr_cmd, ipr_reset_ioa_job, ipr_timeout, IPR_INTERNAL_TIMEOUT);
+
+        return IPR_RC_JOB_RETURN;
+}
+
+/**
  * ipr_get_mode_page - Locate specified mode page
  * @mode_pages: mode page buffer
  * @page_code:  page code to find
@@ -4358,10 +4489,7 @@ static int ipr_ioafp_mode_select_page28(struct ipr_cmnd *ipr_cmd)
                               ioa_cfg->vpd_cbs_dma + offsetof(struct ipr_misc_cbs, mode_pages),
                               length);
 
-        ipr_cmd->job_step = ipr_set_supported_devs;
-        ipr_cmd->u.res = list_entry(ioa_cfg->used_res_q.next,
-                                    struct ipr_resource_entry, queue);
-
+        ipr_cmd->job_step = ipr_setup_write_cache;
         ipr_do_req(ipr_cmd, ipr_reset_ioa_job, ipr_timeout, IPR_INTERNAL_TIMEOUT);
 
         LEAVE;
@@ -4581,6 +4709,27 @@ static void ipr_ioafp_inquiry(struct ipr_cmnd *ipr_cmd, u8 flags, u8 page,
 }
 
 /**
+ * ipr_inquiry_page_supported - Is the given inquiry page supported
+ * @page0:              inquiry page 0 buffer
+ * @page:               page code.
+ *
+ * This function determines if the specified inquiry page is supported.
+ *
+ * Return value:
+ *      1 if page is supported / 0 if not
+ **/
+static int ipr_inquiry_page_supported(struct ipr_inquiry_page0 *page0, u8 page)
+{
+        int i;
+
+        for (i = 0; i < min_t(u8, page0->len, IPR_INQUIRY_PAGE0_ENTRIES); i++)
+                if (page0->page[i] == page)
+                        return 1;
+
+        return 0;
+}
+
+/**
  * ipr_ioafp_page3_inquiry - Send a Page 3 Inquiry to the adapter.
  * @ipr_cmd:    ipr command struct
  *
@@ -4593,6 +4742,36 @@ static void ipr_ioafp_inquiry(struct ipr_cmnd *ipr_cmd, u8 flags, u8 page,
 static int ipr_ioafp_page3_inquiry(struct ipr_cmnd *ipr_cmd)
 {
         struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg;
+        struct ipr_inquiry_page0 *page0 = &ioa_cfg->vpd_cbs->page0_data;
+
+        ENTER;
+
+        if (!ipr_inquiry_page_supported(page0, 1))
+                ioa_cfg->cache_state = CACHE_NONE;
+
+        ipr_cmd->job_step = ipr_ioafp_query_ioa_cfg;
+
+        ipr_ioafp_inquiry(ipr_cmd, 1, 3,
+                          ioa_cfg->vpd_cbs_dma + offsetof(struct ipr_misc_cbs, page3_data),
+                          sizeof(struct ipr_inquiry_page3));
+
+        LEAVE;
+        return IPR_RC_JOB_RETURN;
+}
+
+/**
+ * ipr_ioafp_page0_inquiry - Send a Page 0 Inquiry to the adapter.
+ * @ipr_cmd:    ipr command struct
+ *
+ * This function sends a Page 0 inquiry to the adapter
+ * to retrieve supported inquiry pages.
+ *
+ * Return value:
+ *      IPR_RC_JOB_CONTINUE / IPR_RC_JOB_RETURN
+ **/
+static int ipr_ioafp_page0_inquiry(struct ipr_cmnd *ipr_cmd)
+{
+        struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg;
         char type[5];
 
         ENTER;
@@ -4602,11 +4781,11 @@ static int ipr_ioafp_page3_inquiry(struct ipr_cmnd *ipr_cmd)
         type[4] = '\0';
         ioa_cfg->type = simple_strtoul((char *)type, NULL, 16);
 
