[PATCH v2 4/6] block/nvme: Drop NVMeRegs structure, directly use NvmeBar

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

NVMeRegs only contains NvmeBar. Simplify the code by using NvmeBar
directly.

This triggers a checkpatch.pl error:

  ERROR: Use of volatile is usually wrong, please add a comment
  #30: FILE: block/nvme.c:691:
  +    volatile NvmeBar *regs;

This is a false positive as in our case we are using I/O registers,
so the 'volatile' use is justified.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 block/nvme.c | 23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/block/nvme.c b/block/nvme.c
index e517c7539ff..bd82990b66c 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -81,11 +81,6 @@ typedef struct {
     QEMUBH      *completion_bh;
 } NVMeQueuePair;
 
-/* Memory mapped registers */
-typedef volatile struct {
-    NvmeBar ctrl;
-} NVMeRegs;
-
 #define INDEX_ADMIN     0
 #define INDEX_IO(n)     (1 + n)
 
@@ -694,7 +689,7 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
     uint64_t timeout_ms;
     uint64_t deadline, now;
     Error *local_err = NULL;
-    NVMeRegs *regs;
+    volatile NvmeBar *regs = NULL;
 
     qemu_co_mutex_init(&s->dma_map_lock);
     qemu_co_queue_init(&s->dma_flush_queue);
@@ -722,7 +717,7 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
     /* Perform initialize sequence as described in NVMe spec "7.6.1
      * Initialization". */
 
-    cap = le64_to_cpu(regs->ctrl.cap);
+    cap = le64_to_cpu(regs->cap);
     if (!(cap & (1ULL << 37))) {
         error_setg(errp, "Device doesn't support NVMe command set");
         ret = -EINVAL;
@@ -735,10 +730,10 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
     timeout_ms = MIN(500 * ((cap >> 24) & 0xFF), 30000);
 
     /* Reset device to get a clean state. */
-    regs->ctrl.cc = cpu_to_le32(le32_to_cpu(regs->ctrl.cc) & 0xFE);
+    regs->cc = cpu_to_le32(le32_to_cpu(regs->cc) & 0xFE);
     /* Wait for CSTS.RDY = 0. */
     deadline = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + timeout_ms * SCALE_MS;
-    while (le32_to_cpu(regs->ctrl.csts) & 0x1) {
+    while (le32_to_cpu(regs->csts) & 0x1) {
         if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) > deadline) {
             error_setg(errp, "Timeout while waiting for device to reset (%"
                              PRId64 " ms)",
@@ -766,18 +761,18 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
     }
     s->nr_queues = 1;
     QEMU_BUILD_BUG_ON(NVME_QUEUE_SIZE & 0xF000);
-    regs->ctrl.aqa = cpu_to_le32((NVME_QUEUE_SIZE << 16) | NVME_QUEUE_SIZE);
-    regs->ctrl.asq = cpu_to_le64(s->queues[INDEX_ADMIN]->sq.iova);
-    regs->ctrl.acq = cpu_to_le64(s->queues[INDEX_ADMIN]->cq.iova);
+    regs->aqa = cpu_to_le32((NVME_QUEUE_SIZE << 16) | NVME_QUEUE_SIZE);
+    regs->asq = cpu_to_le64(s->queues[INDEX_ADMIN]->sq.iova);
+    regs->acq = cpu_to_le64(s->queues[INDEX_ADMIN]->cq.iova);
 
     /* After setting up all control registers we can enable device now. */
-    regs->ctrl.cc = cpu_to_le32((ctz32(NVME_CQ_ENTRY_BYTES) << 20) |
+    regs->cc = cpu_to_le32((ctz32(NVME_CQ_ENTRY_BYTES) << 20) |
                               (ctz32(NVME_SQ_ENTRY_BYTES) << 16) |
                               0x1);
     /* Wait for CSTS.RDY = 1. */
     now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
     deadline = now + timeout_ms * 1000000;
-    while (!(le32_to_cpu(regs->ctrl.csts) & 0x1)) {
+    while (!(le32_to_cpu(regs->csts) & 0x1)) {
         if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) > deadline) {
             error_setg(errp, "Timeout while waiting for device to start (%"
                              PRId64 " ms)",
-- 
2.26.2