scsi: cxlflash: Support AFU debug

Adopt the SISLite AFU debug capability to allow future CXL Flash
adapters the ability to better debug AFU issues. Update the SISLite
header with the changes necessary to support AFU debug operations
and create a host ioctl interface for user debug software. Also
update the cxlflash documentation to describe this new host ioctl.

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>

1 files changed, 96 insertions, 0 deletions

diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 1279293ff3b3..d3ad52ec5314 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -3326,6 +3326,99 @@ out:
 }
 
 /**
+ * cxlflash_afu_debug() - host AFU debug handler
+ * @cfg:	Internal structure associated with the host.
+ * @arg:	Kernel copy of userspace ioctl data structure.
+ *
+ * For debug requests requiring a data buffer, always provide an aligned
+ * (cache line) buffer to the AFU to appease any alignment requirements.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int cxlflash_afu_debug(struct cxlflash_cfg *cfg,
+			      struct ht_cxlflash_afu_debug *afu_dbg)
+{
+	struct afu *afu = cfg->afu;
+	struct device *dev = &cfg->dev->dev;
+	struct sisl_ioarcb rcb;
+	struct sisl_ioasa asa;
+	char *buf = NULL;
+	char *kbuf = NULL;
+	void __user *ubuf = (__force void __user *)afu_dbg->data_ea;
+	u16 req_flags = SISL_REQ_FLAGS_AFU_CMD;
+	u32 ulen = afu_dbg->data_len;
+	bool is_write = afu_dbg->hdr.flags & HT_CXLFLASH_HOST_WRITE;
+	int rc = 0;
+
+	if (!afu_is_afu_debug(afu)) {
+		rc = -ENOTSUPP;
+		goto out;
+	}
+
+	if (ulen) {
+		req_flags |= SISL_REQ_FLAGS_SUP_UNDERRUN;
+
+		if (ulen > HT_CXLFLASH_AFU_DEBUG_MAX_DATA_LEN) {
+			rc = -EINVAL;
+			goto out;
+		}
+
+		if (unlikely(!access_ok(is_write ? VERIFY_READ : VERIFY_WRITE,
+					ubuf, ulen))) {
+			rc = -EFAULT;
+			goto out;
+		}
+
+		buf = kmalloc(ulen + cache_line_size() - 1, GFP_KERNEL);
+		if (unlikely(!buf)) {
+			rc = -ENOMEM;
+			goto out;
+		}
+
+		kbuf = PTR_ALIGN(buf, cache_line_size());
+
+		if (is_write) {
+			req_flags |= SISL_REQ_FLAGS_HOST_WRITE;
+
+			rc = copy_from_user(kbuf, ubuf, ulen);
+			if (unlikely(rc))
+				goto out;
+		}
+	}
+
+	memset(&rcb, 0, sizeof(rcb));
+	memset(&asa, 0, sizeof(asa));
+
+	rcb.req_flags = req_flags;
+	rcb.msi = SISL_MSI_RRQ_UPDATED;
+	rcb.timeout = MC_AFU_DEBUG_TIMEOUT;
+	rcb.ioasa = &asa;
+
+	if (ulen) {
+		rcb.data_len = ulen;
+		rcb.data_ea = (uintptr_t)kbuf;
+	}
+
+	rcb.cdb[0] = SISL_AFU_CMD_DEBUG;
+	memcpy(&rcb.cdb[4], afu_dbg->afu_subcmd,
+	       HT_CXLFLASH_AFU_DEBUG_SUBCMD_LEN);
+
+	rc = send_afu_cmd(afu, &rcb);
+	if (rc) {
+		dev_err(dev, "%s: send_afu_cmd failed rc=%d asc=%08x afux=%x\n",
+			__func__, rc, asa.ioasc, asa.afu_extra);
+		goto out;
+	}
+
+	if (ulen && !is_write)
+		rc = copy_to_user(ubuf, kbuf, ulen);
+out:
+	kfree(buf);
+	dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
+	return rc;
+}
+
+/**
  * cxlflash_chr_ioctl() - character device IOCTL handler
  * @file:	File pointer for this device.
  * @cmd:	IOCTL command.
@@ -3363,6 +3456,8 @@ static long cxlflash_chr_ioctl(struct file *file, unsigned int cmd,
 	} ioctl_tbl[] = {	/* NOTE: order matters here */
 	{ sizeof(struct ht_cxlflash_lun_provision),
 		(hioctl)cxlflash_lun_provision },
+	{ sizeof(struct ht_cxlflash_afu_debug),
+		(hioctl)cxlflash_afu_debug },
 	};
 
 	/* Hold read semaphore so we can drain if needed */
@@ -3373,6 +3468,7 @@ static long cxlflash_chr_ioctl(struct file *file, unsigned int cmd,
 
 	switch (cmd) {
 	case HT_CXLFLASH_LUN_PROVISION:
+	case HT_CXLFLASH_AFU_DEBUG:
 		known_ioctl = true;
 		idx = _IOC_NR(HT_CXLFLASH_LUN_PROVISION) - _IOC_NR(cmd);
 		size = ioctl_tbl[idx].size;