cxl: Introduce implementation-specific API

The backend API (in cxl.h) lists some low-level functions whose
implementation is different on bare-metal and in a guest. Each
environment implements its own functions, and the common code uses
them through function pointers, defined in cxl_backend_ops

Co-authored-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Reviewed-by: Manoj Kumar <manoj@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

drivers/misc/cxl/api.c

@@ -100,7 +100,7 @@ EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
 void cxl_free_afu_irqs(struct cxl_context *ctx)
 {
 	afu_irq_name_free(ctx);
-	cxl_release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
+	cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
 }
 EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
 
@@ -176,7 +176,7 @@ int cxl_start_context(struct cxl_context *ctx, u64 wed,
 
 	cxl_ctx_get();
 
-	if ((rc = cxl_attach_process(ctx, kernel, wed , 0))) {
+	if ((rc = cxl_ops->attach_process(ctx, kernel, wed, 0))) {
 		put_pid(ctx->pid);
 		cxl_ctx_put();
 		goto out;
@@ -342,11 +342,11 @@ int cxl_afu_reset(struct cxl_context *ctx)
 	struct cxl_afu *afu = ctx->afu;
 	int rc;
 
-	rc = __cxl_afu_reset(afu);
+	rc = cxl_ops->afu_reset(afu);
 	if (rc)
 		return rc;
 
-	return cxl_afu_check_and_enable(afu);
+	return cxl_ops->afu_check_and_enable(afu);
 }
 EXPORT_SYMBOL_GPL(cxl_afu_reset);
 

drivers/misc/cxl/context.c

@@ -214,8 +214,8 @@ int __detach_context(struct cxl_context *ctx)
 	/* Only warn if we detached while the link was OK.
 	 * If detach fails when hw is down, we don't care.
 	 */
-	WARN_ON(cxl_detach_process(ctx) &&
-		cxl_adapter_link_ok(ctx->afu->adapter));
+	WARN_ON(cxl_ops->detach_process(ctx) &&
+		cxl_ops->link_ok(ctx->afu->adapter));
 	flush_work(&ctx->fault_work); /* Only needed for dedicated process */
 
 	/* release the reference to the group leader and mm handling pid */

drivers/misc/cxl/cxl.h

@@ -623,11 +623,6 @@ static inline u64 cxl_p2n_read(struct cxl_afu *afu, cxl_p2n_reg_t reg)
 		return ~0ULL;
 }
 
-u64 cxl_afu_cr_read64(struct cxl_afu *afu, int cr, u64 off);
-u32 cxl_afu_cr_read32(struct cxl_afu *afu, int cr, u64 off);
-u16 cxl_afu_cr_read16(struct cxl_afu *afu, int cr, u64 off);
-u8 cxl_afu_cr_read8(struct cxl_afu *afu, int cr, u64 off);
-
 ssize_t cxl_afu_read_err_buffer(struct cxl_afu *afu, char *buf,
 				loff_t off, size_t count);
 
@@ -666,10 +661,6 @@ void cxl_sysfs_afu_m_remove(struct cxl_afu *afu);
 
 struct cxl *cxl_alloc_adapter(void);
 struct cxl_afu *cxl_alloc_afu(struct cxl *adapter, int slice);
-
-int cxl_afu_activate_mode(struct cxl_afu *afu, int mode);
-int _cxl_afu_deactivate_mode(struct cxl_afu *afu, int mode);
-int cxl_afu_deactivate_mode(struct cxl_afu *afu);
 int cxl_afu_select_best_mode(struct cxl_afu *afu);
 
 int cxl_register_psl_irq(struct cxl_afu *afu);
@@ -681,8 +672,6 @@ void cxl_release_serr_irq(struct cxl_afu *afu);
 int afu_register_irqs(struct cxl_context *ctx, u32 count);
 void afu_release_irqs(struct cxl_context *ctx, void *cookie);
 void afu_irq_name_free(struct cxl_context *ctx);
-irqreturn_t handle_psl_slice_error(struct cxl_context *ctx, u64 dsisr,
-				u64 errstat);
 
 int cxl_debugfs_init(void);
 void cxl_debugfs_exit(void);
@@ -727,18 +716,10 @@ int cxl_register_one_irq(struct cxl *adapter, irq_handler_t handler,
 			void *cookie, irq_hw_number_t *dest_hwirq,
 			unsigned int *dest_virq, const char *name);
 
