[PATCH v4 17/23] xen/arm: introduce a union in vpl011

[Stefano Stabellini <sstabellini@kernel.org>]

Introduce a union in struct vpl011 to contain the console ring members.
A later patch will add another member of the union for the case where
the backend is in Xen.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
---
Changes in v4:
- name union "backend"

Changes in v3:
- rename ring field to dom

Changes in v2:
- new patch
---
 xen/arch/arm/vpl011.c        | 22 ++++++++++++----------
 xen/include/asm-arm/vpl011.h |  8 ++++++--
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/xen/arch/arm/vpl011.c b/xen/arch/arm/vpl011.c
index a281eab..ebc045e 100644
--- a/xen/arch/arm/vpl011.c
+++ b/xen/arch/arm/vpl011.c
@@ -82,7 +82,7 @@ static uint8_t vpl011_read_data(struct domain *d)
     unsigned long flags;
     uint8_t data = 0;
     struct vpl011 *vpl011 = &d->arch.vpl011;
-    struct xencons_interface *intf = vpl011->ring_buf;
+    struct xencons_interface *intf = vpl011->backend.dom.ring_buf;
     XENCONS_RING_IDX in_cons, in_prod;
 
     VPL011_LOCK(d, flags);
@@ -145,7 +145,7 @@ static uint8_t vpl011_read_data(struct domain *d)
 static void vpl011_update_tx_fifo_status(struct vpl011 *vpl011,
                                          unsigned int fifo_level)
 {
-    struct xencons_interface *intf = vpl011->ring_buf;
+    struct xencons_interface *intf = vpl011->backend.dom.ring_buf;
     unsigned int fifo_threshold = sizeof(intf->out) - SBSA_UART_FIFO_LEVEL;
 
     BUILD_BUG_ON(sizeof(intf->out) < SBSA_UART_FIFO_SIZE);
@@ -164,7 +164,7 @@ static void vpl011_write_data(struct domain *d, uint8_t data)
 {
     unsigned long flags;
     struct vpl011 *vpl011 = &d->arch.vpl011;
-    struct xencons_interface *intf = vpl011->ring_buf;
+    struct xencons_interface *intf = vpl011->backend.dom.ring_buf;
     XENCONS_RING_IDX out_cons, out_prod;
 
     VPL011_LOCK(d, flags);
@@ -382,7 +382,7 @@ static void vpl011_data_avail(struct domain *d)
 {
     unsigned long flags;
     struct vpl011 *vpl011 = &d->arch.vpl011;
-    struct xencons_interface *intf = vpl011->ring_buf;
+    struct xencons_interface *intf = vpl011->backend.dom.ring_buf;
     XENCONS_RING_IDX in_cons, in_prod, out_cons, out_prod;
     XENCONS_RING_IDX in_fifo_level, out_fifo_level;
 
@@ -459,14 +459,14 @@ int domain_vpl011_init(struct domain *d, struct vpl011_init_info *info)
     int rc;
     struct vpl011 *vpl011 = &d->arch.vpl011;
 
-    if ( vpl011->ring_buf )
+    if ( vpl011->backend.dom.ring_buf )
         return -EINVAL;
 
     /* Map the guest PFN to Xen address space. */
     rc =  prepare_ring_for_helper(d,
                                   gfn_x(info->gfn),
-                                  &vpl011->ring_page,
-                                  &vpl011->ring_buf);
+                                  &vpl011->backend.dom.ring_page,
+                                  &vpl011->backend.dom.ring_buf);
     if ( rc < 0 )
         goto out;
 
@@ -495,7 +495,8 @@ out2:
     vgic_free_virq(d, GUEST_VPL011_SPI);
 
 out1:
-    destroy_ring_for_helper(&vpl011->ring_buf, vpl011->ring_page);
+    destroy_ring_for_helper(&vpl011->backend.dom.ring_buf,
+			                vpl011->backend.dom.ring_page);
 
 out:
     return rc;
@@ -505,11 +506,12 @@ void domain_vpl011_deinit(struct domain *d)
 {
     struct vpl011 *vpl011 = &d->arch.vpl011;
 
-    if ( !vpl011->ring_buf )
+    if ( !vpl011->backend.dom.ring_buf )
         return;
 
     free_xen_event_channel(d, vpl011->evtchn);
-    destroy_ring_for_helper(&vpl011->ring_buf, vpl011->ring_page);
+    destroy_ring_for_helper(&vpl011->backend.dom.ring_buf,
+			                vpl011->backend.dom.ring_page);
 }
 
 /*
diff --git a/xen/include/asm-arm/vpl011.h b/xen/include/asm-arm/vpl011.h
index db95ff8..42d7a24 100644
--- a/xen/include/asm-arm/vpl011.h
+++ b/xen/include/asm-arm/vpl011.h
@@ -31,8 +31,12 @@
 #define SBSA_UART_FIFO_SIZE 32
 
 struct vpl011 {
-    void *ring_buf;
-    struct page_info *ring_page;
+    union {
+        struct {
+            void *ring_buf;
+            struct page_info *ring_page;
+        } dom;
+    } backend;
     uint32_t    uartfr;         /* Flag register */
     uint32_t    uartcr;         /* Control register */
     uint32_t    uartimsc;       /* Interrupt mask register*/
-- 
1.9.1


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