GenWQE: Add sysfs interface for bitstream reload

This patch adds an interface on sysfs for userspace to request a card
bitstream reload. It sets the appropriate register and try to perform a
fundamental reset on the PCIe slot for the card to reload the bitstream
from the chosen partition.

Signed-off-by: Kleber Sacilotto de Souza <klebers@linux.vnet.ibm.com>
Acked-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 115 insertions, 0 deletions

diff --git a/drivers/misc/genwqe/card_base.c b/drivers/misc/genwqe/card_base.c
index 74d51c9bb858..e6cc3e1e7326 100644
--- a/drivers/misc/genwqe/card_base.c
+++ b/drivers/misc/genwqe/card_base.c
@@ -761,6 +761,89 @@ static u64 genwqe_fir_checking(struct genwqe_dev *cd)
 }
 
 /**
+ * genwqe_pci_fundamental_reset() - trigger a PCIe fundamental reset on the slot
+ *
+ * Note: pci_set_pcie_reset_state() is not implemented on all archs, so this
+ * reset method will not work in all cases.
+ *
+ * Return: 0 on success or error code from pci_set_pcie_reset_state()
+ */
+static int genwqe_pci_fundamental_reset(struct pci_dev *pci_dev)
+{
+        int rc;
+
+        /*
+         * lock pci config space access from userspace,
+         * save state and issue PCIe fundamental reset
+         */
+        pci_cfg_access_lock(pci_dev);
+        pci_save_state(pci_dev);
+        rc = pci_set_pcie_reset_state(pci_dev, pcie_warm_reset);
+        if (!rc) {
+                /* keep PCIe reset asserted for 250ms */
+                msleep(250);
+                pci_set_pcie_reset_state(pci_dev, pcie_deassert_reset);
+                /* Wait for 2s to reload flash and train the link */
+                msleep(2000);
+        }
+        pci_restore_state(pci_dev);
+        pci_cfg_access_unlock(pci_dev);
+        return rc;
+}
+
+/*
+ * genwqe_reload_bistream() - reload card bitstream
+ *
+ * Set the appropriate register and call fundamental reset to reaload the card
+ * bitstream.
+ *
+ * Return: 0 on success, error code otherwise
+ */
+static int genwqe_reload_bistream(struct genwqe_dev *cd)
+{
+        struct pci_dev *pci_dev = cd->pci_dev;
+        int rc;
+
+        dev_info(&pci_dev->dev,
+                 "[%s] resetting card for bitstream reload\n",
+                 __func__);
+
+        genwqe_stop(cd);
+
+        /*
+         * Cause a CPLD reprogram with the 'next_bitstream'
+         * partition on PCIe hot or fundamental reset
+         */
+        __genwqe_writeq(cd, IO_SLC_CFGREG_SOFTRESET,
+                        (cd->softreset & 0xcull) | 0x70ull);
+
+        rc = genwqe_pci_fundamental_reset(pci_dev);
+        if (rc) {
+                /*
+                 * A fundamental reset failure can be caused
+                 * by lack of support on the arch, so we just
+                 * log the error and try to start the card
+                 * again.
+                 */
+                dev_err(&pci_dev->dev,
+                        "[%s] err: failed to reset card for bitstream reload\n",
+                        __func__);
+        }
+
+        rc = genwqe_start(cd);
+        if (rc) {
+                dev_err(&pci_dev->dev,
+                        "[%s] err: cannot start card services! (err=%d)\n",
+                        __func__, rc);
+                return rc;
+        }
+        dev_info(&pci_dev->dev,
+                 "[%s] card reloaded\n", __func__);
+        return 0;
+}
+
+
+/**
  * genwqe_health_thread() - Health checking thread
  *
  * This thread is only started for the PF of the card.
@@ -846,6 +929,13 @@ static int genwqe_health_thread(void *data)
                         }
                 }
 
+                if (cd->card_state == GENWQE_CARD_RELOAD_BITSTREAM) {
+                        /* Userspace requested card bitstream reload */
+                        rc = genwqe_reload_bistream(cd);
+                        if (rc)
+                                goto fatal_error;
+                }
+
                 cd->last_gfir = gfir;
                 cond_resched();
         }
diff --git a/drivers/misc/genwqe/card_sysfs.c b/drivers/misc/genwqe/card_sysfs.c
index a72a99266c3c..7232e40a3ad9 100644
--- a/drivers/misc/genwqe/card_sysfs.c
+++ b/drivers/misc/genwqe/card_sysfs.c
@@ -223,6 +223,30 @@ static ssize_t next_bitstream_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(next_bitstream);
 
+static ssize_t reload_bitstream_store(struct device *dev,
+                                struct device_attribute *attr,
+                                const char *buf, size_t count)
+{
+        int reload;
+        struct genwqe_dev *cd = dev_get_drvdata(dev);
+
+        if (kstrtoint(buf, 0, &reload) < 0)
+                return -EINVAL;
+
+        if (reload == 0x1) {
+                if (cd->card_state == GENWQE_CARD_UNUSED ||
+                    cd->card_state == GENWQE_CARD_USED)
+                        cd->card_state = GENWQE_CARD_RELOAD_BITSTREAM;
+                else
+                        return -EIO;
+        } else {
+                return -EINVAL;
+        }
+
+        return count;
+}
+static DEVICE_ATTR_WO(reload_bitstream);
+
 /*
  * Create device_attribute structures / params: name, mode, show, store
  * additional flag if valid in VF
@@ -239,6 +263,7 @@ static struct attribute *genwqe_attributes[] = {
         &dev_attr_status.attr,
         &dev_attr_freerunning_timer.attr,
         &dev_attr_queue_working_time.attr,
+        &dev_attr_reload_bitstream.attr,
         NULL,
 };