habanalabs: add skeleton driver

This patch adds the habanalabs skeleton driver. The driver does nothing at
this stage except very basic operations. It contains the minimal code to
insmod and rmmod the driver and to create a /dev/hlX file per PCI device.

Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 340 insertions, 0 deletions

diff --git a/drivers/misc/habanalabs/device.c b/drivers/misc/habanalabs/device.c
new file mode 100644
index 000000000000..6189fd0e2ccd
--- /dev/null
+++ b/drivers/misc/habanalabs/device.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright 2016-2019 HabanaLabs, Ltd.
+ * All Rights Reserved.
+ */
+
+#include "habanalabs.h"
+
+#include <linux/pci.h>
+#include <linux/delay.h>
+
+static void hpriv_release(struct kref *ref)
+{
+	struct hl_fpriv *hpriv;
+	struct hl_device *hdev;
+
+	hpriv = container_of(ref, struct hl_fpriv, refcount);
+
+	hdev = hpriv->hdev;
+
+	put_pid(hpriv->taskpid);
+
+	kfree(hpriv);
+}
+
+void hl_hpriv_get(struct hl_fpriv *hpriv)
+{
+	kref_get(&hpriv->refcount);
+}
+
+void hl_hpriv_put(struct hl_fpriv *hpriv)
+{
+	kref_put(&hpriv->refcount, hpriv_release);
+}
+
+/*
+ * hl_device_release - release function for habanalabs device
+ *
+ * @inode: pointer to inode structure
+ * @filp: pointer to file structure
+ *
+ * Called when process closes an habanalabs device
+ */
+static int hl_device_release(struct inode *inode, struct file *filp)
+{
+	struct hl_fpriv *hpriv = filp->private_data;
+
+	filp->private_data = NULL;
+
+	hl_hpriv_put(hpriv);
+
+	return 0;
+}
+
+static const struct file_operations hl_ops = {
+	.owner = THIS_MODULE,
+	.open = hl_device_open,
+	.release = hl_device_release
+};
+
+/*
+ * device_setup_cdev - setup cdev and device for habanalabs device
+ *
+ * @hdev: pointer to habanalabs device structure
+ * @hclass: pointer to the class object of the device
+ * @minor: minor number of the specific device
+ * @fpos : file operations to install for this device
+ *
+ * Create a cdev and a Linux device for habanalabs's device. Need to be
+ * called at the end of the habanalabs device initialization process,
+ * because this function exposes the device to the user
+ */
+static int device_setup_cdev(struct hl_device *hdev, struct class *hclass,
+				int minor, const struct file_operations *fops)
+{
+	int err, devno = MKDEV(hdev->major, minor);
+	struct cdev *hdev_cdev = &hdev->cdev;
+	char *name;
+
+	name = kasprintf(GFP_KERNEL, "hl%d", hdev->id);
+	if (!name)
+		return -ENOMEM;
+
+	cdev_init(hdev_cdev, fops);
+	hdev_cdev->owner = THIS_MODULE;
+	err = cdev_add(hdev_cdev, devno, 1);
+	if (err) {
+		pr_err("Failed to add char device %s\n", name);
+		goto err_cdev_add;
+	}
+
+	hdev->dev = device_create(hclass, NULL, devno, NULL, "%s", name);
+	if (IS_ERR(hdev->dev)) {
+		pr_err("Failed to create device %s\n", name);
+		err = PTR_ERR(hdev->dev);
+		goto err_device_create;
+	}
+
+	dev_set_drvdata(hdev->dev, hdev);
+
+	kfree(name);
+
+	return 0;
+
+err_device_create:
+	cdev_del(hdev_cdev);
+err_cdev_add:
+	kfree(name);
+	return err;
+}
+
+/*
+ * device_early_init - do some early initialization for the habanalabs device
+ *
+ * @hdev: pointer to habanalabs device structure
+ *
+ * Install the relevant function pointers and call the early_init function,
+ * if such a function exists
+ */
+static int device_early_init(struct hl_device *hdev)
+{
+	switch (hdev->asic_type) {
+	case ASIC_GOYA:
+		strlcpy(hdev->asic_name, "GOYA", sizeof(hdev->asic_name));
+		break;
+	default:
+		dev_err(hdev->dev, "Unrecognized ASIC type %d\n",
+			hdev->asic_type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * device_early_fini - finalize all that was done in device_early_init
+ *
+ * @hdev: pointer to habanalabs device structure
+ *
+ */
+static void device_early_fini(struct hl_device *hdev)
+{
+}
+
+/*
+ * hl_device_suspend - initiate device suspend
+ *
+ * @hdev: pointer to habanalabs device structure
+ *
+ * Puts the hw in the suspend state (all asics).
+ * Returns 0 for success or an error on failure.
+ * Called at driver suspend.
+ */
+int hl_device_suspend(struct hl_device *hdev)
+{
+	pci_save_state(hdev->pdev);
+
+	/* Shut down the device */
+	pci_disable_device(hdev->pdev);
+	pci_set_power_state(hdev->pdev, PCI_D3hot);
+
+	return 0;
+}
+
+/*
+ * hl_device_resume - initiate device resume
+ *
+ * @hdev: pointer to habanalabs device structure
+ *
+ * Bring the hw back to operating state (all asics).
