3 files changed, 56 insertions, 0 deletions

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),
 };