[PATCH 09/17] cxlflash: Create character device to provide host management interface
Uma Krishnan
ukrishn at linux.vnet.ibm.com
Thu Jun 22 12:15:18 AEST 2017
The cxlflash driver currently lacks host management interface. Future
devices supported by cxlflash will provide a variety of host-wide
management functions. Examples include LUN provisioning, hardware debug
support, and firmware download.
In order to provide a way to manage the device, a character device will
be created during probe of each adapter. This device will support a set of
ioctls defined in the SISLite specification from which administrators can
manage the adapter.
Signed-off-by: Uma Krishnan <ukrishn at linux.vnet.ibm.com>
---
drivers/scsi/cxlflash/common.h | 6 +-
drivers/scsi/cxlflash/main.c | 207 ++++++++++++++++++++++++++++++++++++++++-
drivers/scsi/cxlflash/main.h | 1 +
3 files changed, 212 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h
index 11a5b0a..cbc0eb7 100644
--- a/drivers/scsi/cxlflash/common.h
+++ b/drivers/scsi/cxlflash/common.h
@@ -16,6 +16,7 @@
#define _CXLFLASH_COMMON_H
#include <linux/async.h>
+#include <linux/cdev.h>
#include <linux/irq_poll.h>
#include <linux/list.h>
#include <linux/rwsem.h>
@@ -86,7 +87,8 @@ enum cxlflash_init_state {
INIT_STATE_NONE,
INIT_STATE_PCI,
INIT_STATE_AFU,
- INIT_STATE_SCSI
+ INIT_STATE_SCSI,
+ INIT_STATE_CDEV
};
enum cxlflash_state {
@@ -116,6 +118,8 @@ struct cxlflash_cfg {
struct pci_device_id *dev_id;
struct Scsi_Host *host;
int num_fc_ports;
+ struct cdev cdev;
+ struct device *chardev;
ulong cxlflash_regs_pci;
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index ceb247b..0656dd2 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -34,6 +34,10 @@ MODULE_AUTHOR("Manoj N. Kumar <manoj at linux.vnet.ibm.com>");
MODULE_AUTHOR("Matthew R. Ochs <mrochs at linux.vnet.ibm.com>");
MODULE_LICENSE("GPL");
+static struct class *cxlflash_class;
+static u32 cxlflash_major;
+static DECLARE_BITMAP(cxlflash_minor, CXLFLASH_MAX_ADAPTERS);
+
/**
* process_cmd_err() - command error handler
* @cmd: AFU command that experienced the error.
@@ -863,6 +867,47 @@ static void notify_shutdown(struct cxlflash_cfg *cfg, bool wait)
}
/**
+ * cxlflash_get_minor() - gets the first available minor number
+ *
+ * Return: Unique minor number that can be used to create the character device.
+ */
+static int cxlflash_get_minor(void)
+{
+ int minor;
+ long bit;
+
+ bit = find_first_zero_bit(cxlflash_minor, CXLFLASH_MAX_ADAPTERS);
+ if (bit >= CXLFLASH_MAX_ADAPTERS)
+ return -1;
+
+ minor = bit & MINORMASK;
+ set_bit(minor, cxlflash_minor);
+ return minor;
+}
+
+/**
+ * cxlflash_put_minor() - releases the minor number
+ * @minor: Minor number that is no longer needed.
+ */
+static void cxlflash_put_minor(int minor)
+{
+ clear_bit(minor, cxlflash_minor);
+}
+
+/**
+ * cxlflash_release_chrdev() - release the character device for the host
+ * @cfg: Internal structure associated with the host.
+ */
+static void cxlflash_release_chrdev(struct cxlflash_cfg *cfg)
+{
+ put_device(cfg->chardev);
+ device_unregister(cfg->chardev);
+ cfg->chardev = NULL;
+ cdev_del(&cfg->cdev);
+ cxlflash_put_minor(MINOR(cfg->cdev.dev));
+}
+
+/**
* cxlflash_remove() - PCI entry point to tear down host
* @pdev: PCI device associated with the host.
*
@@ -897,6 +942,8 @@ static void cxlflash_remove(struct pci_dev *pdev)
cxlflash_stop_term_user_contexts(cfg);
switch (cfg->init_state) {
+ case INIT_STATE_CDEV:
+ cxlflash_release_chrdev(cfg);
case INIT_STATE_SCSI:
cxlflash_term_local_luns(cfg);
scsi_remove_host(cfg->host);
@@ -3120,6 +3167,86 @@ static void cxlflash_worker_thread(struct work_struct *work)
}
/**
+ * cxlflash_chr_open() - character device open handler
+ * @inode: Device inode associated with this character device.
+ * @file: File pointer for this device.
