[Qemu-devel] [PATCH v8 3/8] register: Add Memory API glue

[Alistair Francis]

Add memory io handlers that glue the register API to the memory API.
Just translation functions at this stage. Although it does allow for
devices to be created without all-in-one mmio r/w handlers.

This patch also adds the RegisterInfoArray struct, which allows all of
the individual RegisterInfo structs to be grouped into a single memory
region.

Signed-off-by: Peter Crosthwaite <address@hidden>
Signed-off-by: Alistair Francis <address@hidden>
---
V8:
 - Mask reads based on size as well as writes
V7:
 - Remove endianess handling
 - Remove assert() and log missing registers
V6:
 - Add the memory region later
V5:
 - Convert to using only one memory region

 hw/core/register.c    | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/register.h | 43 +++++++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+)

diff --git a/hw/core/register.c b/hw/core/register.c
index e36169d..07f5d4f 100644
--- a/hw/core/register.c
+++ b/hw/core/register.c
@@ -157,3 +157,62 @@ void register_reset(RegisterInfo *reg)
 
     register_write_val(reg, reg->access->reset);
 }
+
+void register_write_memory(void *opaque, hwaddr addr,
+                           uint64_t value, unsigned size)
+{
+    RegisterInfoArray *reg_array = opaque;
+    RegisterInfo *reg = NULL;
+    uint64_t we;
+    int i;
+
+    for (i = 0; i < reg_array->num_elements; i++) {
+        if (reg_array->r[i]->access->addr == addr) {
+            reg = reg_array->r[i];
+            break;
+        }
+    }
+
+    if (!reg) {
+        qemu_log_mask(LOG_GUEST_ERROR, "Write to unimplemented register at " \
+                      "address: %#" PRIx64 "\n", addr);
+        return;
+    }
+
+    /* Generate appropriate write enable mask */
+    if (reg->data_size < size) {
+        we = MAKE_64BIT_MASK(0, reg->data_size * 8);
+    } else {
+        we = MAKE_64BIT_MASK(0, size * 8);
+    }
+
+    register_write(reg, value, we, reg_array->prefix,
+                   reg_array->debug);
+}
+
+uint64_t register_read_memory(void *opaque, hwaddr addr,
+                              unsigned size)
+{
+    RegisterInfoArray *reg_array = opaque;
+    RegisterInfo *reg = NULL;
+    uint64_t read_val;
+    int i;
+
+    for (i = 0; i < reg_array->num_elements; i++) {
+        if (reg_array->r[i]->access->addr == addr) {
+            reg = reg_array->r[i];
+            break;
+        }
+    }
+
+    if (!reg) {
+        qemu_log_mask(LOG_GUEST_ERROR, "Read to unimplemented register at " \
+                      "address: %#" PRIx64 "\n", addr);
+        return 0;
+    }
+
+    read_val = register_read(reg, size * 8, reg_array->prefix,
+                             reg_array->debug);
+
+    return extract64(read_val, 0, size * 8);
+}
diff --git a/include/hw/register.h b/include/hw/register.h
index 6a2bc75..00bbfe5 100644
--- a/include/hw/register.h
+++ b/include/hw/register.h
@@ -15,6 +15,7 @@
 
 typedef struct RegisterInfo RegisterInfo;
 typedef struct RegisterAccessInfo RegisterAccessInfo;
+typedef struct RegisterInfoArray RegisterInfoArray;
 
 /**
  * Access description for a register that is part of guest accessible device
@@ -51,6 +52,8 @@ struct RegisterAccessInfo {
     void (*post_write)(RegisterInfo *reg, uint64_t val);
 
     uint64_t (*post_read)(RegisterInfo *reg, uint64_t val);
+
+    hwaddr addr;
 };
 
 /**
@@ -79,6 +82,25 @@ struct RegisterInfo {
 };
 
 /**
+ * This structure is used to group all of the individual registers which are
+ * modeled using the RegisterInfo structure.
+ *
+ * @r is an aray containing of all the relevent RegisterInfo structures.
+ *
+ * @num_elements is the number of elements in the array r
+ *
+ * @mem: optional Memory region for the register
+ */
+
+struct RegisterInfoArray {
+    int num_elements;
+    RegisterInfo **r;
+
+    bool debug;
+    const char *prefix;
+};
+
+/**
  * write a value to a register, subject to its restrictions
  * @reg: register to write to
  * @val: value to write
@@ -109,4 +131,25 @@ uint64_t register_read(RegisterInfo *reg, uint64_t re, 
const char* prefix,
 
 void register_reset(RegisterInfo *reg);
 
+/**
+ * Memory API MMIO write handler that will write to a Register API register.
+ * @opaque: RegisterInfo to write to
+ * @addr: Address to write
+ * @value: Value to write
+ * @size: Number of bytes to write
+ */
+
+void register_write_memory(void *opaque, hwaddr addr, uint64_t value,
+                           unsigned size);
+
+/**
+ * Memory API MMIO read handler that will read from a Register API register.
+ * @opaque: RegisterInfo to read from
+ * @addr: Address to read
+ * @size: Number of bytes to read
+ * returns: Value read from register
+ */
+
+uint64_t register_read_memory(void *opaque, hwaddr addr, unsigned size);
+
 #endif
-- 
2.7.4