[PATCH v4 04/17] dmaengine: idxd: add support for readonly config devices

Dave Jiang
2020-10-30T18:53:25Z

The VFIO mediated device for idxd driver will provide a virtual DSA
device by backing it with a workqueue. The virtual device will be limited
with the wq configuration registers set to read-only. Add support and
helper functions for the handling of a DSA device with the configuration
registers marked as read-only.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
drivers/dma/idxd/device.c | 116 +++++++++++++++++++++++++++++++++++++++++++++
drivers/dma/idxd/idxd.h | 1
drivers/dma/idxd/init.c | 8 +++
drivers/dma/idxd/sysfs.c | 20 +++++---
4 files changed, 137 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index d6f551dcbcb6..7003884cd8ad 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -778,3 +778,119 @@ int idxd_device_config(struct idxd_device *idxd)

return 0;
}
+
+static int idxd_wq_load_config(struct idxd_wq *wq)
+{
+ struct idxd_device *idxd = wq->idxd;
+ struct device *dev = &idxd->pdev->dev;
+ int wqcfg_offset;
+ int i;
+
+ wqcfg_offset = WQCFG_OFFSET(idxd, wq->id, 0);
+ memcpy_fromio(wq->wqcfg, idxd->reg_base + wqcfg_offset, idxd->wqcfg_size);
+
+ wq->size = wq->wqcfg->wq_size;
+ wq->threshold = wq->wqcfg->wq_thresh;
+ if (wq->wqcfg->priv)
+ wq->type = IDXD_WQT_KERNEL;
+
+ /* The driver does not support shared WQ mode in read-only config yet */
+ if (wq->wqcfg->mode == 0 || wq->wqcfg->pasid_en)
+ return -EOPNOTSUPP;
+
+ set_bit(WQ_FLAG_DEDICATED, &wq->flags);
+
+ wq->priority = wq->wqcfg->priority;
+
+ for (i = 0; i < WQCFG_STRIDES(idxd); i++) {
+ wqcfg_offset = WQCFG_OFFSET(idxd, wq->id, i);
+ dev_dbg(dev, "WQ[%d][%d][%#x]: %#x\n", wq->id, i, wqcfg_offset, wq->wqcfg->bits[i]);
+ }
+
+ return 0;
+}
+
+static void idxd_group_load_config(struct idxd_group *group)
+{
+ struct idxd_device *idxd = group->idxd;
+ struct device *dev = &idxd->pdev->dev;
+ int i, j, grpcfg_offset;
+
+ /*
+ * Load WQS bit fields
+ * Iterate through all 256 bits 64 bits at a time
+ */
+ for (i = 0; i < GRPWQCFG_STRIDES; i++) {
+ struct idxd_wq *wq;
+
+ grpcfg_offset = GRPWQCFG_OFFSET(idxd, group->id, i);
+ group->grpcfg.wqs[i] = ioread64(idxd->reg_base + grpcfg_offset);
+ dev_dbg(dev, "GRPCFG wq[%d:%d: %#x]: %#llx\n",
+ group->id, i, grpcfg_offset, group->grpcfg.wqs[i]);
+
+ if (i * 64 >= idxd->max_wqs)
+ break;
+
+ /* Iterate through all 64 bits and check for wq set */
+ for (j = 0; j < 64; j++) {
+ int id = i * 64 + j;
+
+ /* No need to check beyond max wqs */
+ if (id >= idxd->max_wqs)
+ break;
+
+ /* Set group assignment for wq if wq bit is set */
+ if (group->grpcfg.wqs[i] & BIT(j)) {
+ wq = &idxd->wqs[id];
+ wq->group = group;
+ }
+ }
+ }
+
+ grpcfg_offset = GRPENGCFG_OFFSET(idxd, group->id);
+ group->grpcfg.engines = ioread64(idxd->reg_base + grpcfg_offset);
+ dev_dbg(dev, "GRPCFG engs[%d: %#x]: %#llx\n", group->id,
+ grpcfg_offset, group->grpcfg.engines);
+
+ /* Iterate through all 64 bits to check engines set */
+ for (i = 0; i < 64; i++) {
+ if (i >= idxd->max_engines)
+ break;
+
+ if (group->grpcfg.engines & BIT(i)) {
+ struct idxd_engine *engine = &idxd->engines[i];
+
+ engine->group = group;
+ }
+ }
+
+ grpcfg_offset = GRPFLGCFG_OFFSET(idxd, group->id);
+ group->grpcfg.flags.bits = ioread32(idxd->reg_base + grpcfg_offset);
+ dev_dbg(dev, "GRPFLAGS flags[%d: %#x]: %#x\n",
+ group->id, grpcfg_offset, group->grpcfg.flags.bits);
+}
+
+int idxd_device_load_config(struct idxd_device *idxd)
+{
+ union gencfg_reg reg;
+ int i, rc;
+
+ reg.bits = ioread32(idxd->reg_base + IDXD_GENCFG_OFFSET);
+ idxd->token_limit = reg.token_limit;
+
+ for (i = 0; i < idxd->max_groups; i++) {
+ struct idxd_group *group = &idxd->groups[i];
+
+ idxd_group_load_config(group);
+ }
+
+ for (i = 0; i < idxd->max_wqs; i++) {
+ struct idxd_wq *wq = &idxd->wqs[i];
+
+ rc = idxd_wq_load_config(wq);
+ if (rc < 0)
+ return rc;
+ }
+
+ return 0;
+}
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 7e54209c433a..1afc34be4ed0 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -317,6 +317,7 @@ void idxd_device_cleanup(struct idxd_device *idxd);
int idxd_device_config(struct idxd_device *idxd);
void idxd_device_wqs_clear_state(struct idxd_device *idxd);
void idxd_device_drain_pasid(struct idxd_device *idxd, int pasid);
+int idxd_device_load_config(struct idxd_device *idxd);