-int cxl_attach_process(struct cxl_context *ctx, bool kernel, u64 wed,
-			    u64 amr);
-int cxl_detach_process(struct cxl_context *ctx);
-
-int cxl_ack_irq(struct cxl_context *ctx, u64 tfc, u64 psl_reset_mask);
-
 int cxl_check_error(struct cxl_afu *afu);
 int cxl_afu_slbia(struct cxl_afu *afu);
 int cxl_tlb_slb_invalidate(struct cxl *adapter);
 int cxl_afu_disable(struct cxl_afu *afu);
-int __cxl_afu_reset(struct cxl_afu *afu);
-int cxl_afu_check_and_enable(struct cxl_afu *afu);
 int cxl_psl_purge(struct cxl_afu *afu);
 
 void cxl_stop_trace(struct cxl *cxl);
@@ -757,4 +738,38 @@ unsigned int afu_poll(struct file *file, struct poll_table_struct *poll);
 ssize_t afu_read(struct file *file, char __user *buf, size_t count, loff_t *off);
 extern const struct file_operations afu_fops;
 
+struct cxl_backend_ops {
+	struct module *module;
+	int (*adapter_reset)(struct cxl *adapter);
+	int (*alloc_one_irq)(struct cxl *adapter);
+	void (*release_one_irq)(struct cxl *adapter, int hwirq);
+	int (*alloc_irq_ranges)(struct cxl_irq_ranges *irqs,
+				struct cxl *adapter, unsigned int num);
+	void (*release_irq_ranges)(struct cxl_irq_ranges *irqs,
+				struct cxl *adapter);
+	int (*setup_irq)(struct cxl *adapter, unsigned int hwirq,
+			unsigned int virq);
+	irqreturn_t (*handle_psl_slice_error)(struct cxl_context *ctx,
+					u64 dsisr, u64 errstat);
+	irqreturn_t (*psl_interrupt)(int irq, void *data);
+	int (*ack_irq)(struct cxl_context *ctx, u64 tfc, u64 psl_reset_mask);
+	int (*attach_process)(struct cxl_context *ctx, bool kernel,
+			u64 wed, u64 amr);
+	int (*detach_process)(struct cxl_context *ctx);
+	bool (*link_ok)(struct cxl *cxl);
+	void (*release_afu)(struct device *dev);
+	ssize_t (*afu_read_err_buffer)(struct cxl_afu *afu, char *buf,
+				loff_t off, size_t count);
+	int (*afu_check_and_enable)(struct cxl_afu *afu);
+	int (*afu_activate_mode)(struct cxl_afu *afu, int mode);
+	int (*afu_deactivate_mode)(struct cxl_afu *afu, int mode);
+	int (*afu_reset)(struct cxl_afu *afu);
+	int (*afu_cr_read8)(struct cxl_afu *afu, int cr_idx, u64 offset, u8 *val);
+	int (*afu_cr_read16)(struct cxl_afu *afu, int cr_idx, u64 offset, u16 *val);
+	int (*afu_cr_read32)(struct cxl_afu *afu, int cr_idx, u64 offset, u32 *val);
+	int (*afu_cr_read64)(struct cxl_afu *afu, int cr_idx, u64 offset, u64 *val);
+};
+extern const struct cxl_backend_ops cxl_native_ops;
+extern const struct cxl_backend_ops *cxl_ops;
+
 #endif

drivers/misc/cxl/fault.c

@@ -101,7 +101,7 @@ static void cxl_ack_ae(struct cxl_context *ctx)
 {
 	unsigned long flags;
 
-	cxl_ack_irq(ctx, CXL_PSL_TFC_An_AE, 0);
+	cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_AE, 0);
 
 	spin_lock_irqsave(&ctx->lock, flags);
 	ctx->pending_fault = true;
@@ -125,7 +125,7 @@ static int cxl_handle_segment_miss(struct cxl_context *ctx,
 	else {
 
 		mb(); /* Order seg table write to TFC MMIO write */
-		cxl_ack_irq(ctx, CXL_PSL_TFC_An_R, 0);
+		cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_R, 0);
 	}
 
 	return IRQ_HANDLED;
@@ -163,7 +163,7 @@ static void cxl_handle_page_fault(struct cxl_context *ctx,
 	local_irq_restore(flags);
 
 	pr_devel("Page fault successfully handled for pe: %i!\n", ctx->pe);
-	cxl_ack_irq(ctx, CXL_PSL_TFC_An_R, 0);
+	cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_R, 0);
 }
 
