cxlflash: Superpipe support

Add superpipe supporting infrastructure to device driver for the IBM CXL
Flash adapter. This patch allows userspace applications to take advantage
of the accelerated I/O features that this adapter provides and bypass the
traditional filesystem stack.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

1 files changed, 132 insertions, 0 deletions

diff --git a/drivers/scsi/cxlflash/superpipe.h b/drivers/scsi/cxlflash/superpipe.h
new file mode 100644
index 000000000000..ae39b9627118
--- /dev/null
+++ b/drivers/scsi/cxlflash/superpipe.h
@@ -0,0 +1,132 @@
+/*
+ * CXL Flash Device Driver
+ *
+ * Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
+ *             Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
+ *
+ * Copyright (C) 2015 IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _CXLFLASH_SUPERPIPE_H
+#define _CXLFLASH_SUPERPIPE_H
+
+extern struct cxlflash_global global;
+
+/*
+ * Terminology: use afu (and not adapter) to refer to the HW.
+ * Adapter is the entire slot and includes PSL out of which
+ * only the AFU is visible to user space.
+ */
+
+/* Chunk size parms: note sislite minimum chunk size is
+   0x10000 LBAs corresponding to a NMASK or 16.
+*/
+#define MC_CHUNK_SIZE     (1 << MC_RHT_NMASK)	/* in LBAs */
+
+#define MC_DISCOVERY_TIMEOUT 5  /* 5 secs */
+
+#define CHAN2PORT(_x)	((_x) + 1)
+
+enum lun_mode {
+	MODE_NONE = 0,
+	MODE_PHYSICAL
+};
+
+/* Global (entire driver, spans adapters) lun_info structure */
+struct glun_info {
+	u64 max_lba;		/* from read cap(16) */
+	u32 blk_len;		/* from read cap(16) */
+	enum lun_mode mode;	/* NONE, PHYSICAL */
+	int users;		/* Number of users w/ references to LUN */
+
+	u8 wwid[16];
+
+	struct mutex mutex;
+
+	struct list_head list;
+};
+
+/* Local (per-adapter) lun_info structure */
+struct llun_info {
+	u64 lun_id[CXLFLASH_NUM_FC_PORTS]; /* from REPORT_LUNS */
+	u32 lun_index;		/* Index in the LUN table */
+	u32 host_no;		/* host_no from Scsi_host */
+	u32 port_sel;		/* What port to use for this LUN */
+	bool newly_created;	/* Whether the LUN was just discovered */
+
+	u8 wwid[16];		/* Keep a duplicate copy here? */
+
+	struct glun_info *parent; /* Pointer to entry in global LUN structure */
+	struct scsi_device *sdev;
+	struct list_head list;
+};
+
+struct lun_access {
+	struct llun_info *lli;
+	struct scsi_device *sdev;
+	struct list_head list;
+};
+
+enum ctx_ctrl {
+	CTX_CTRL_CLONE		= (1 << 1),
+	CTX_CTRL_ERR		= (1 << 2),
+	CTX_CTRL_ERR_FALLBACK	= (1 << 3),
+	CTX_CTRL_NOPID		= (1 << 4),
+	CTX_CTRL_FILE		= (1 << 5)
+};
+
+#define ENCODE_CTXID(_ctx, _id)	(((((u64)_ctx) & 0xFFFFFFFF0) << 28) | _id)
+#define DECODE_CTXID(_val)	(_val & 0xFFFFFFFF)
+
+struct ctx_info {
+	struct sisl_ctrl_map *ctrl_map; /* initialized at startup */
+	struct sisl_rht_entry *rht_start; /* 1 page (req'd for alignment),
+					     alloc/free on attach/detach */
+	u32 rht_out;		/* Number of checked out RHT entries */
+	u32 rht_perms;		/* User-defined permissions for RHT entries */
+	struct llun_info **rht_lun;       /* Mapping of RHT entries to LUNs */
+
+	struct cxl_ioctl_start_work work;
+	u64 ctxid;
+	int lfd;
+	pid_t pid;
+	bool unavail;
+	bool err_recovery_active;
+	struct mutex mutex; /* Context protection */
+	struct cxl_context *ctx;
+	struct list_head luns;	/* LUNs attached to this context */
+	const struct vm_operations_struct *cxl_mmap_vmops;
+	struct file *file;
+	struct list_head list; /* Link contexts in error recovery */
+};
+
+struct cxlflash_global {
+	struct mutex mutex;
+	struct list_head gluns;/* list of glun_info structs */
+	struct page *err_page; /* One page of all 0xF for error notification */
+};
+
+int cxlflash_disk_release(struct scsi_device *, struct dk_cxlflash_release *);
+int _cxlflash_disk_release(struct scsi_device *, struct ctx_info *,
+			   struct dk_cxlflash_release *);
+
+int cxlflash_lun_attach(struct glun_info *, enum lun_mode, bool);
+void cxlflash_lun_detach(struct glun_info *);
+
+struct ctx_info *get_context(struct cxlflash_cfg *, u64, void *, enum ctx_ctrl);
+void put_context(struct ctx_info *);
+
+struct sisl_rht_entry *get_rhte(struct ctx_info *, res_hndl_t,
+				struct llun_info *);
+
+struct sisl_rht_entry *rhte_checkout(struct ctx_info *, struct llun_info *);
+void rhte_checkin(struct ctx_info *, struct sisl_rht_entry *);
+
+int cxlflash_manage_lun(struct scsi_device *, struct dk_cxlflash_manage_lun *);
+
+#endif /* ifndef _CXLFLASH_SUPERPIPE_H */