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>

hw/Kconfig

@@ -81,3 +81,4 @@ config XLNX_ZYNQMP
     select REGISTER
     select CAN_BUS
     select PTIMER
+    select XLNX_BBRAM

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;

hw/arm/xlnx-zynqmp.c

@@ -66,6 +66,9 @@
 #define RTC_ADDR            0xffa60000
 #define RTC_IRQ             26
 
+#define BBRAM_ADDR          0xffcd0000
+#define BBRAM_IRQ           11
+
 #define SDHCI_CAPABILITIES  0x280737ec6481 /* Datasheet: UG1085 (v1.7) */
 
 static const uint64_t gem_addr[XLNX_ZYNQMP_NUM_GEMS] = {
@@ -226,6 +229,22 @@ static void xlnx_zynqmp_create_rpu(MachineState *ms, XlnxZynqMPState *s,
     qdev_realize(DEVICE(&s->rpu_cluster), NULL, &error_fatal);
 }
 
+static void xlnx_zynqmp_create_bbram(XlnxZynqMPState *s, qemu_irq *gic)
+{
+    SysBusDevice *sbd;
+
+    object_initialize_child_with_props(OBJECT(s), "bbram", &s->bbram,
+                                       sizeof(s->bbram), TYPE_XLNX_BBRAM,
+                                       &error_fatal,
+                                       "crc-zpads", "1",
+                                       NULL);
+    sbd = SYS_BUS_DEVICE(&s->bbram);
+
+    sysbus_realize(sbd, &error_fatal);
+    sysbus_mmio_map(sbd, 0, BBRAM_ADDR);
+    sysbus_connect_irq(sbd, 0, gic[BBRAM_IRQ]);
+}
+
 static void xlnx_zynqmp_create_unimp_mmio(XlnxZynqMPState *s)
 {
     static const struct UnimpInfo {
@@ -626,6 +645,7 @@ static void xlnx_zynqmp_realize(DeviceState *dev, Error **errp)
     sysbus_mmio_map(SYS_BUS_DEVICE(&s->rtc), 0, RTC_ADDR);
     sysbus_connect_irq(SYS_BUS_DEVICE(&s->rtc), 0, gic_spi[RTC_IRQ]);
 
+    xlnx_zynqmp_create_bbram(s, gic_spi);
     xlnx_zynqmp_create_unimp_mmio(s);
 
     for (i = 0; i < XLNX_ZYNQMP_NUM_GDMA_CH; i++) {

include/hw/arm/xlnx-zynqmp.h

@@ -36,6 +36,7 @@
 #include "qom/object.h"
 #include "net/can_emu.h"
 #include "hw/dma/xlnx_csu_dma.h"
+#include "hw/nvram/xlnx-bbram.h"
 
 #define TYPE_XLNX_ZYNQMP "xlnx-zynqmp"
 OBJECT_DECLARE_SIMPLE_TYPE(XlnxZynqMPState, XLNX_ZYNQMP)
@@ -100,6 +101,7 @@ struct XlnxZynqMPState {
 
     MemoryRegion *ddr_ram;
     MemoryRegion ddr_ram_low, ddr_ram_high;
+    XlnxBBRam bbram;
 
     MemoryRegion mr_unimp[XLNX_ZYNQMP_NUM_UNIMP_AREAS];