+ * Returns 0 for success or an error on failure.
+ * Called at driver resume.
+ */
+int hl_device_resume(struct hl_device *hdev)
+{
+	int rc;
+
+	pci_set_power_state(hdev->pdev, PCI_D0);
+	pci_restore_state(hdev->pdev);
+	rc = pci_enable_device(hdev->pdev);
+	if (rc) {
+		dev_err(hdev->dev,
+			"Failed to enable PCI device in resume\n");
+		return rc;
+	}
+
+	return 0;
+}
+
+/*
+ * hl_device_init - main initialization function for habanalabs device
+ *
+ * @hdev: pointer to habanalabs device structure
+ *
+ * Allocate an id for the device, do early initialization and then call the
+ * ASIC specific initialization functions. Finally, create the cdev and the
+ * Linux device to expose it to the user
+ */
+int hl_device_init(struct hl_device *hdev, struct class *hclass)
+{
+	int rc;
+
+	/* Create device */
+	rc = device_setup_cdev(hdev, hclass, hdev->id, &hl_ops);
+
+	if (rc)
+		goto out_disabled;
+
+	/* Initialize ASIC function pointers and perform early init */
+	rc = device_early_init(hdev);
+	if (rc)
+		goto release_device;
+
+	dev_notice(hdev->dev,
+		"Successfully added device to habanalabs driver\n");
+
+	return 0;
+
+release_device:
+	device_destroy(hclass, hdev->dev->devt);
+	cdev_del(&hdev->cdev);
+out_disabled:
+	hdev->disabled = true;
+	if (hdev->pdev)
+		dev_err(&hdev->pdev->dev,
+			"Failed to initialize hl%d. Device is NOT usable !\n",
+			hdev->id);
+	else
+		pr_err("Failed to initialize hl%d. Device is NOT usable !\n",
+			hdev->id);
+
+	return rc;
+}
+
+/*
+ * hl_device_fini - main tear-down function for habanalabs device
+ *
+ * @hdev: pointer to habanalabs device structure
+ *
+ * Destroy the device, call ASIC fini functions and release the id
+ */
+void hl_device_fini(struct hl_device *hdev)
+{
+	dev_info(hdev->dev, "Removing device\n");
+
+	/* Mark device as disabled */
+	hdev->disabled = true;
+
+	device_early_fini(hdev);
+
+	/* Hide device from user */
+	device_destroy(hdev->dev->class, hdev->dev->devt);
+	cdev_del(&hdev->cdev);
+
+	pr_info("removed device successfully\n");
+}
+
+/*
+ * hl_poll_timeout_memory - Periodically poll a host memory address
+ *                              until it is not zero or a timeout occurs
+ * @hdev: pointer to habanalabs device structure
+ * @addr: Address to poll
+ * @timeout_us: timeout in us
+ * @val: Variable to read the value into
+ *
+ * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
+ * case, the last read value at @addr is stored in @val. Must not
+ * be called from atomic context if sleep_us or timeout_us are used.
+ *
+ * The function sleeps for 100us with timeout value of
+ * timeout_us
+ */
+int hl_poll_timeout_memory(struct hl_device *hdev, u64 addr,
+				u32 timeout_us, u32 *val)
+{
+	/*
+	 * address in this function points always to a memory location in the
+	 * host's (server's) memory. That location is updated asynchronously
+	 * either by the direct access of the device or by another core
+	 */
+	u32 *paddr = (u32 *) (uintptr_t) addr;
+	ktime_t timeout = ktime_add_us(ktime_get(), timeout_us);
+
+	might_sleep();
+
+	for (;;) {
+		/*
+		 * Flush CPU read/write buffers to make sure we read updates
+		 * done by other cores or by the device
+		 */
+		mb();
+		*val = *paddr;
+		if (*val)
+			break;
+		if (ktime_compare(ktime_get(), timeout) > 0) {
+			*val = *paddr;
+			break;
+		}
+		usleep_range((100 >> 2) + 1, 100);
+	}
+
+	return *val ? 0 : -ETIMEDOUT;
+}
+
+/*
+ * hl_poll_timeout_devicememory - Periodically poll a device memory address
+ *                                until it is not zero or a timeout occurs
+ * @hdev: pointer to habanalabs device structure
+ * @addr: Device address to poll
+ * @timeout_us: timeout in us
+ * @val: Variable to read the value into
+ *
+ * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
+ * case, the last read value at @addr is stored in @val. Must not
+ * be called from atomic context if sleep_us or timeout_us are used.
+ *
+ * The function sleeps for 100us with timeout value of
+ * timeout_us
+ */
+int hl_poll_timeout_device_memory(struct hl_device *hdev, void __iomem *addr,
+				u32 timeout_us, u32 *val)
+{
+	ktime_t timeout = ktime_add_us(ktime_get(), timeout_us);
+
+	might_sleep();
+
+	for (;;) {
+		*val = readl(addr);
+		if (*val)
+			break;
+		if (ktime_compare(ktime_get(), timeout) > 0) {
+			*val = readl(addr);
+			break;
+		}
+		usleep_range((100 >> 2) + 1, 100);
+	}
+
+	return *val ? 0 : -ETIMEDOUT;
+}