+ *
+ * Only users with admin privileges are allowed to open the character device.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int cxlflash_chr_open(struct inode *inode, struct file *file)
+{
+ struct cxlflash_cfg *cfg;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ cfg = container_of(inode->i_cdev, struct cxlflash_cfg, cdev);
+ file->private_data = cfg;
+
+ return 0;
+}
+
+/*
+ * Character device file operations
+ */
+static const struct file_operations cxlflash_chr_fops = {
+ .owner = THIS_MODULE,
+ .open = cxlflash_chr_open,
+};
+
+/**
+ * init_chrdev() - initialize the character device for the host
+ * @cfg: Internal structure associated with the host.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int init_chrdev(struct cxlflash_cfg *cfg)
+{
+ struct device *dev = &cfg->dev->dev;
+ struct device *char_dev;
+ dev_t devno;
+ int minor;
+ int rc = 0;
+
+ minor = cxlflash_get_minor();
+ if (unlikely(minor < 0)) {
+ dev_err(dev, "%s: Exhausted allowed adapters\n", __func__);
+ rc = -ENOSPC;
+ goto out;
+ }
+
+ devno = MKDEV(cxlflash_major, minor);
+ cdev_init(&cfg->cdev, &cxlflash_chr_fops);
+
+ rc = cdev_add(&cfg->cdev, devno, 1);
+ if (rc) {
+ dev_err(dev, "%s: cdev_add failed rc=%d\n", __func__, rc);
+ goto err1;
+ }
+
+ char_dev = device_create(cxlflash_class, NULL, devno,
+ NULL, "cxlflash%d", minor);
+ if (IS_ERR(char_dev)) {
+ rc = PTR_ERR(char_dev);
+ dev_err(dev, "%s: device_create failed rc=%d\n",
+ __func__, rc);
+ goto err2;
+ }
+
+ cfg->chardev = char_dev;
+out:
+ dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
+ return rc;
+err2:
+ cdev_del(&cfg->cdev);
+err1:
+ cxlflash_put_minor(minor);
+ goto out;
+}
+
+/**
* cxlflash_probe() - PCI entry point to add host
* @pdev: PCI device associated with the host.
* @dev_id: PCI device id associated with device.
@@ -3229,6 +3356,13 @@ static int cxlflash_probe(struct pci_dev *pdev,
}
cfg->init_state = INIT_STATE_SCSI;
+ rc = init_chrdev(cfg);
+ if (rc) {
+ dev_err(dev, "%s: init_chrdev failed rc=%d\n", __func__, rc);
+ goto out_remove;
+ }
+ cfg->init_state = INIT_STATE_CDEV;
+
if (wq_has_sleeper(&cfg->reset_waitq)) {
cfg->state = STATE_PROBED;
wake_up_all(&cfg->reset_waitq);
@@ -3331,6 +3465,63 @@ static void cxlflash_pci_resume(struct pci_dev *pdev)
scsi_unblock_requests(cfg->host);
}
+/**
+ * cxlflash_devnode() - provides devtmpfs for devices in the cxlflash class
+ * @dev: Character device.
+ * @mode: Mode that can be used to verify access.
+ *
+ * Return: Allocated string describing the devtmpfs structure.
+ */
+static char *cxlflash_devnode(struct device *dev, umode_t *mode)
+{
+ return kasprintf(GFP_KERNEL, "cxlflash/%s", dev_name(dev));
+}
+
+/**
+ * cxlflash_class_init() - create character device class
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int cxlflash_class_init(void)
+{
+ dev_t devno;
+ int rc = 0;
+
+ rc = alloc_chrdev_region(&devno, 0, CXLFLASH_MAX_ADAPTERS, "cxlflash");
+ if (unlikely(rc)) {
+ pr_err("%s: alloc_chrdev_region failed rc=%d\n", __func__, rc);
+ goto out;
+ }
+
+ cxlflash_major = MAJOR(devno);
+
+ cxlflash_class = class_create(THIS_MODULE, "cxlflash");
+ if (IS_ERR(cxlflash_class)) {
+ rc = PTR_ERR(cxlflash_class);
+ pr_err("%s: class_create failed rc=%d\n", __func__, rc);
+ goto err;
+ }
+
+ cxlflash_class->devnode = cxlflash_devnode;
+out:
+ pr_debug("%s: returning rc=%d\n", __func__, rc);
+ return rc;
+err:
+ unregister_chrdev_region(devno, CXLFLASH_MAX_ADAPTERS);
+ goto out;
+}
+
+/**
+ * cxlflash_class_exit() - destroy character device class
+ */
+static void cxlflash_class_exit(void)
+{
+ dev_t devno = MKDEV(cxlflash_major, 0);
+
+ class_destroy(cxlflash_class);
+ unregister_chrdev_region(devno, CXLFLASH_MAX_ADAPTERS);
+}
+
static const struct pci_error_handlers cxlflash_err_handler = {
.error_detected = cxlflash_pci_error_detected,
.slot_reset = cxlflash_pci_slot_reset,
@@ -3356,10 +3547,23 @@ static struct pci_driver cxlflash_driver = {
*/
static int __init init_cxlflash(void)
{
+ int rc;
+
check_sizes();
cxlflash_list_init();
+ rc = cxlflash_class_init();
+ if (unlikely(rc))
+ goto out;
- return pci_register_driver(&cxlflash_driver);
+ rc = pci_register_driver(&cxlflash_driver);
+ if (unlikely(rc))
+ goto err;
+out:
+ pr_debug("%s: returning rc=%d\n", __func__, rc);
+ return rc;
+err:
+ cxlflash_class_exit();
+ goto out;
}
/**
@@ -3371,6 +3575,7 @@ static void __exit exit_cxlflash(void)
cxlflash_free_errpage();
pci_unregister_driver(&cxlflash_driver);
+ cxlflash_class_exit();
}
module_init(init_cxlflash);
diff --git a/drivers/scsi/cxlflash/main.h b/drivers/scsi/cxlflash/main.h
index 49657f1..44c86c2 100644
--- a/drivers/scsi/cxlflash/main.h
+++ b/drivers/scsi/cxlflash/main.h
@@ -22,6 +22,7 @@
#define CXLFLASH_NAME "cxlflash"
#define CXLFLASH_ADAPTER_NAME "IBM POWER CXL Flash Adapter"
+#define CXLFLASH_MAX_ADAPTERS 32
#define PCI_DEVICE_ID_IBM_CORSA 0x04F0
#define PCI_DEVICE_ID_IBM_FLASH_GT 0x0600
--
2.1.0
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