[v4,04/18] 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>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
---
 drivers/misc/cxl/api.c     |   8 +--
 drivers/misc/cxl/context.c |   4 +-
 drivers/misc/cxl/cxl.h     |  53 +++++++++++-------
 drivers/misc/cxl/fault.c   |   6 +-
 drivers/misc/cxl/file.c    |  15 ++---
 drivers/misc/cxl/irq.c     |  19 ++++---
 drivers/misc/cxl/main.c    |  11 ++--
 drivers/misc/cxl/native.c  | 135 ++++++++++++++++++++++++++++-----------------
 drivers/misc/cxl/pci.c     |  16 +++---
 drivers/misc/cxl/sysfs.c   |  32 +++++++----
 drivers/misc/cxl/vphb.c    |   6 +-
 11 files changed, 185 insertions(+), 120 deletions(-)

Reviewed-by: Manoj Kumar <manoj@linux.vnet.ibm.com>

---
Manoj Kumar

> Subject: [PATCH v4 04/18] cxl: Introduce implementation-specific API
> Date: Tue, 16 Feb 2016 22:38:57 +0100
> From: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
> To: imunsie@au1.ibm.com, michael.neuling@au1.ibm.com,
> mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org
>
> 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>
> Acked-by: Ian Munsie <imunsie@au1.ibm.com>
> ---
>   drivers/misc/cxl/api.c     |   8 +--
>   drivers/misc/cxl/context.c |   4 +-
>   drivers/misc/cxl/cxl.h     |  53 +++++++++++-------
>   drivers/misc/cxl/fault.c   |   6 +-
>   drivers/misc/cxl/file.c    |  15 ++---
>   drivers/misc/cxl/irq.c     |  19 ++++---
>   drivers/misc/cxl/main.c    |  11 ++--
>   drivers/misc/cxl/native.c  | 135
> ++++++++++++++++++++++++++++-----------------
>   drivers/misc/cxl/pci.c     |  16 +++---
>   drivers/misc/cxl/sysfs.c   |  32 +++++++----
>   drivers/misc/cxl/vphb.c    |   6 +-
>   11 files changed, 185 insertions(+), 120 deletions(-)
>
> diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
> index b45d857..31eb842 100644
> --- a/drivers/misc/cxl/api.c
> +++ b/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);
>
> diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
> index 262b88e..aa65262 100644
> --- a/drivers/misc/cxl/context.c
> +++ b/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 */
> diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
> index 3b824e3..8233af3 100644
> --- a/drivers/misc/cxl/cxl.h
> +++ b/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
> diff --git a/drivers/misc/cxl/fault.c b/drivers/misc/cxl/fault.c
> index 81c3f75..ab740a1 100644
> --- a/drivers/misc/cxl/fault.c
> +++ b/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);
>   }
>
>   /*
> diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
> index 783337d..b8ce29b 100644
> --- a/drivers/misc/cxl/file.c
> +++ b/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 @@ out:
>       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;
>           }
> diff --git a/drivers/misc/cxl/irq.c b/drivers/misc/cxl/irq.c
> index 16fd67f..56ad301 100644
> --- a/drivers/misc/cxl/irq.c
> +++ b/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;
>   }
> diff --git a/drivers/misc/cxl/main.c b/drivers/misc/cxl/main.c
> index 90933eb..a9051512 100644
> --- a/drivers/misc/cxl/main.c
> +++ b/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;
>
> diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
> index 3103e33..16d3b1a 100644
> --- a/drivers/misc/cxl/native.c
> +++ b/drivers/misc/cxl/native.c
