[PATCH 1/4] GenWQE: Add sysfs interface for bitstream reload

Kleber Sacilotto de Souza
2014-06-25T16:23:58Z

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>
---
Documentation/ABI/testing/sysfs-driver-genwqe | 9 +++
drivers/misc/genwqe/card_base.c | 90 +++++++++++++++++++++++++
drivers/misc/genwqe/card_sysfs.c | 25 +++++++
include/uapi/linux/genwqe/genwqe_card.h | 1 +
4 files changed, 125 insertions(+), 0 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-driver-genwqe b/Documentation/ABI/testing/sysfs-driver-genwqe
index 1870737..64ac6d5 100644
--- a/Documentation/ABI/testing/sysfs-driver-genwqe
+++ b/Documentation/ABI/testing/sysfs-driver-genwqe
@@ -25,6 +25,15 @@ Date: Oct 2013
Contact: haver@linux.vnet.ibm.com
Description: Interface to set the next bitstream to be used.

+What: /sys/class/genwqe/genwqe<n>_card/reload_bitstream
+Date: May 2014
+Contact: klebers@linux.vnet.ibm.com
+Description: Interface to trigger a PCIe card reset to reload the bitstream.
+ sudo sh -c 'echo 1 > \
+ /sys/class/genwqe/genwqe0_card/reload_bitstream'
+ If successfully, the card will come back with the bitstream set
+ on 'next_bitstream'.
+
What: /sys/class/genwqe/genwqe<n>_card/tempsens
Date: Oct 2013
Contact: haver@linux.vnet.ibm.com
diff --git a/drivers/misc/genwqe/card_base.c b/drivers/misc/genwqe/card_base.c
index 74d51c9..e6cc3e1 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 a72a992..7232e40 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,
};

diff --git a/include/uapi/linux/genwqe/genwqe_card.h b/include/uapi/linux/genwqe/genwqe_card.h
index 795e957..4fc065f 100644
--- a/include/uapi/linux/genwqe/genwqe_card.h
+++ b/include/uapi/linux/genwqe/genwqe_card.h
@@ -328,6 +328,7 @@ enum genwqe_card_state {
GENWQE_CARD_UNUSED = 0,
GENWQE_CARD_USED = 1,
GENWQE_CARD_FATAL_ERROR = 2,
+ GENWQE_CARD_RELOAD_BITSTREAM = 3,
GENWQE_CARD_STATE_MAX,
};

--
1.7.1