hw/arm: xlnx-zcu102: Add Xilinx BBRAM device

Connect the support for Xilinx ZynqMP Battery-Backed RAM (BBRAM)

The command argument:
  -drive if=pflash,index=2,...
Can be used to optionally connect the bbram to a backend
storage, such that field-programmed values in one
invocation can be made available to next invocation.

The backend storage must be a seekable binary file, and
its size must be 36 bytes or larger. A file with all
binary 0's is a 'blank'.

Signed-off-by: Tong Ho <tong.ho@xilinx.com>
Message-id: 20210917052400.1249094-8-tong.ho@xilinx.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/hw/arm/xlnx-zcu102.c b/hw/arm/xlnx-zcu102.c
index 6c6cb02e86..b247c5779b 100644
--- a/hw/arm/xlnx-zcu102.c
+++ b/hw/arm/xlnx-zcu102.c
@@ -98,6 +98,18 @@ static void zcu102_modify_dtb(const struct arm_boot_info *binfo, void *fdt)
     }
 }
 
+static void bbram_attach_drive(XlnxBBRam *dev)
+{
+    DriveInfo *dinfo;
+    BlockBackend *blk;
+
+    dinfo = drive_get_by_index(IF_PFLASH, 2);
+    blk = dinfo ? blk_by_legacy_dinfo(dinfo) : NULL;
+    if (blk) {
+        qdev_prop_set_drive(DEVICE(dev), "drive", blk);
+    }
+}
+
 static void xlnx_zcu102_init(MachineState *machine)
 {
     XlnxZCU102 *s = ZCU102_MACHINE(machine);
@@ -136,6 +148,9 @@ static void xlnx_zcu102_init(MachineState *machine)
 
     qdev_realize(DEVICE(&s->soc), NULL, &error_fatal);
 
+    /* Attach bbram backend, if given */
+    bbram_attach_drive(&s->soc.bbram);
+
     /* Create and plug in the SD cards */
     for (i = 0; i < XLNX_ZYNQMP_NUM_SDHCI; i++) {
         BusState *bus;