> @@ -42,7 +42,7 @@ static int afu_control(struct cxl_afu *afu, u64 command,
>               goto out;
>           }
>
> -        if (!cxl_adapter_link_ok(afu->adapter)) {
> +        if (!cxl_ops->link_ok(afu->adapter)) {
>               afu->enabled = enabled;
>               rc = -EIO;
>               goto out;
> @@ -80,7 +80,7 @@ int cxl_afu_disable(struct cxl_afu *afu)
>   }
>
>   /* This will disable as well as reset */
> -int __cxl_afu_reset(struct cxl_afu *afu)
> +static int __cxl_afu_reset(struct cxl_afu *afu)
>   {
>       pr_devel("AFU reset request\n");
>
> @@ -90,9 +90,9 @@ int __cxl_afu_reset(struct cxl_afu *afu)
>                  false);
>   }
>
> -int cxl_afu_check_and_enable(struct cxl_afu *afu)
> +static int cxl_afu_check_and_enable(struct cxl_afu *afu)
>   {
> -    if (!cxl_adapter_link_ok(afu->adapter)) {
> +    if (!cxl_ops->link_ok(afu->adapter)) {
>           WARN(1, "Refusing to enable afu while link down!\n");
>           return -EIO;
>       }
> @@ -114,7 +114,7 @@ int cxl_psl_purge(struct cxl_afu *afu)
>
>       pr_devel("PSL purge request\n");
>
> -    if (!cxl_adapter_link_ok(afu->adapter)) {
> +    if (!cxl_ops->link_ok(afu->adapter)) {
>           dev_warn(&afu->dev, "PSL Purge called with link down,
> ignoring\n");
>           rc = -EIO;
>           goto out;
> @@ -136,7 +136,7 @@ int cxl_psl_purge(struct cxl_afu *afu)
>               rc = -EBUSY;
>               goto out;
>           }
> -        if (!cxl_adapter_link_ok(afu->adapter)) {
> +        if (!cxl_ops->link_ok(afu->adapter)) {
>               rc = -EIO;
>               goto out;
>           }
> @@ -247,7 +247,7 @@ int cxl_tlb_slb_invalidate(struct cxl *adapter)
>               dev_warn(&adapter->dev, "WARNING: CXL adapter wide TLBIA
> timed out!\n");
>               return -EBUSY;
>           }
> -        if (!cxl_adapter_link_ok(adapter))
> +        if (!cxl_ops->link_ok(adapter))
>               return -EIO;
>           cpu_relax();
>       }
> @@ -258,7 +258,7 @@ int cxl_tlb_slb_invalidate(struct cxl *adapter)
>               dev_warn(&adapter->dev, "WARNING: CXL adapter wide SLBIA
> timed out!\n");
>               return -EBUSY;
>           }
> -        if (!cxl_adapter_link_ok(adapter))
> +        if (!cxl_ops->link_ok(adapter))
>               return -EIO;
>           cpu_relax();
>       }
> @@ -299,7 +299,7 @@ static void slb_invalid(struct cxl_context *ctx)
>       cxl_p1_write(adapter, CXL_PSL_SLBIA, CXL_TLB_SLB_IQ_LPIDPID);
>
>       while (1) {
> -        if (!cxl_adapter_link_ok(adapter))
> +        if (!cxl_ops->link_ok(adapter))
>               break;
>           slbia = cxl_p1_read(adapter, CXL_PSL_SLBIA);
>           if (!(slbia & CXL_TLB_SLB_P))
> @@ -330,7 +330,7 @@ static int do_process_element_cmd(struct cxl_context
> *ctx,
>               rc = -EBUSY;
>               goto out;
>           }
> -        if (!cxl_adapter_link_ok(ctx->afu->adapter)) {
> +        if (!cxl_ops->link_ok(ctx->afu->adapter)) {
>               dev_warn(&ctx->afu->dev, "WARNING: Device link down,
> aborting Process Element Command!\n");
>               rc = -EIO;
>               goto out;
> @@ -386,7 +386,7 @@ static int terminate_process_element(struct
> cxl_context *ctx)
>        * should always succeed: it's not running if the hw has gone
>        * away and is being reset.
