scsi: cxlflash: Introduce host ioctl support
As staging for supporting various host management functions, add a host ioctl infrastructure to filter ioctl commands and perform operations that are common for all host ioctls. Also update the cxlflash documentation to create a new section for documenting host ioctls. Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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@ -326,7 +326,7 @@ Code Seq#(hex) Include File Comments
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0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
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0xC0 00-0F linux/usb/iowarrior.h
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0xCA 00-0F uapi/misc/cxl.h
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0xCA 80-8F uapi/scsi/cxlflash_ioctl.h
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0xCA 80-BF uapi/scsi/cxlflash_ioctl.h
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0xCB 00-1F CBM serial IEC bus in development:
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<mailto:michael.klein@puffin.lb.shuttle.de>
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0xCD 01 linux/reiserfs_fs.h
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@ -124,8 +124,8 @@ Block library API
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http://github.com/open-power/capiflash
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CXL Flash Driver IOCTLs
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=======================
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CXL Flash Driver LUN IOCTLs
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===========================
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Users, such as the block library, that wish to interface with a flash
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device (LUN) via user space access need to use the services provided
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@ -367,3 +367,18 @@ DK_CXLFLASH_MANAGE_LUN
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exclusive user space access (superpipe). In case a LUN is visible
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across multiple ports and adapters, this ioctl is used to uniquely
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identify each LUN by its World Wide Node Name (WWNN).
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CXL Flash Driver Host IOCTLs
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============================
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Each host adapter instance that is supported by the cxlflash driver
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has a special character device associated with it to enable a set of
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host management function. These character devices are hosted in a
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class dedicated for cxlflash and can be accessed via /dev/cxlflash/*.
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Applications can be written to perform various functions using the
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host ioctl APIs below.
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The structure definitions for these IOCTLs are available in:
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uapi/scsi/cxlflash_ioctl.h
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@ -2693,7 +2693,14 @@ static ssize_t lun_mode_store(struct device *dev,
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static ssize_t ioctl_version_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return scnprintf(buf, PAGE_SIZE, "%u\n", DK_CXLFLASH_VERSION_0);
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ssize_t bytes = 0;
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bytes = scnprintf(buf, PAGE_SIZE,
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"disk: %u\n", DK_CXLFLASH_VERSION_0);
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bytes += scnprintf(buf + bytes, PAGE_SIZE - bytes,
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"host: %u\n", HT_CXLFLASH_VERSION_0);
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return bytes;
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}
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/**
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@ -3211,12 +3218,124 @@ static int cxlflash_chr_open(struct inode *inode, struct file *file)
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return 0;
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}
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/**
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* decode_hioctl() - translates encoded host ioctl to easily identifiable string
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* @cmd: The host ioctl command to decode.
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*
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* Return: A string identifying the decoded host ioctl.
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*/
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static char *decode_hioctl(int cmd)
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{
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switch (cmd) {
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default:
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return "UNKNOWN";
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}
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return "UNKNOWN";
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}
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/**
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* cxlflash_chr_ioctl() - character device IOCTL handler
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* @file: File pointer for this device.
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* @cmd: IOCTL command.
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* @arg: Userspace ioctl data structure.
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*
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* A read/write semaphore is used to implement a 'drain' of currently
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* running ioctls. The read semaphore is taken at the beginning of each
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* ioctl thread and released upon concluding execution. Additionally the
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* semaphore should be released and then reacquired in any ioctl execution
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* path which will wait for an event to occur that is outside the scope of
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* the ioctl (i.e. an adapter reset). To drain the ioctls currently running,
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* a thread simply needs to acquire the write semaphore.
