NVMe: Use normal shutdown

The NVMe spec recommends using the shutdown normal sequence when safely
taking the controller offline instead of hitting CC.EN on the next
start-up to reset the controller. The spec recommends a minimum of 1
second for the shutdown complete. This patch waits 2 seconds to be on
the safe side.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

2 files changed, 28 insertions, 0 deletions

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index 1595ffba8a66..23bb5a70d810 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1221,6 +1221,30 @@ static int nvme_enable_ctrl(struct nvme_dev *dev, u64 cap)
         return nvme_wait_ready(dev, cap, true);
 }
 
+static int nvme_shutdown_ctrl(struct nvme_dev *dev)
+{
+        unsigned long timeout;
+        u32 cc;
+
+        cc = (readl(&dev->bar->cc) & ~NVME_CC_SHN_MASK) | NVME_CC_SHN_NORMAL;
+        writel(cc, &dev->bar->cc);
+
+        timeout = 2 * HZ + jiffies;
+        while ((readl(&dev->bar->csts) & NVME_CSTS_SHST_MASK) !=
+                                                        NVME_CSTS_SHST_CMPLT) {
+                msleep(100);
+                if (fatal_signal_pending(current))
+                        return -EINTR;
+                if (time_after(jiffies, timeout)) {
+                        dev_err(&dev->pci_dev->dev,
+                                "Device shutdown incomplete; abort shutdown\n");
+                        return -ENODEV;
+                }
+        }
+
+        return 0;
+}
+
 static int nvme_configure_admin_queue(struct nvme_dev *dev)
 {
         int result;
@@ -1943,6 +1967,8 @@ static void nvme_dev_shutdown(struct nvme_dev *dev)
         list_del_init(&dev->node);
         spin_unlock(&dev_list_lock);
 
+        if (dev->bar)
+                nvme_shutdown_ctrl(dev);
         nvme_dev_unmap(dev);
 }
 
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 3403c8f06fa0..26ebcf41c213 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -53,6 +53,7 @@ enum {
         NVME_CC_SHN_NONE        = 0 << 14,
         NVME_CC_SHN_NORMAL      = 1 << 14,
         NVME_CC_SHN_ABRUPT      = 2 << 14,
+        NVME_CC_SHN_MASK        = 3 << 14,
         NVME_CC_IOSQES          = 6 << 16,
         NVME_CC_IOCQES          = 4 << 20,
         NVME_CSTS_RDY           = 1 << 0,
@@ -60,6 +61,7 @@ enum {
         NVME_CSTS_SHST_NORMAL   = 0 << 2,
         NVME_CSTS_SHST_OCCUR    = 1 << 2,
         NVME_CSTS_SHST_CMPLT    = 2 << 2,
+        NVME_CSTS_SHST_MASK     = 3 << 2,
 };
 
 #define NVME_VS(major, minor)   (major << 16 | minor)