>        */
> -    if (cxl_adapter_link_ok(ctx->afu->adapter))
> +    if (cxl_ops->link_ok(ctx->afu->adapter))
>           rc = do_process_element_cmd(ctx, CXL_SPA_SW_CMD_TERMINATE,
>                           CXL_PE_SOFTWARE_STATE_V |
> CXL_PE_SOFTWARE_STATE_T);
>       ctx->elem->software_state = 0;    /* Remove Valid bit */
> @@ -405,7 +405,7 @@ static int remove_process_element(struct cxl_context
> *ctx)
>       /* We could be asked to remove when the hw is down. Again, if
>        * the hw is down, the PE is gone, so we succeed.
>        */
> -    if (cxl_adapter_link_ok(ctx->afu->adapter))
> +    if (cxl_ops->link_ok(ctx->afu->adapter))
>           rc = do_process_element_cmd(ctx, CXL_SPA_SW_CMD_REMOVE, 0);
>
>       if (!rc)
> @@ -531,7 +531,7 @@ static int attach_afu_directed(struct cxl_context
> *ctx, u64 wed, u64 amr)
>       ctx->elem->common.wed = cpu_to_be64(wed);
>
>       /* first guy needs to enable */
> -    if ((result = cxl_afu_check_and_enable(ctx->afu)))
> +    if ((result = cxl_ops->afu_check_and_enable(ctx->afu)))
>           return result;
>
>       return add_process_element(ctx);
> @@ -547,7 +547,7 @@ static int deactivate_afu_directed(struct cxl_afu *afu)
>       cxl_sysfs_afu_m_remove(afu);
>       cxl_chardev_afu_remove(afu);
>
> -    __cxl_afu_reset(afu);
> +    cxl_ops->afu_reset(afu);
>       cxl_afu_disable(afu);
>       cxl_psl_purge(afu);
>
> @@ -611,7 +611,7 @@ static int attach_dedicated(struct cxl_context *ctx,
> u64 wed, u64 amr)
>       /* master only context for dedicated */
>       cxl_assign_psn_space(ctx);
>
> -    if ((rc = __cxl_afu_reset(afu)))
> +    if ((rc = cxl_ops->afu_reset(afu)))
>           return rc;
>
>       cxl_p2n_write(afu, CXL_PSL_WED_An, wed);
> @@ -631,7 +631,7 @@ static int deactivate_dedicated_process(struct
> cxl_afu *afu)
>       return 0;
>   }
>
> -int _cxl_afu_deactivate_mode(struct cxl_afu *afu, int mode)
> +static int cxl_afu_deactivate_mode(struct cxl_afu *afu, int mode)
>   {
>       if (mode == CXL_MODE_DIRECTED)
>           return deactivate_afu_directed(afu);
> @@ -640,19 +640,14 @@ int _cxl_afu_deactivate_mode(struct cxl_afu *afu,
> int mode)
>       return 0;
>   }
>
> -int cxl_afu_deactivate_mode(struct cxl_afu *afu)
> -{
> -    return _cxl_afu_deactivate_mode(afu, afu->current_mode);
> -}
> -
> -int cxl_afu_activate_mode(struct cxl_afu *afu, int mode)
> +static int cxl_afu_activate_mode(struct cxl_afu *afu, int mode)
>   {
>       if (!mode)
>           return 0;
>       if (!(mode & afu->modes_supported))
>           return -EINVAL;
>
> -    if (!cxl_adapter_link_ok(afu->adapter)) {
> +    if (!cxl_ops->link_ok(afu->adapter)) {
>           WARN(1, "Device link is down, refusing to activate!\n");
>           return -EIO;
>       }
> @@ -665,9 +660,9 @@ int cxl_afu_activate_mode(struct cxl_afu *afu, int
> mode)
>       return -EINVAL;
>   }
>
