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

[Frank Haverkamp <haver@linux.vnet.ibm.com>]

Am Mittwoch, den 04.06.2014, 10:57 -0300 schrieb Kleber Sacilotto de
Souza:
> 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,
>  };
> 

Thanks for contributing those additions to our driver.

Acked-by: Frank Haverkamp <haver@linux.vnet.ibm.com>