-        ipr_cmd->job_step = ipr_ioafp_query_ioa_cfg;
+        ipr_cmd->job_step = ipr_ioafp_page3_inquiry;
 
-        ipr_ioafp_inquiry(ipr_cmd, 1, 3,
-                          ioa_cfg->vpd_cbs_dma + offsetof(struct ipr_misc_cbs, page3_data),
-                          sizeof(struct ipr_inquiry_page3));
+        ipr_ioafp_inquiry(ipr_cmd, 1, 0,
+                          ioa_cfg->vpd_cbs_dma + offsetof(struct ipr_misc_cbs, page0_data),
+                          sizeof(struct ipr_inquiry_page0));
 
         LEAVE;
         return IPR_RC_JOB_RETURN;
@@ -4626,7 +4805,7 @@ static int ipr_ioafp_std_inquiry(struct ipr_cmnd *ipr_cmd)
         struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg;
 
         ENTER;
-        ipr_cmd->job_step = ipr_ioafp_page3_inquiry;
+        ipr_cmd->job_step = ipr_ioafp_page0_inquiry;
 
         ipr_ioafp_inquiry(ipr_cmd, 0, 0,
                           ioa_cfg->vpd_cbs_dma + offsetof(struct ipr_misc_cbs, ioa_vpd),
@@ -5629,6 +5808,10 @@ static void __devinit ipr_init_ioa_cfg(struct ipr_ioa_cfg *ioa_cfg,
         INIT_WORK(&ioa_cfg->work_q, ipr_worker_thread, ioa_cfg);
         init_waitqueue_head(&ioa_cfg->reset_wait_q);
         ioa_cfg->sdt_state = INACTIVE;
+        if (ipr_enable_cache)
+                ioa_cfg->cache_state = CACHE_ENABLED;
+        else
+                ioa_cfg->cache_state = CACHE_DISABLED;
 
         ipr_initialize_bus_attr(ioa_cfg);
 
diff --git a/drivers/scsi/ipr.h b/drivers/scsi/ipr.h
index b8c1603f99eb..6d9aef001fe7 100644
--- a/drivers/scsi/ipr.h
+++ b/drivers/scsi/ipr.h
@@ -541,6 +541,15 @@ struct ipr_inquiry_page3 {
         u8 patch_number[4];
 }__attribute__((packed));
 
+#define IPR_INQUIRY_PAGE0_ENTRIES 20
+struct ipr_inquiry_page0 {
+        u8 peri_qual_dev_type;
+        u8 page_code;
+        u8 reserved1;
+        u8 len;
+        u8 page[IPR_INQUIRY_PAGE0_ENTRIES];
+}__attribute__((packed));
+
 struct ipr_hostrcb_device_data_entry {
         struct ipr_vpd vpd;
         struct ipr_res_addr dev_res_addr;
@@ -731,6 +740,7 @@ struct ipr_resource_table {
 
 struct ipr_misc_cbs {
         struct ipr_ioa_vpd ioa_vpd;
+        struct ipr_inquiry_page0 page0_data;
         struct ipr_inquiry_page3 page3_data;
         struct ipr_mode_pages mode_pages;
         struct ipr_supported_device supp_dev;
@@ -813,6 +823,13 @@ enum ipr_sdt_state {
         DUMP_OBTAINED
 };
 
+enum ipr_cache_state {
+        CACHE_NONE,
+        CACHE_DISABLED,
+        CACHE_ENABLED,
+        CACHE_INVALID
+};
+
 /* Per-controller data */
 struct ipr_ioa_cfg {
         char eye_catcher[8];
@@ -829,6 +846,7 @@ struct ipr_ioa_cfg {
         u8 allow_cmds:1;
         u8 allow_ml_add_del:1;
 
+        enum ipr_cache_state cache_state;
         u16 type; /* CCIN of the card */
 
         u8 log_level;