> -int cxl_attach_process(struct cxl_context *ctx, bool kernel, u64 wed,
> u64 amr)
> +static int cxl_attach_process(struct cxl_context *ctx, bool kernel, u64
> wed, u64 amr)
>   {
> -    if (!cxl_adapter_link_ok(ctx->afu->adapter)) {
> +    if (!cxl_ops->link_ok(ctx->afu->adapter)) {
>           WARN(1, "Device link is down, refusing to attach process!\n");
>           return -EIO;
>       }
> @@ -684,7 +679,7 @@ int cxl_attach_process(struct cxl_context *ctx, bool
> kernel, u64 wed, u64 amr)
>
>   static inline int detach_process_native_dedicated(struct cxl_context
> *ctx)
>   {
> -    __cxl_afu_reset(ctx->afu);
> +    cxl_ops->afu_reset(ctx->afu);
>       cxl_afu_disable(ctx->afu);
>       cxl_psl_purge(ctx->afu);
>       return 0;
> @@ -702,7 +697,7 @@ static inline int
> detach_process_native_afu_directed(struct cxl_context *ctx)
>       return 0;
>   }
>
> -int cxl_detach_process(struct cxl_context *ctx)
> +static int cxl_detach_process(struct cxl_context *ctx)
>   {
>       trace_cxl_detach(ctx);
>
> @@ -719,7 +714,7 @@ static int cxl_get_irq(struct cxl_afu *afu, struct
> cxl_irq_info *info)
>       /* If the adapter has gone away, we can't get any meaningful
>        * information.
>        */
> -    if (!cxl_adapter_link_ok(afu->adapter))
> +    if (!cxl_ops->link_ok(afu->adapter))
>           return -EIO;
>
>       info->dsisr = cxl_p2n_read(afu, CXL_PSL_DSISR_An);
> @@ -734,7 +729,7 @@ static int cxl_get_irq(struct cxl_afu *afu, struct
> cxl_irq_info *info)
>       return 0;
>   }
>
> -irqreturn_t handle_psl_slice_error(struct cxl_context *ctx, u64 dsisr,
> u64 errstat)
> +static irqreturn_t handle_psl_slice_error(struct cxl_context *ctx, u64
> dsisr, u64 errstat)
>   {
>       u64 fir1, fir2, fir_slice, serr, afu_debug;
>
> @@ -754,7 +749,7 @@ irqreturn_t handle_psl_slice_error(struct
> cxl_context *ctx, u64 dsisr, u64 errst
>       dev_crit(&ctx->afu->dev, "STOPPING CXL TRACE\n");
>       cxl_stop_trace(ctx->afu->adapter);
>
> -    return cxl_ack_irq(ctx, 0, errstat);
> +    return cxl_ops->ack_irq(ctx, 0, errstat);
>   }
>
>   static irqreturn_t fail_psl_irq(struct cxl_afu *afu, struct
> cxl_irq_info *irq_info)
> @@ -868,7 +863,7 @@ void cxl_release_psl_err_irq(struct cxl *adapter)
>
>       cxl_p1_write(adapter, CXL_PSL_ErrIVTE, 0x0000000000000000);
>       cxl_unmap_irq(adapter->err_virq, adapter);
> -    cxl_release_one_irq(adapter, adapter->err_hwirq);
> +    cxl_ops->release_one_irq(adapter, adapter->err_hwirq);
>       kfree(adapter->irq_name);
>   }
>
> @@ -904,7 +899,7 @@ void cxl_release_serr_irq(struct cxl_afu *afu)
>
>       cxl_p1n_write(afu, CXL_PSL_SERR_An, 0x0000000000000000);
>       cxl_unmap_irq(afu->serr_virq, afu);
> -    cxl_release_one_irq(afu->adapter, afu->serr_hwirq);
> +    cxl_ops->release_one_irq(afu->adapter, afu->serr_hwirq);
>       kfree(afu->err_irq_name);
>   }
>
> @@ -932,7 +927,7 @@ void cxl_release_psl_irq(struct cxl_afu *afu)
