dmaengine: idxd: Add support for device/wq defaults

Add a load_device_defaults() function pointer to struct
idxd_driver_data, which if defined, will be called when an idxd device
is probed and will allow the idxd device to be configured with default
values.

The load_device_defaults() function is passed an idxd device to work
with to set specific device attributes.

Also add a load_device_defaults() implementation IAA devices; future
patches would add default functions for other device types such as
DSA.

The way idxd device probing works, if the device configuration is
valid at that point e.g. at least one workqueue and engine is properly
configured then the device will be enabled and ready to go.

The IAA implementation, idxd_load_iaa_device_defaults(), configures a
single workqueue (wq0) for each device with the following default
values:

mode "dedicated"
threshold 0
size Total WQ Size from WQCAP
priority 10
type IDXD_WQT_KERNEL
group 0
name "iaa_crypto"
driver_name "crypto"

Note that this now adds another configuration step for any users that
want to configure their own devices/workqueus with something different
in that they'll first need to disable (in the case of IAA) wq0 and the
device itself before they can set their own attributes and re-enable,
since they've been already been auto-enabled. Note also that in order
for the new configuration to be applied to the deflate-iaa crypto
algorithm the iaa_crypto module needs to unregister the old version,
which is accomplished by removing the iaa_crypto module, and
re-registering it with the new configuration by reinserting the
iaa_crypto module.

Signed-off-by: Tom Zanussi <[e-mail]>
Reviewed-by: Dave Jiang <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/dma/idxd/Makefile

···
 idxd_bus-y := bus.o
 
 obj-$(CONFIG_INTEL_IDXD) += idxd.o
-idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o cdev.o debugfs.o
+idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o cdev.o debugfs.o defaults.o
 
 idxd-$(CONFIG_INTEL_IDXD_PERFMON) += perfmon.o
 

drivers/dma/idxd/defaults.c

···
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2023 Intel Corporation. All rights rsvd. */
+#include <linux/kernel.h>
+#include "idxd.h"
+
+int idxd_load_iaa_device_defaults(struct idxd_device *idxd)
+{
+	struct idxd_engine *engine;
+	struct idxd_group *group;
+	struct idxd_wq *wq;
+
+	if (!test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
+		return 0;
+
+	wq = idxd->wqs[0];
+
+	if (wq->state != IDXD_WQ_DISABLED)
+		return -EPERM;
+
+	/* set mode to "dedicated" */
+	set_bit(WQ_FLAG_DEDICATED, &wq->flags);
+	wq->threshold = 0;
+
+	/* only setting up 1 wq, so give it all the wq space */
+	wq->size = idxd->max_wq_size;
+
+	/* set priority to 10 */
+	wq->priority = 10;
+
+	/* set type to "kernel" */
+	wq->type = IDXD_WQT_KERNEL;
+
+	/* set wq group to 0 */
+	group = idxd->groups[0];
+	wq->group = group;
+	group->num_wqs++;
+
+	/* set name to "iaa_crypto" */
+	memset(wq->name, 0, WQ_NAME_SIZE + 1);
+	strscpy(wq->name, "iaa_crypto", WQ_NAME_SIZE + 1);
+
+	/* set driver_name to "crypto" */
+	memset(wq->driver_name, 0, DRIVER_NAME_SIZE + 1);
+	strscpy(wq->driver_name, "crypto", DRIVER_NAME_SIZE + 1);
+
+	engine = idxd->engines[0];
+
+	/* set engine group to 0 */
+	engine->group = idxd->groups[0];
+	engine->group->num_engines++;
+
+	return 0;
+}

drivers/dma/idxd/idxd.h

···
 	struct dma_device dma;
 };
 
+typedef int (*load_device_defaults_fn_t) (struct idxd_device *idxd);
+
 struct idxd_driver_data {
 	const char *name_prefix;
 	enum idxd_type type;
···
 	int evl_cr_off;
 	int cr_status_off;
 	int cr_result_off;
+	load_device_defaults_fn_t load_device_defaults;
 };
 
 struct idxd_evl {
···
 void idxd_wqs_quiesce(struct idxd_device *idxd);
 bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc);
 void multi_u64_to_bmap(unsigned long *bmap, u64 *val, int count);
+int idxd_load_iaa_device_defaults(struct idxd_device *idxd);
 
 /* device interrupt control */
 irqreturn_t idxd_misc_thread(int vec, void *data);

drivers/dma/idxd/init.c

···
 		.evl_cr_off = offsetof(struct iax_evl_entry, cr),
 		.cr_status_off = offsetof(struct iax_completion_record, status),
 		.cr_result_off = offsetof(struct iax_completion_record, error_code),
+		.load_device_defaults = idxd_load_iaa_device_defaults,
 	},
 };
 
···
 	if (rc) {
 		dev_err(dev, "Intel(R) IDXD DMA Engine init failed\n");
 		goto err;
+	}
+
+	if (data->load_device_defaults) {
+		rc = data->load_device_defaults(idxd);
+		if (rc)
+			dev_warn(dev, "IDXD loading device defaults failed\n");
 	}
 
 	rc = idxd_register_devices(idxd);