 /*

drivers/misc/cxl/file.c

@@ -79,7 +79,7 @@ static int __afu_open(struct inode *inode, struct file *file, bool master)
 	if (!afu->current_mode)
 		goto err_put_afu;
 
-	if (!cxl_adapter_link_ok(adapter)) {
+	if (!cxl_ops->link_ok(adapter)) {
 		rc = -EIO;
 		goto err_put_afu;
 	}
@@ -210,8 +210,8 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
 
 	trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr);
 
-	if ((rc = cxl_attach_process(ctx, false, work.work_element_descriptor,
-				     amr))) {
+	if ((rc = cxl_ops->attach_process(ctx, false, work.work_element_descriptor,
+							amr))) {
 		afu_release_irqs(ctx, ctx);
 		goto out;
 	}
@@ -222,6 +222,7 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
 	mutex_unlock(&ctx->status_mutex);
 	return rc;
 }
+
 static long afu_ioctl_process_element(struct cxl_context *ctx,
 				      int __user *upe)
 {
@@ -259,7 +260,7 @@ long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	if (ctx->status == CLOSED)
 		return -EIO;
 
-	if (!cxl_adapter_link_ok(ctx->afu->adapter))
+	if (!cxl_ops->link_ok(ctx->afu->adapter))
 		return -EIO;
 
 	pr_devel("afu_ioctl\n");
@@ -289,7 +290,7 @@ int afu_mmap(struct file *file, struct vm_area_struct *vm)
 	if (ctx->status != STARTED)
 		return -EIO;
 
-	if (!cxl_adapter_link_ok(ctx->afu->adapter))
+	if (!cxl_ops->link_ok(ctx->afu->adapter))
 		return -EIO;
 
 	return cxl_context_iomap(ctx, vm);
@@ -336,7 +337,7 @@ ssize_t afu_read(struct file *file, char __user *buf, size_t count,
 	int rc;
 	DEFINE_WAIT(wait);
 
-	if (!cxl_adapter_link_ok(ctx->afu->adapter))
+	if (!cxl_ops->link_ok(ctx->afu->adapter))
 		return -EIO;
 
 	if (count < CXL_READ_MIN_SIZE)
@@ -349,7 +350,7 @@ ssize_t afu_read(struct file *file, char __user *buf, size_t count,
 		if (ctx_event_pending(ctx))
 			break;
 
-		if (!cxl_adapter_link_ok(ctx->afu->adapter)) {
+		if (!cxl_ops->link_ok(ctx->afu->adapter)) {
 			rc = -EIO;
 			goto out;
 		}

drivers/misc/cxl/irq.c

@@ -79,7 +79,8 @@ irqreturn_t cxl_irq(int irq, void *data, struct cxl_irq_info *irq_info)
 	if (dsisr & CXL_PSL_DSISR_An_UR)
 		pr_devel("CXL interrupt: AURP PTE not found\n");
 	if (dsisr & CXL_PSL_DSISR_An_PE)
-		return handle_psl_slice_error(ctx, dsisr, irq_info->errstat);
+		return cxl_ops->handle_psl_slice_error(ctx, dsisr,
+						irq_info->errstat);
 	if (dsisr & CXL_PSL_DSISR_An_AE) {
 		pr_devel("CXL interrupt: AFU Error 0x%016llx\n", irq_info->afu_err);
 
@@ -103,7 +104,7 @@ irqreturn_t cxl_irq(int irq, void *data, struct cxl_irq_info *irq_info)
 			wake_up_all(&ctx->wq);
 		}
 
-		cxl_ack_irq(ctx, CXL_PSL_TFC_An_A, 0);
+		cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_A, 0);
 		return IRQ_HANDLED;
 	}
 	if (dsisr & CXL_PSL_DSISR_An_OC)
@@ -167,7 +168,8 @@ unsigned int cxl_map_irq(struct cxl *adapter, irq_hw_number_t hwirq,
 		return 0;
 	}
 
-	cxl_setup_irq(adapter, hwirq, virq);
+	if (cxl_ops->setup_irq)
+		cxl_ops->setup_irq(adapter, hwirq, virq);
 
 	pr_devel("hwirq %#lx mapped to virq %u\n", hwirq, virq);
 