>           return;
>
>       cxl_unmap_irq(afu->psl_virq, afu);
> -    cxl_release_one_irq(afu->adapter, afu->psl_hwirq);
> +    cxl_ops->release_one_irq(afu->adapter, afu->psl_hwirq);
>       kfree(afu->psl_irq_name);
>   }
>
> @@ -950,7 +945,7 @@ static void recover_psl_err(struct cxl_afu *afu, u64
> errstat)
>       cxl_p2n_write(afu, CXL_PSL_ErrStat_An, errstat);
>   }
>
> -int cxl_ack_irq(struct cxl_context *ctx, u64 tfc, u64 psl_reset_mask)
> +static int cxl_ack_irq(struct cxl_context *ctx, u64 tfc, u64
> psl_reset_mask)
>   {
>       trace_cxl_psl_irq_ack(ctx, tfc);
>       if (tfc)
> @@ -966,38 +961,74 @@ int cxl_check_error(struct cxl_afu *afu)
>       return (cxl_p1n_read(afu, CXL_PSL_SCNTL_An) == ~0ULL);
>   }
>
> -u64 cxl_afu_cr_read64(struct cxl_afu *afu, int cr, u64 off)
> +static int cxl_afu_cr_read64(struct cxl_afu *afu, int cr, u64 off, u64
> *out)
>   {
> -    if (likely(cxl_adapter_link_ok(afu->adapter)))
> -        return in_le64((afu)->afu_desc_mmio + (afu)->crs_offset +
> -                   ((cr) * (afu)->crs_len) + (off));
> -    else
> -        return ~0ULL;
> +    if (unlikely(!cxl_ops->link_ok(afu->adapter)))
> +        return -EIO;
> +    if (unlikely(off >= afu->crs_len))
> +        return -ERANGE;
> +    *out = in_le64(afu->afu_desc_mmio + afu->crs_offset +
> +        (cr * afu->crs_len) + off);
> +    return 0;
>   }
>
> -u32 cxl_afu_cr_read32(struct cxl_afu *afu, int cr, u64 off)
> +static int cxl_afu_cr_read32(struct cxl_afu *afu, int cr, u64 off, u32
> *out)
>   {
> -    if (likely(cxl_adapter_link_ok(afu->adapter)))
> -        return in_le32((afu)->afu_desc_mmio + (afu)->crs_offset +
> -                   ((cr) * (afu)->crs_len) + (off));
> -    else
> -        return 0xffffffff;
> +    if (unlikely(!cxl_ops->link_ok(afu->adapter)))
> +        return -EIO;
> +    if (unlikely(off >= afu->crs_len))
> +        return -ERANGE;
> +    *out = in_le32(afu->afu_desc_mmio + afu->crs_offset +
> +        (cr * afu->crs_len) + off);
> +    return 0;
>   }
>
> -u16 cxl_afu_cr_read16(struct cxl_afu *afu, int cr, u64 off)
> +static int cxl_afu_cr_read16(struct cxl_afu *afu, int cr, u64 off, u16
> *out)
>   {
>       u64 aligned_off = off & ~0x3L;
>       u32 val;
> +    int rc;
>
> -    val = cxl_afu_cr_read32(afu, cr, aligned_off);
> -    return (val >> ((off & 0x2) * 8)) & 0xffff;
> +    rc = cxl_afu_cr_read32(afu, cr, aligned_off, &val);
> +    if (!rc)
> +        *out = (val >> ((off & 0x3) * 8)) & 0xffff;
> +    return rc;
>   }
>
> -u8 cxl_afu_cr_read8(struct cxl_afu *afu, int cr, u64 off)
> +static int cxl_afu_cr_read8(struct cxl_afu *afu, int cr, u64 off, u8 *out)
>   {
>       u64 aligned_off = off & ~0x3L;
>       u32 val;
> +    int rc;
>
> -    val = cxl_afu_cr_read32(afu, cr, aligned_off);
> -    return (val >> ((off & 0x3) * 8)) & 0xff;
> +    rc = cxl_afu_cr_read32(afu, cr, aligned_off, &val);
