crypto: qat - expose device state through sysfs for 4xxx

Expose the device state through an attribute in sysfs and allow to
change it. This is to stop and shutdown a QAT device in order to change
its configuration.

The state attribute has been added to a newly created `qat` attribute
group which will contain all _QAT specific_ attributes.

The logic that implements the sysfs entries is part of a new file,
adf_sysfs.c. This exposes an entry point to allow the driver to create
attributes.

The function that creates the sysfs attributes is called from the probe
function of the driver and not in the state machine init function to
allow the change of states even if the device is in the down state.

In order to restore the device configuration between a transition from
down to up, the function that configures the devices has been abstracted
into the HW data structure.

The `state` attribute is only exposed for qat_4xxx devices.

Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Co-developed-by: Tomasz Kowallik <tomaszx.kowalik@intel.com>
Signed-off-by: Tomasz Kowallik <tomaszx.kowalik@intel.com>
Reviewed-by: Adam Guerin <adam.guerin@intel.com>
Reviewed-by: Fiona Trahe <fiona.trahe@intel.com>
Reviewed-by: Wojciech Ziemba <wojciech.ziemba@intel.com>
Reviewed-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Documentation/ABI/testing/sysfs-driver-qat

@@ -0,0 +1,21 @@
+What:		/sys/bus/pci/devices/<BDF>/qat/state
+Date:		June 2022
+KernelVersion:	5.20
+Contact:	qat-linux@intel.com
+Description:	Reports the current state of the QAT device and allows to
+		change it.
+
+		This attribute is RW.
+
+		Returned values:
+			up: the device is up and running
+			down: the device is down
+
+		Allowed values:
+			up: initialize and start the device
+			down: stop the device and bring it down
+
+		It is possible to transition the device from up to down only
+		if the device is up and vice versa.
+
+		This attribute is only available for qat_4xxx devices.

drivers/crypto/qat/qat_4xxx/adf_4xxx_hw_data.c

@@ -357,6 +357,7 @@ void adf_init_hw_data_4xxx(struct adf_hw_device_data *hw_data)
 	hw_data->ring_pair_reset = adf_gen4_ring_pair_reset;
 	hw_data->enable_pm = adf_gen4_enable_pm;
 	hw_data->handle_pm_interrupt = adf_gen4_handle_pm_interrupt;
+	hw_data->dev_config = adf_crypto_dev_config;
 
 	adf_gen4_init_hw_csr_ops(&hw_data->csr_ops);
 	adf_gen4_init_pf_pfvf_ops(&hw_data->pfvf_ops);

drivers/crypto/qat/qat_4xxx/adf_4xxx_hw_data.h

@@ -70,5 +70,6 @@ enum icp_qat_4xxx_slice_mask {
 
 void adf_init_hw_data_4xxx(struct adf_hw_device_data *hw_data);
 void adf_clean_hw_data_4xxx(struct adf_hw_device_data *hw_data);
+int adf_crypto_dev_config(struct adf_accel_dev *accel_dev);
 
 #endif

drivers/crypto/qat/qat_4xxx/adf_drv.c

@@ -53,7 +53,7 @@ static int adf_cfg_dev_init(struct adf_accel_dev *accel_dev)
 	return 0;
 }
 
-static int adf_crypto_dev_config(struct adf_accel_dev *accel_dev)
+int adf_crypto_dev_config(struct adf_accel_dev *accel_dev)
 {
 	char key[ADF_CFG_MAX_KEY_LEN_IN_BYTES];
 	int banks = GET_MAX_BANKS(accel_dev);
@@ -289,6 +289,10 @@ static int adf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto out_err_disable_aer;
 	}
 
+	ret = adf_sysfs_init(accel_dev);
+	if (ret)
+		goto out_err_disable_aer;
+
 	ret = adf_crypto_dev_config(accel_dev);
 	if (ret)
 		goto out_err_disable_aer;

drivers/crypto/qat/qat_common/Makefile

@@ -10,6 +10,7 @@ intel_qat-objs := adf_cfg.o \
 	adf_transport.o \
 	adf_admin.o \
 	adf_hw_arbiter.o \
+	adf_sysfs.o \
 	adf_gen2_hw_data.o \
 	adf_gen4_hw_data.o \
 	adf_gen4_pm.o \