@@ -195,7 +197,7 @@ int cxl_register_one_irq(struct cxl *adapter,
 {
 	int hwirq, virq;
 
-	if ((hwirq = cxl_alloc_one_irq(adapter)) < 0)
+	if ((hwirq = cxl_ops->alloc_one_irq(adapter)) < 0)
 		return hwirq;
 
 	if (!(virq = cxl_map_irq(adapter, hwirq, handler, cookie, name)))
@@ -207,7 +209,7 @@ int cxl_register_one_irq(struct cxl *adapter,
 	return 0;
 
 err:
-	cxl_release_one_irq(adapter, hwirq);
+	cxl_ops->release_one_irq(adapter, hwirq);
 	return -ENOMEM;
 }
 
@@ -230,7 +232,8 @@ int afu_allocate_irqs(struct cxl_context *ctx, u32 count)
 	/* Initialize the list head to hold irq names */
 	INIT_LIST_HEAD(&ctx->irq_names);
 
-	if ((rc = cxl_alloc_irq_ranges(&ctx->irqs, ctx->afu->adapter, count)))
+	if ((rc = cxl_ops->alloc_irq_ranges(&ctx->irqs, ctx->afu->adapter,
+							count)))
 		return rc;
 
 	/* Multiplexed PSL Interrupt */
@@ -268,7 +271,7 @@ int afu_allocate_irqs(struct cxl_context *ctx, u32 count)
 	return 0;
 
 out:
-	cxl_release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
+	cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
 	afu_irq_name_free(ctx);
 	return -ENOMEM;
 }
@@ -319,7 +322,7 @@ void afu_release_irqs(struct cxl_context *ctx, void *cookie)
 	}
 
 	afu_irq_name_free(ctx);
-	cxl_release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
+	cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
 
 	ctx->irq_count = 0;
 }

drivers/misc/cxl/main.c

@@ -32,6 +32,8 @@ uint cxl_verbose;
 module_param_named(verbose, cxl_verbose, uint, 0600);
 MODULE_PARM_DESC(verbose, "Enable verbose dmesg output");
 
+const struct cxl_backend_ops *cxl_ops;
+
 int cxl_afu_slbia(struct cxl_afu *afu)
 {
 	unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT);
@@ -46,7 +48,7 @@ int cxl_afu_slbia(struct cxl_afu *afu)
 		/* If the adapter has gone down, we can assume that we
 		 * will PERST it and that will invalidate everything.
 		 */
-		if (!cxl_adapter_link_ok(afu->adapter))
+		if (!cxl_ops->link_ok(afu->adapter))
 			return -EIO;
 		cpu_relax();
 	}
@@ -228,7 +230,7 @@ struct cxl_afu *cxl_alloc_afu(struct cxl *adapter, int slice)
 
 	afu->adapter = adapter;
 	afu->dev.parent = &adapter->dev;
-	afu->dev.release = cxl_release_afu;
+	afu->dev.release = cxl_ops->release_afu;
 	afu->slice = slice;
 	idr_init(&afu->contexts_idr);
 	mutex_init(&afu->contexts_lock);
@@ -244,10 +246,10 @@ struct cxl_afu *cxl_alloc_afu(struct cxl *adapter, int slice)
 int cxl_afu_select_best_mode(struct cxl_afu *afu)
 {
 	if (afu->modes_supported & CXL_MODE_DIRECTED)
-		return cxl_afu_activate_mode(afu, CXL_MODE_DIRECTED);
+		return cxl_ops->afu_activate_mode(afu, CXL_MODE_DIRECTED);
 
 	if (afu->modes_supported & CXL_MODE_DEDICATED)
-		return cxl_afu_activate_mode(afu, CXL_MODE_DEDICATED);
+		return cxl_ops->afu_activate_mode(afu, CXL_MODE_DEDICATED);
 
 	dev_warn(&afu->dev, "No supported programming modes available\n");
 	/* We don't fail this so the user can inspect sysfs */
@@ -269,6 +271,7 @@ static int __init init_cxl(void)
 	if ((rc = register_cxl_calls(&cxl_calls)))
 		goto err;
 
+	cxl_ops = &cxl_native_ops;
 	if ((rc = pci_register_driver(&cxl_pci_driver)))
 		goto err1;