> +    if (!rc)
> +        *out = (val >> ((off & 0x3) * 8)) & 0xff;
> +    return rc;
>   }
> +
> +const struct cxl_backend_ops cxl_native_ops = {
> +    .module = THIS_MODULE,
> +    .adapter_reset = cxl_reset,
> +    .alloc_one_irq = cxl_alloc_one_irq,
> +    .release_one_irq = cxl_release_one_irq,
> +    .alloc_irq_ranges = cxl_alloc_irq_ranges,
> +    .release_irq_ranges = cxl_release_irq_ranges,
> +    .setup_irq = cxl_setup_irq,
> +    .handle_psl_slice_error = handle_psl_slice_error,
> +    .psl_interrupt = NULL,
> +    .ack_irq = cxl_ack_irq,
> +    .attach_process = cxl_attach_process,
> +    .detach_process = cxl_detach_process,
> +    .link_ok = cxl_adapter_link_ok,
> +    .release_afu = cxl_release_afu,
> +    .afu_read_err_buffer = cxl_afu_read_err_buffer,
> +    .afu_check_and_enable = cxl_afu_check_and_enable,
> +    .afu_activate_mode = cxl_afu_activate_mode,
> +    .afu_deactivate_mode = cxl_afu_deactivate_mode,
> +    .afu_reset = __cxl_afu_reset,
> +    .afu_cr_read8 = cxl_afu_cr_read8,
> +    .afu_cr_read16 = cxl_afu_cr_read16,
> +    .afu_cr_read32 = cxl_afu_cr_read32,
> +    .afu_cr_read64 = cxl_afu_cr_read64,
> +};
> diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
> index c6279e5..6e2c274 100644
> --- a/drivers/misc/cxl/pci.c
> +++ b/drivers/misc/cxl/pci.c
> @@ -646,7 +646,8 @@ static int cxl_read_afu_descriptor(struct cxl_afu *afu)
>
>   static int cxl_afu_descriptor_looks_ok(struct cxl_afu *afu)
>   {
> -    int i;
> +    int i, rc;
> +    u32 val;
>
>       if (afu->psa && afu->adapter->ps_size <
>               (afu->pp_offset + afu->pp_size*afu->max_procs_virtualised)) {
> @@ -658,7 +659,8 @@ static int cxl_afu_descriptor_looks_ok(struct
> cxl_afu *afu)
>           dev_warn(&afu->dev, "AFU uses < PAGE_SIZE per-process PSA!");
>
>       for (i = 0; i < afu->crs_num; i++) {
> -        if ((cxl_afu_cr_read32(afu, i, 0) == 0)) {
> +        rc = cxl_ops->afu_cr_read32(afu, i, 0, &val);
> +        if (rc || val == 0) {
>               dev_err(&afu->dev, "ABORTING: AFU configuration record %i
> is invalid\n", i);
>               return -EINVAL;
>           }
> @@ -679,7 +681,7 @@ static int sanitise_afu_regs(struct cxl_afu *afu)
>       reg = cxl_p2n_read(afu, CXL_AFU_Cntl_An);
>       if ((reg & CXL_AFU_Cntl_An_ES_MASK) != CXL_AFU_Cntl_An_ES_Disabled) {
>           dev_warn(&afu->dev, "WARNING: AFU was not disabled:
> %#016llx\n", reg);
> -        if (__cxl_afu_reset(afu))
> +        if (cxl_ops->afu_reset(afu))
>               return -EIO;
>           if (cxl_afu_disable(afu))
>               return -EIO;
> @@ -775,7 +777,7 @@ static int cxl_configure_afu(struct cxl_afu *afu,
> struct cxl *adapter, struct pc
>           goto err1;
>
>       /* We need to reset the AFU before we can read the AFU descriptor */
> -    if ((rc = __cxl_afu_reset(afu)))
> +    if ((rc = cxl_ops->afu_reset(afu)))