drivers/crypto/qat/qat_common/adf_accel_devices.h

@@ -199,6 +199,7 @@ struct adf_hw_device_data {
 	char *(*uof_get_name)(struct adf_accel_dev *accel_dev, u32 obj_num);
 	u32 (*uof_get_num_objs)(void);
 	u32 (*uof_get_ae_mask)(struct adf_accel_dev *accel_dev, u32 obj_num);
+	int (*dev_config)(struct adf_accel_dev *accel_dev);
 	struct adf_pfvf_ops pfvf_ops;
 	struct adf_hw_csr_ops csr_ops;
 	const char *fw_name;

drivers/crypto/qat/qat_common/adf_common_drv.h

@@ -127,6 +127,8 @@ void adf_vf_isr_resource_free(struct adf_accel_dev *accel_dev);
 
 int adf_pfvf_comms_disabled(struct adf_accel_dev *accel_dev);
 
+int adf_sysfs_init(struct adf_accel_dev *accel_dev);
+
 int qat_hal_init(struct adf_accel_dev *accel_dev);
 void qat_hal_deinit(struct icp_qat_fw_loader_handle *handle);
 int qat_hal_start(struct icp_qat_fw_loader_handle *handle);

drivers/crypto/qat/qat_common/adf_sysfs.c

@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0-only)
+/* Copyright(c) 2022 Intel Corporation */
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/pci.h>
+#include "adf_accel_devices.h"
+#include "adf_cfg.h"
+#include "adf_common_drv.h"
+
+static const char * const state_operations[] = {
+	[DEV_DOWN] = "down",
+	[DEV_UP] = "up",
+};
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct adf_accel_dev *accel_dev;
+	char *state;
+
+	accel_dev = adf_devmgr_pci_to_accel_dev(to_pci_dev(dev));
+	if (!accel_dev)
+		return -EINVAL;
+
+	state = adf_dev_started(accel_dev) ? "up" : "down";
+	return sysfs_emit(buf, "%s\n", state);
+}
+
+static ssize_t state_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	struct adf_accel_dev *accel_dev;
+	u32 accel_id;
+	int ret;
+
+	accel_dev = adf_devmgr_pci_to_accel_dev(to_pci_dev(dev));
+	if (!accel_dev)
+		return -EINVAL;
+
+	accel_id = accel_dev->accel_id;
+
+	if (adf_devmgr_in_reset(accel_dev) || adf_dev_in_use(accel_dev)) {
+		dev_info(dev, "Device qat_dev%d is busy\n", accel_id);
+		return -EBUSY;
+	}
+
+	ret = sysfs_match_string(state_operations, buf);
+	if (ret < 0)
+		return ret;
+
+	switch (ret) {
+	case DEV_DOWN:
+		if (!adf_dev_started(accel_dev)) {
+			dev_info(dev, "Device qat_dev%d already down\n",
+				 accel_id);
+			return -EINVAL;
+		}
+
+		dev_info(dev, "Stopping device qat_dev%d\n", accel_id);
+
+		adf_dev_stop(accel_dev);
+		adf_dev_shutdown(accel_dev);
+
+		break;
+	case DEV_UP:
+		if (adf_dev_started(accel_dev)) {
+			dev_info(dev, "Device qat_dev%d already up\n",
+				 accel_id);
+			return -EINVAL;
+		}
+
+		dev_info(dev, "Starting device qat_dev%d\n", accel_id);
+
+		ret = GET_HW_DATA(accel_dev)->dev_config(accel_dev);
+		if (!ret)
+			ret = adf_dev_init(accel_dev);
+		if (!ret)
+			ret = adf_dev_start(accel_dev);
+
+		if (ret < 0) {
+			dev_err(dev, "Failed to start device qat_dev%d\n",
+				accel_id);
+			adf_dev_stop(accel_dev);
+			adf_dev_shutdown(accel_dev);
+			return ret;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(state);
+
+static struct attribute *qat_attrs[] = {
+	&dev_attr_state.attr,
+	NULL,
+};
+
+static struct attribute_group qat_group = {
+	.attrs = qat_attrs,
+	.name = "qat",
+};
+
+int adf_sysfs_init(struct adf_accel_dev *accel_dev)
+{
+	int ret;
+
+	ret = devm_device_add_group(&GET_DEV(accel_dev), &qat_group);
+	if (ret) {
+		dev_err(&GET_DEV(accel_dev),
+			"Failed to create qat attribute group: %d\n", ret);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(adf_sysfs_init);