/* work queue control */
int idxd_wq_alloc_resources(struct idxd_wq *wq);
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 45b0eac640c3..98b1091181bb 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -349,6 +349,14 @@ static int idxd_probe(struct idxd_device *idxd)
if (rc)
goto err_setup;

+ /* If the configs are readonly, then load them from device */
+ if (!test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) {
+ dev_dbg(dev, "Loading RO device config\n");
+ rc = idxd_device_load_config(idxd);
+ if (rc < 0)
+ goto err_setup;
+ }
+
rc = idxd_setup_interrupts(idxd);
if (rc)
goto err_setup;
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 6d292eb79bf3..304eb2cf532e 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -102,7 +102,7 @@ static int idxd_config_bus_match(struct device *dev,

static int idxd_config_bus_probe(struct device *dev)
{
- int rc;
+ int rc = 0;
unsigned long flags;

dev_dbg(dev, "%s called\n", __func__);
@@ -120,7 +120,8 @@ static int idxd_config_bus_probe(struct device *dev)

/* Perform IDXD configuration and enabling */
spin_lock_irqsave(&idxd->dev_lock, flags);
- rc = idxd_device_config(idxd);
+ if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
+ rc = idxd_device_config(idxd);
spin_unlock_irqrestore(&idxd->dev_lock, flags);
if (rc < 0) {
module_put(THIS_MODULE);
@@ -207,7 +208,8 @@ static int idxd_config_bus_probe(struct device *dev)
}

spin_lock_irqsave(&idxd->dev_lock, flags);
- rc = idxd_device_config(idxd);
+ if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
+ rc = idxd_device_config(idxd);
spin_unlock_irqrestore(&idxd->dev_lock, flags);
if (rc < 0) {
mutex_unlock(&wq->wq_lock);
@@ -328,12 +330,14 @@ static int idxd_config_bus_remove(struct device *dev)

idxd_unregister_dma_device(idxd);
rc = idxd_device_disable(idxd);
- for (i = 0; i < idxd->max_wqs; i++) {
- struct idxd_wq *wq = &idxd->wqs[i];
+ if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) {
+ for (i = 0; i < idxd->max_wqs; i++) {
+ struct idxd_wq *wq = &idxd->wqs[i];

- mutex_lock(&wq->wq_lock);
- idxd_wq_disable_cleanup(wq);
- mutex_unlock(&wq->wq_lock);
+ mutex_lock(&wq->wq_lock);
+ idxd_wq_disable_cleanup(wq);
+ mutex_unlock(&wq->wq_lock);
+ }
}
module_put(THIS_MODULE);
if (rc < 0)