>           goto err1;
>
>       if (cxl_verbose)
> @@ -876,7 +878,7 @@ static void cxl_remove_afu(struct cxl_afu *afu)
>       spin_unlock(&afu->adapter->afu_list_lock);
>
>       cxl_context_detach_all(afu);
> -    cxl_afu_deactivate_mode(afu);
> +    cxl_ops->afu_deactivate_mode(afu, afu->current_mode);
>
>       cxl_deconfigure_afu(afu);
>       device_unregister(&afu->dev);
> @@ -1398,7 +1400,7 @@ static pci_ers_result_t
> cxl_pci_error_detected(struct pci_dev *pdev,
>               return result;
>
>           cxl_context_detach_all(afu);
> -        cxl_afu_deactivate_mode(afu);
> +        cxl_ops->afu_deactivate_mode(afu, afu->current_mode);
>           cxl_deconfigure_afu(afu);
>       }
>       cxl_deconfigure_adapter(adapter);
> @@ -1445,7 +1447,7 @@ static pci_ers_result_t cxl_pci_slot_reset(struct
> pci_dev *pdev)
>
>               afu_dev->dev.archdata.cxl_ctx = ctx;
>
> -            if (cxl_afu_check_and_enable(afu))
> +            if (cxl_ops->afu_check_and_enable(afu))
>                   goto err;
>
>               afu_dev->error_state = pci_channel_io_normal;
> diff --git a/drivers/misc/cxl/sysfs.c b/drivers/misc/cxl/sysfs.c
> index 02006f71..300eafe 100644
> --- a/drivers/misc/cxl/sysfs.c
> +++ b/drivers/misc/cxl/sysfs.c
> @@ -69,7 +69,7 @@ static ssize_t reset_adapter_store(struct device *device,
>       if ((rc != 1) || (val != 1))
>           return -EINVAL;
>
> -    if ((rc = cxl_reset(adapter)))
> +    if ((rc = cxl_ops->adapter_reset(adapter)))
>           return rc;
>       return count;
>   }
> @@ -211,7 +211,7 @@ static ssize_t reset_store_afu(struct device *device,
>           goto err;
>       }
>
> -    if ((rc = __cxl_afu_reset(afu)))
> +    if ((rc = cxl_ops->afu_reset(afu)))
>           goto err;
>
>       rc = count;
> @@ -348,7 +348,7 @@ static ssize_t mode_store(struct device *device,
> struct device_attribute *attr,
>       }
>
>       /*
> -     * cxl_afu_deactivate_mode needs to be done outside the lock, prevent
> +     * afu_deactivate_mode needs to be done outside the lock, prevent
>        * other contexts coming in before we are ready:
>        */
>       old_mode = afu->current_mode;
> @@ -357,9 +357,9 @@ static ssize_t mode_store(struct device *device,
> struct device_attribute *attr,
>
>       mutex_unlock(&afu->contexts_lock);
>
> -    if ((rc = _cxl_afu_deactivate_mode(afu, old_mode)))
> +    if ((rc = cxl_ops->afu_deactivate_mode(afu, old_mode)))
>           return rc;
> -    if ((rc = cxl_afu_activate_mode(afu, mode)))
> +    if ((rc = cxl_ops->afu_activate_mode(afu, mode)))
>           return rc;
>
>       return count;
> @@ -389,7 +389,7 @@ static ssize_t afu_eb_read(struct file *filp, struct
> kobject *kobj,
>       struct cxl_afu *afu = to_cxl_afu(container_of(kobj,
>                                 struct device, kobj));
>
> -    return cxl_afu_read_err_buffer(afu, buf, off, count);
