4 files changed, 63 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-cxl b/Documentation/ABI/testing/sysfs-class-cxl
index 5941ff38d4a3..9ea01068a16c 100644
--- a/Documentation/ABI/testing/sysfs-class-cxl
+++ b/Documentation/ABI/testing/sysfs-class-cxl
@@ -146,3 +146,10 @@ Description:    read/write
                 user or factory image to be loaded.
                 Default is to reload on PERST whichever image the card has
                 loaded.
+
+What:           /sys/class/cxl/<card>/reset
+Date:           October 2014
+Contact:        linuxppc-dev@lists.ozlabs.org
+Description:    write only
+                Writing 1 will issue a PERST to card which may cause the card
+                to reload the FPGA depending on load_image_on_perst.
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index 518c4c6e6151..6a6a487464c5 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -489,6 +489,7 @@ int cxl_alloc_irq_ranges(struct cxl_irq_ranges *irqs, struct cxl *adapter, unsig
 void cxl_release_irq_ranges(struct cxl_irq_ranges *irqs, struct cxl *adapter);
 int cxl_setup_irq(struct cxl *adapter, unsigned int hwirq, unsigned int virq);
 int cxl_update_image_control(struct cxl *adapter);
+int cxl_reset(struct cxl *adapter);
 
 /* common == phyp + powernv */
 struct cxl_process_element_common {
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index a4a4e0217eed..428ea8ba25fc 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -21,6 +21,7 @@
 #include <asm/msi_bitmap.h>
 #include <asm/pci-bridge.h> /* for struct pci_controller */
 #include <asm/pnv-pci.h>
+#include <asm/io.h>
 
 #include "cxl.h"
 
@@ -741,6 +742,42 @@ static void cxl_remove_afu(struct cxl_afu *afu)
         device_unregister(&afu->dev);
 }
 
+int cxl_reset(struct cxl *adapter)
+{
+        struct pci_dev *dev = to_pci_dev(adapter->dev.parent);
+        int rc;
+        int i;
+        u32 val;
+
+        dev_info(&dev->dev, "CXL reset\n");
+
+        for (i = 0; i < adapter->slices; i++)
+                cxl_remove_afu(adapter->afu[i]);
+
+        /* pcie_warm_reset requests a fundamental pci reset which includes a
+         * PERST assert/deassert.  PERST triggers a loading of the image
+         * if "user" or "factory" is selected in sysfs */
+        if ((rc = pci_set_pcie_reset_state(dev, pcie_warm_reset))) {
+                dev_err(&dev->dev, "cxl: pcie_warm_reset failed\n");
+                return rc;
+        }
+
+        /* the PERST done above fences the PHB.  So, reset depends on EEH
+         * to unbind the driver, tell Sapphire to reinit the PHB, and rebind
+         * the driver.  Do an mmio read explictly to ensure EEH notices the
+         * fenced PHB.  Retry for a few seconds before giving up. */
+        i = 0;
+        while (((val = mmio_read32be(adapter->p1_mmio)) != 0xffffffff) &&
+                (i < 5)) {
+                msleep(500);
+                i++;
+        }
+
+        if (val != 0xffffffff)
+                dev_err(&dev->dev, "cxl: PERST failed to trigger EEH\n");
+
+        return rc;
+}
 
 static int cxl_map_adapter_regs(struct cxl *adapter, struct pci_dev *dev)
 {
diff --git a/drivers/misc/cxl/sysfs.c b/drivers/misc/cxl/sysfs.c
index ed4ad461143c..adf1f6d84913 100644
--- a/drivers/misc/cxl/sysfs.c
+++ b/drivers/misc/cxl/sysfs.c
@@ -56,6 +56,23 @@ static ssize_t image_loaded_show(struct device *device,
         return scnprintf(buf, PAGE_SIZE, "factory\n");
 }
 
+static ssize_t reset_adapter_store(struct device *device,
+                                   struct device_attribute *attr,
+                                   const char *buf, size_t count)
+{
+        struct cxl *adapter = to_cxl_adapter(device);
+        int rc;
+        int val;
+
+        rc = sscanf(buf, "%i", &val);
+        if ((rc != 1) || (val != 1))
+                return -EINVAL;
+
+        if ((rc = cxl_reset(adapter)))
+                return rc;
+        return count;
+}
+
 static ssize_t load_image_on_perst_show(struct device *device,
                                  struct device_attribute *attr,
                                  char *buf)
@@ -100,6 +117,7 @@ static struct device_attribute adapter_attrs[] = {
         __ATTR_RO(base_image),
         __ATTR_RO(image_loaded),
         __ATTR_RW(load_image_on_perst),
+        __ATTR(reset, S_IWUSR, NULL, reset_adapter_store),
 };