scsi: cxlflash: Staging to support future accelerators

As staging to support future accelerator transports, add a shim layer
such that the underlying services the cxlflash driver requires can be
conditional upon the accelerator infrastructure.

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>

drivers/scsi/cxlflash/Makefile

@@ -1,2 +1,2 @@
 obj-$(CONFIG_CXLFLASH) += cxlflash.o
-cxlflash-y += main.o superpipe.o lunmgt.o vlun.o
+cxlflash-y += main.o superpipe.o lunmgt.o vlun.o cxl_hw.o

drivers/scsi/cxlflash/backend.h

@@ -0,0 +1,41 @@
+/*
+ * CXL Flash Device Driver
+ *
+ * Written by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
+ *             Uma Krishnan <ukrishn@linux.vnet.ibm.com>, IBM Corporation
+ *
+ * Copyright (C) 2018 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.
+ */
+
+extern const struct cxlflash_backend_ops cxlflash_cxl_ops;
+
+struct cxlflash_backend_ops {
+	struct module *module;
+	void __iomem * (*psa_map)(void *);
+	void (*psa_unmap)(void __iomem *);
+	int (*process_element)(void *);
+	int (*map_afu_irq)(void *, int, irq_handler_t, void *, char *);
+	void (*unmap_afu_irq)(void *, int, void *);
+	int (*start_context)(void *);
+	int (*stop_context)(void *);
+	int (*afu_reset)(void *);
+	void (*set_master)(void *);
+	void * (*get_context)(struct pci_dev *, void *);
+	void * (*dev_context_init)(struct pci_dev *, void *);
+	int (*release_context)(void *);
+	void (*perst_reloads_same_image)(void *, bool);
+	ssize_t (*read_adapter_vpd)(struct pci_dev *, void *, size_t);
+	int (*allocate_afu_irqs)(void *, int);
+	void (*free_afu_irqs)(void *);
+	void * (*create_afu)(struct pci_dev *);
+	struct file * (*get_fd)(void *, struct file_operations *, int *);
+	void * (*fops_get_context)(struct file *);
+	int (*start_work)(void *, u64);
+	int (*fd_mmap)(struct file *, struct vm_area_struct *);
+	int (*fd_release)(struct inode *, struct file *);
+};

drivers/scsi/cxlflash/common.h

@@ -25,6 +25,8 @@
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_device.h>
 
+#include "backend.h"
+
 extern const struct file_operations cxlflash_cxl_fops;
 
 #define MAX_CONTEXT	CXLFLASH_MAX_CONTEXT	/* num contexts per afu */
@@ -114,6 +116,7 @@ enum cxlflash_hwq_mode {
 struct cxlflash_cfg {
 	struct afu *afu;
 
+	const struct cxlflash_backend_ops *ops;
 	struct pci_dev *dev;
 	struct pci_device_id *dev_id;
 	struct Scsi_Host *host;