> +    return cxl_ops->afu_read_err_buffer(afu, buf, off, count);
>   }
>
>   static struct device_attribute afu_attrs[] = {
> @@ -469,10 +469,12 @@ static ssize_t afu_read_config(struct file *filp,
> struct kobject *kobj,
>       struct afu_config_record *cr = to_cr(kobj);
>       struct cxl_afu *afu = to_cxl_afu(container_of(kobj->parent, struct
> device, kobj));
>
> -    u64 i, j, val;
> +    u64 i, j, val, rc;
>
>       for (i = 0; i < count;) {
> -        val = cxl_afu_cr_read64(afu, cr->cr, off & ~0x7);
> +        rc = cxl_ops->afu_cr_read64(afu, cr->cr, off & ~0x7, &val);
> +        if (rc)
> +            val = ~0ULL;
>           for (j = off & 0x7; j < 8 && i < count; i++, j++, off++)
>               buf[i] = (val >> (j * 8)) & 0xff;
>       }
> @@ -517,9 +519,17 @@ static struct afu_config_record
> *cxl_sysfs_afu_new_cr(struct cxl_afu *afu, int c
>           return ERR_PTR(-ENOMEM);
>
>       cr->cr = cr_idx;
> -    cr->device = cxl_afu_cr_read16(afu, cr_idx, PCI_DEVICE_ID);
> -    cr->vendor = cxl_afu_cr_read16(afu, cr_idx, PCI_VENDOR_ID);
> -    cr->class = cxl_afu_cr_read32(afu, cr_idx, PCI_CLASS_REVISION) >> 8;
> +
> +    rc = cxl_ops->afu_cr_read16(afu, cr_idx, PCI_DEVICE_ID, &cr->device);
> +    if (rc)
> +        goto err;
> +    rc = cxl_ops->afu_cr_read16(afu, cr_idx, PCI_VENDOR_ID, &cr->vendor);
> +    if (rc)
> +        goto err;
> +    rc = cxl_ops->afu_cr_read32(afu, cr_idx, PCI_CLASS_REVISION,
> &cr->class);
> +    if (rc)
> +        goto err;
> +    cr->class >>= 8;
>
>       /*
>        * Export raw AFU PCIe like config record. For now this is read
> only by
> diff --git a/drivers/misc/cxl/vphb.c b/drivers/misc/cxl/vphb.c
> index cbd4331..e8a8eed 100644
> --- a/drivers/misc/cxl/vphb.c
> +++ b/drivers/misc/cxl/vphb.c
> @@ -49,7 +49,7 @@ static bool cxl_pci_enable_device_hook(struct pci_dev
> *dev)
>       phb = pci_bus_to_host(dev->bus);
>       afu = (struct cxl_afu *)phb->private_data;
>
> -    if (!cxl_adapter_link_ok(afu->adapter)) {
> +    if (!cxl_ops->link_ok(afu->adapter)) {
>           dev_warn(&dev->dev, "%s: Device link is down, refusing to
> enable AFU\n", __func__);
>           return false;
>       }
> @@ -66,7 +66,7 @@ static bool cxl_pci_enable_device_hook(struct pci_dev
> *dev)
>           return false;
>       dev->dev.archdata.cxl_ctx = ctx;
>
> -    return (cxl_afu_check_and_enable(afu) == 0);
> +    return (cxl_ops->afu_check_and_enable(afu) == 0);
>   }
>
>   static void cxl_pci_disable_device(struct pci_dev *dev)
> @@ -161,7 +161,7 @@ static inline bool cxl_config_link_ok(struct pci_bus
> *bus)
>       if (phb == NULL)
>           return false;
>       afu = (struct cxl_afu *)phb->private_data;
> -    return cxl_adapter_link_ok(afu->adapter);
> +    return cxl_ops->link_ok(afu->adapter);
>   }
>
>   static int cxl_pcie_read_config(struct pci_bus *bus, unsigned int devfn,