powerpc fixes for 4.17 #6

Just three commits.
 
 The two cxl ones are not fixes per se, but they modify code that was added this
 cycle so that it will work with a recent firmware change.
 
 And then a fix for a recent commit that added sleeps in the NVRAM code, which
 needs to be more careful and not sleep if eg. we're called in the panic() path.
 
 Thanks to:
   Nicholas Piggin, Philippe Bergheaud, Christophe Lombard.
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Merge tag 'powerpc-4.17-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "Just three commits.

  The two cxl ones are not fixes per se, but they modify code that was
  added this cycle so that it will work with a recent firmware change.

  And then a fix for a recent commit that added sleeps in the NVRAM
  code, which needs to be more careful and not sleep if eg. we're called
  in the panic() path.

  Thanks to Nicholas Piggin, Philippe Bergheaud, Christophe Lombard"

* tag 'powerpc-4.17-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/powernv: Fix NVRAM sleep in invalid context when crashing
  cxl: Report the tunneled operations status
  cxl: Set the PBCQ Tunnel BAR register when enabling capi mode

Documentation/ABI/testing/sysfs-class-cxl

@@ -244,3 +244,11 @@ Description:    read only
                 Returns 1 if the psl timebase register is synchronized
                 with the core timebase register, 0 otherwise.
 Users:          https://github.com/ibm-capi/libcxl
+
+What:           /sys/class/cxl/<card>/tunneled_ops_supported
+Date:           May 2018
+Contact:        linuxppc-dev@lists.ozlabs.org
+Description:    read only
+                Returns 1 if tunneled operations are supported in capi mode,
+                0 otherwise.
+Users:          https://github.com/ibm-capi/libcxl

arch/powerpc/platforms/powernv/opal-nvram.c

@@ -44,6 +44,10 @@ static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
 	return count;
 }
 
+/*
+ * This can be called in the panic path with interrupts off, so use
+ * mdelay in that case.
+ */
 static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
 {
 	s64 rc = OPAL_BUSY;
@@ -58,9 +62,15 @@ static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 		rc = opal_write_nvram(__pa(buf), count, off);
 		if (rc == OPAL_BUSY_EVENT) {
+			if (in_interrupt() || irqs_disabled())
+				mdelay(OPAL_BUSY_DELAY_MS);
+			else
 				msleep(OPAL_BUSY_DELAY_MS);
 			opal_poll_events(NULL);
 		} else if (rc == OPAL_BUSY) {
+			if (in_interrupt() || irqs_disabled())
+				mdelay(OPAL_BUSY_DELAY_MS);
+			else
 				msleep(OPAL_BUSY_DELAY_MS);
 		}
 	}

drivers/misc/cxl/cxl.h

@@ -717,6 +717,7 @@ struct cxl {
 	bool perst_select_user;
 	bool perst_same_image;
 	bool psl_timebase_synced;
+	bool tunneled_ops_supported;
 
 	/*
 	 * number of contexts mapped on to this card. Possible values are:

drivers/misc/cxl/pci.c

@@ -1742,6 +1742,15 @@ static int cxl_configure_adapter(struct cxl *adapter, struct pci_dev *dev)
 	/* Required for devices using CAPP DMA mode, harmless for others */
 	pci_set_master(dev);
 
+	adapter->tunneled_ops_supported = false;
+
+	if (cxl_is_power9()) {
+		if (pnv_pci_set_tunnel_bar(dev, 0x00020000E0000000ull, 1))
+			dev_info(&dev->dev, "Tunneled operations unsupported\n");
+		else
+			adapter->tunneled_ops_supported = true;
+	}
+
 	if ((rc = pnv_phb_to_cxl_mode(dev, adapter->native->sl_ops->capi_mode)))
 		goto err;
 
@@ -1768,6 +1777,9 @@ static void cxl_deconfigure_adapter(struct cxl *adapter)
 {
 	struct pci_dev *pdev = to_pci_dev(adapter->dev.parent);
 
+	if (cxl_is_power9())
+		pnv_pci_set_tunnel_bar(pdev, 0x00020000E0000000ull, 0);
+
 	cxl_native_release_psl_err_irq(adapter);
 	cxl_unmap_adapter_regs(adapter);
 

drivers/misc/cxl/sysfs.c

@@ -78,6 +78,15 @@ static ssize_t psl_timebase_synced_show(struct device *device,
 	return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->psl_timebase_synced);
 }
 
+static ssize_t tunneled_ops_supported_show(struct device *device,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct cxl *adapter = to_cxl_adapter(device);
+
+	return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->tunneled_ops_supported);
+}
+
 static ssize_t reset_adapter_store(struct device *device,
 				   struct device_attribute *attr,
 				   const char *buf, size_t count)
@@ -183,6 +192,7 @@ static struct device_attribute adapter_attrs[] = {
 	__ATTR_RO(base_image),
 	__ATTR_RO(image_loaded),
 	__ATTR_RO(psl_timebase_synced),
+	__ATTR_RO(tunneled_ops_supported),
 	__ATTR_RW(load_image_on_perst),
 	__ATTR_RW(perst_reloads_same_image),
 	__ATTR(reset, S_IWUSR, NULL, reset_adapter_store),