drivers/scsi/cxlflash/cxl_hw.c

@@ -0,0 +1,168 @@
+/*
+ * CXL Flash Device Driver
+ *
+ * Written by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
+ *             Uma Krishnan <ukrishn@linux.vnet.ibm.com>, IBM Corporation
+ *
+ * Copyright (C) 2018 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.
+ */
+
+#include <misc/cxl.h>
+
+#include "backend.h"
+
+/*
+ * The following routines map the cxlflash backend operations to existing CXL
+ * kernel API function and are largely simple shims that provide an abstraction
+ * for converting generic context and AFU cookies into cxl_context or cxl_afu
+ * pointers.
+ */
+
+static void __iomem *cxlflash_psa_map(void *ctx_cookie)
+{
+	return cxl_psa_map(ctx_cookie);
+}
+
+static void cxlflash_psa_unmap(void __iomem *addr)
+{
+	cxl_psa_unmap(addr);
+}
+
+static int cxlflash_process_element(void *ctx_cookie)
+{
+	return cxl_process_element(ctx_cookie);
+}
+
+static int cxlflash_map_afu_irq(void *ctx_cookie, int num,
+				irq_handler_t handler, void *cookie, char *name)
+{
+	return cxl_map_afu_irq(ctx_cookie, num, handler, cookie, name);
+}
+
+static void cxlflash_unmap_afu_irq(void *ctx_cookie, int num, void *cookie)
+{
+	cxl_unmap_afu_irq(ctx_cookie, num, cookie);
+}
+
+static int cxlflash_start_context(void *ctx_cookie)
+{
+	return cxl_start_context(ctx_cookie, 0, NULL);
+}
+
+static int cxlflash_stop_context(void *ctx_cookie)
+{
+	return cxl_stop_context(ctx_cookie);
+}
+
+static int cxlflash_afu_reset(void *ctx_cookie)
+{
+	return cxl_afu_reset(ctx_cookie);
+}
+
+static void cxlflash_set_master(void *ctx_cookie)
+{
+	cxl_set_master(ctx_cookie);
+}
+
+static void *cxlflash_get_context(struct pci_dev *dev, void *afu_cookie)
+{
+	return cxl_get_context(dev);
+}
+
+static void *cxlflash_dev_context_init(struct pci_dev *dev, void *afu_cookie)
+{
+	return cxl_dev_context_init(dev);
+}
+
+static int cxlflash_release_context(void *ctx_cookie)
+{
+	return cxl_release_context(ctx_cookie);
+}
+
+static void cxlflash_perst_reloads_same_image(void *afu_cookie, bool image)
+{
+	cxl_perst_reloads_same_image(afu_cookie, image);
+}
+
+static ssize_t cxlflash_read_adapter_vpd(struct pci_dev *dev,
+					 void *buf, size_t count)
+{
+	return cxl_read_adapter_vpd(dev, buf, count);
+}
+
+static int cxlflash_allocate_afu_irqs(void *ctx_cookie, int num)
+{
+	return cxl_allocate_afu_irqs(ctx_cookie, num);
+}
+
+static void cxlflash_free_afu_irqs(void *ctx_cookie)
+{
+	cxl_free_afu_irqs(ctx_cookie);
+}
+
+static void *cxlflash_create_afu(struct pci_dev *dev)
+{
+	return cxl_pci_to_afu(dev);
+}
+
+static struct file *cxlflash_get_fd(void *ctx_cookie,
+				    struct file_operations *fops, int *fd)
+{
+	return cxl_get_fd(ctx_cookie, fops, fd);
+}
+
+static void *cxlflash_fops_get_context(struct file *file)
+{
+	return cxl_fops_get_context(file);
+}
+
+static int cxlflash_start_work(void *ctx_cookie, u64 irqs)
+{
+	struct cxl_ioctl_start_work work = { 0 };
+
+	work.num_interrupts = irqs;
+	work.flags = CXL_START_WORK_NUM_IRQS;
+
+	return cxl_start_work(ctx_cookie, &work);
+}
+
+static int cxlflash_fd_mmap(struct file *file, struct vm_area_struct *vm)
+{
+	return cxl_fd_mmap(file, vm);
+}
+
+static int cxlflash_fd_release(struct inode *inode, struct file *file)
+{
+	return cxl_fd_release(inode, file);
+}
+
+const struct cxlflash_backend_ops cxlflash_cxl_ops = {
+	.module			= THIS_MODULE,
+	.psa_map		= cxlflash_psa_map,
+	.psa_unmap		= cxlflash_psa_unmap,
+	.process_element	= cxlflash_process_element,
+	.map_afu_irq		= cxlflash_map_afu_irq,
+	.unmap_afu_irq		= cxlflash_unmap_afu_irq,
+	.start_context		= cxlflash_start_context,
+	.stop_context		= cxlflash_stop_context,
+	.afu_reset		= cxlflash_afu_reset,
+	.set_master		= cxlflash_set_master,
+	.get_context		= cxlflash_get_context,
+	.dev_context_init	= cxlflash_dev_context_init,
+	.release_context	= cxlflash_release_context,
+	.perst_reloads_same_image = cxlflash_perst_reloads_same_image,
+	.read_adapter_vpd	= cxlflash_read_adapter_vpd,
+	.allocate_afu_irqs	= cxlflash_allocate_afu_irqs,
+	.free_afu_irqs		= cxlflash_free_afu_irqs,
+	.create_afu		= cxlflash_create_afu,
+	.get_fd			= cxlflash_get_fd,
+	.fops_get_context	= cxlflash_fops_get_context,
+	.start_work		= cxlflash_start_work,
+	.fd_mmap		= cxlflash_fd_mmap,
+	.fd_release		= cxlflash_fd_release,
+};