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*
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* Return: 0 on success, -errno on failure
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*/
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static long cxlflash_chr_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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typedef int (*hioctl) (struct cxlflash_cfg *, void *);
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struct cxlflash_cfg *cfg = file->private_data;
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struct device *dev = &cfg->dev->dev;
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char buf[sizeof(union cxlflash_ht_ioctls)];
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void __user *uarg = (void __user *)arg;
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struct ht_cxlflash_hdr *hdr;
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size_t size = 0;
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bool known_ioctl = false;
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int idx = 0;
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int rc = 0;
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hioctl do_ioctl = NULL;
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static const struct {
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size_t size;
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hioctl ioctl;
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} ioctl_tbl[] = { /* NOTE: order matters here */
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};
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/* Hold read semaphore so we can drain if needed */
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down_read(&cfg->ioctl_rwsem);
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dev_dbg(dev, "%s: cmd=%u idx=%d tbl_size=%lu\n",
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__func__, cmd, idx, sizeof(ioctl_tbl));
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switch (cmd) {
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default:
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rc = -EINVAL;
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goto out;
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}
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if (unlikely(copy_from_user(&buf, uarg, size))) {
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dev_err(dev, "%s: copy_from_user() fail "
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"size=%lu cmd=%d (%s) uarg=%p\n",
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__func__, size, cmd, decode_hioctl(cmd), uarg);
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rc = -EFAULT;
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goto out;
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}
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hdr = (struct ht_cxlflash_hdr *)&buf;
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if (hdr->version != HT_CXLFLASH_VERSION_0) {
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dev_dbg(dev, "%s: Version %u not supported for %s\n",
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__func__, hdr->version, decode_hioctl(cmd));
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rc = -EINVAL;
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goto out;
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}
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if (hdr->rsvd[0] || hdr->rsvd[1] || hdr->return_flags) {
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dev_dbg(dev, "%s: Reserved/rflags populated\n", __func__);
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rc = -EINVAL;
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goto out;
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}
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rc = do_ioctl(cfg, (void *)&buf);
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if (likely(!rc))
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if (unlikely(copy_to_user(uarg, &buf, size))) {
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dev_err(dev, "%s: copy_to_user() fail "
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"size=%lu cmd=%d (%s) uarg=%p\n",
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__func__, size, cmd, decode_hioctl(cmd), uarg);
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rc = -EFAULT;
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}
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/* fall through to exit */
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out:
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up_read(&cfg->ioctl_rwsem);
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if (unlikely(rc && known_ioctl))
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dev_err(dev, "%s: ioctl %s (%08X) returned rc=%d\n",
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__func__, decode_hioctl(cmd), cmd, rc);
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else
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dev_dbg(dev, "%s: ioctl %s (%08X) returned rc=%d\n",
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__func__, decode_hioctl(cmd), cmd, rc);
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return rc;
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}
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/*
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* Character device file operations
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*/
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static const struct file_operations cxlflash_chr_fops = {
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.owner = THIS_MODULE,
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.open = cxlflash_chr_open,
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.unlocked_ioctl = cxlflash_chr_ioctl,
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.compat_ioctl = cxlflash_chr_ioctl,
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};
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/**
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@ -31,7 +31,7 @@ struct dk_cxlflash_hdr {
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};
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/*
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* Return flag definitions available to all ioctls
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* Return flag definitions available to all superpipe ioctls
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*
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* Similar to the input flags, these are grown from the bottom-up with the
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* intention that ioctl-specific return flag definitions would grow from the
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@ -180,6 +180,10 @@ union cxlflash_ioctls {
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#define CXL_MAGIC 0xCA
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#define CXL_IOWR(_n, _s) _IOWR(CXL_MAGIC, _n, struct _s)
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/*
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* CXL Flash superpipe ioctls start at base of the reserved CXL_MAGIC
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* region (0x80) and grow upwards.
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*/
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#define DK_CXLFLASH_ATTACH CXL_IOWR(0x80, dk_cxlflash_attach)
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#define DK_CXLFLASH_USER_DIRECT CXL_IOWR(0x81, dk_cxlflash_udirect)
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#define DK_CXLFLASH_RELEASE CXL_IOWR(0x82, dk_cxlflash_release)
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@ -191,4 +195,29 @@ union cxlflash_ioctls {
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#define DK_CXLFLASH_VLUN_RESIZE CXL_IOWR(0x88, dk_cxlflash_resize)
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#define DK_CXLFLASH_VLUN_CLONE CXL_IOWR(0x89, dk_cxlflash_clone)
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/*
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* Structure and flag definitions CXL Flash host ioctls
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*/
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#define HT_CXLFLASH_VERSION_0 0
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struct ht_cxlflash_hdr {
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__u16 version; /* Version data */
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__u16 subcmd; /* Sub-command */
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__u16 rsvd[2]; /* Reserved for future use */
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__u64 flags; /* Input flags */
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__u64 return_flags; /* Returned flags */
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};
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union cxlflash_ht_ioctls {
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};
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#define MAX_HT_CXLFLASH_IOCTL_SZ (sizeof(union cxlflash_ht_ioctls))
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/*
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* CXL Flash host ioctls start at the top of the reserved CXL_MAGIC
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* region (0xBF) and grow downwards.
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*/
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#endif /* ifndef _CXLFLASH_IOCTL_H */
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