powerpc/powernv/vas: Define helpers to alloc/free windows

Define helpers to allocate/free VAS window objects. These will be used
in follow-on patches when opening/closing windows.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index 68dfe538e0f66af1d8d01ad4a09b87efeff2cc62..bfc9dba24b65b3e99c076006be503336a8c21d1d 100644 (file)
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -485,6 +485,79 @@ int init_winctx_regs(struct vas_window *window, struct vas_winctx *winctx)
        return 0;
 }
 
+static DEFINE_SPINLOCK(vas_ida_lock);
+
+static void vas_release_window_id(struct ida *ida, int winid)
+{
+       spin_lock(&vas_ida_lock);
+       ida_remove(ida, winid);
+       spin_unlock(&vas_ida_lock);
+}
+
+static int vas_assign_window_id(struct ida *ida)
+{
+       int rc, winid;
+
+       do {
+               rc = ida_pre_get(ida, GFP_KERNEL);
+               if (!rc)
+                       return -EAGAIN;
+
+               spin_lock(&vas_ida_lock);
+               rc = ida_get_new(ida, &winid);
+               spin_unlock(&vas_ida_lock);
+       } while (rc == -EAGAIN);
+
+       if (rc)
+               return rc;
+
+       if (winid > VAS_WINDOWS_PER_CHIP) {
+               pr_err("Too many (%d) open windows\n", winid);
+               vas_release_window_id(ida, winid);
+               return -EAGAIN;
+       }
+
+       return winid;
+}
+
+void vas_window_free(struct vas_window *window)
+{
+       int winid = window->winid;
+       struct vas_instance *vinst = window->vinst;
+
+       unmap_winctx_mmio_bars(window);
+       kfree(window);
+
+       vas_release_window_id(&vinst->ida, winid);
+}
+
+struct vas_window *vas_window_alloc(struct vas_instance *vinst)
+{
+       int winid;
+       struct vas_window *window;
+
+       winid = vas_assign_window_id(&vinst->ida);
+       if (winid < 0)
+               return ERR_PTR(winid);
+
+       window = kzalloc(sizeof(*window), GFP_KERNEL);
+       if (!window)
+               goto out_free;
+
+       window->vinst = vinst;
+       window->winid = winid;
+
+       if (map_winctx_mmio_bars(window))
+               goto out_free;
+
+       return window;
+
+out_free:
+       kfree(window);
+       vas_release_window_id(&vinst->ida, winid);
+       return ERR_PTR(-ENOMEM);
+}
+
 /* stub for now */
 int vas_win_close(struct vas_window *window)
 {