hw/arm: xlnx-versal-virt: Add Xilinx BBRAM device

Connect the support for Versal Battery-Backed RAM (BBRAM)

The command argument:
  -drive if=pflash,index=0,...
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: 20210917052400.1249094-6-tong.ho@xilinx.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 55 insertions, 0 deletions

diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
index 18832ab..d35ded9 100644
--- a/hw/arm/Kconfig
+++ b/hw/arm/Kconfig
@@ -381,6 +381,7 @@ config XLNX_VERSAL
     select XLNX_ZDMA
     select XLNX_ZYNQMP
     select OR_IRQ
+    select XLNX_BBRAM
 
 config NPCM7XX
     bool
diff --git a/hw/arm/xlnx-versal-virt.c b/hw/arm/xlnx-versal-virt.c
index 5bca360..e1c5ead 100644
--- a/hw/arm/xlnx-versal-virt.c
+++ b/hw/arm/xlnx-versal-virt.c
@@ -356,6 +356,26 @@ static void fdt_add_rtc_node(VersalVirt *s)
     g_free(name);
 }
 
+static void fdt_add_bbram_node(VersalVirt *s)
+{
+    const char compat[] = TYPE_XLNX_BBRAM;
+    const char interrupt_names[] = "bbram-error";
+    char *name = g_strdup_printf("/bbram@%x", MM_PMC_BBRAM_CTRL);
+
+    qemu_fdt_add_subnode(s->fdt, name);
+
+    qemu_fdt_setprop_cells(s->fdt, name, "interrupts",
+                           GIC_FDT_IRQ_TYPE_SPI, VERSAL_BBRAM_APB_IRQ_0,
+                           GIC_FDT_IRQ_FLAGS_LEVEL_HI);
+    qemu_fdt_setprop(s->fdt, name, "interrupt-names",
+                     interrupt_names, sizeof(interrupt_names));
+    qemu_fdt_setprop_sized_cells(s->fdt, name, "reg",
+                                 2, MM_PMC_BBRAM_CTRL,
+                                 2, MM_PMC_BBRAM_CTRL_SIZE);
+    qemu_fdt_setprop(s->fdt, name, "compatible", compat, sizeof(compat));
+    g_free(name);
+}
+
 static void fdt_nop_memory_nodes(void *fdt, Error **errp)
 {
     Error *err = NULL;
@@ -510,6 +530,18 @@ static void create_virtio_regions(VersalVirt *s)
     }
 }
 
+static void bbram_attach_drive(XlnxBBRam *dev)
+{
+    DriveInfo *dinfo;
+    BlockBackend *blk;
+
+    dinfo = drive_get_by_index(IF_PFLASH, 0);
+    blk = dinfo ? blk_by_legacy_dinfo(dinfo) : NULL;
+    if (blk) {
+        qdev_prop_set_drive(DEVICE(dev), "drive", blk);
+    }
+}
+
 static void sd_plugin_card(SDHCIState *sd, DriveInfo *di)
 {
     BlockBackend *blk = di ? blk_by_legacy_dinfo(di) : NULL;
@@ -570,6 +602,7 @@ static void versal_virt_init(MachineState *machine)
     fdt_add_usb_xhci_nodes(s);
     fdt_add_sd_nodes(s);
     fdt_add_rtc_node(s);
+    fdt_add_bbram_node(s);
     fdt_add_cpu_nodes(s, psci_conduit);
     fdt_add_clk_node(s, "/clk125", 125000000, s->phandle.clk_125Mhz);
     fdt_add_clk_node(s, "/clk25", 25000000, s->phandle.clk_25Mhz);
@@ -579,6 +612,9 @@ static void versal_virt_init(MachineState *machine)
     memory_region_add_subregion_overlap(get_system_memory(),
                                         0, &s->soc.fpd.apu.mr, 0);
 
+    /* Attach bbram backend, if given */
+    bbram_attach_drive(&s->soc.pmc.bbram);
+
     /* Plugin SD cards.  */
     for (i = 0; i < ARRAY_SIZE(s->soc.pmc.iou.sd); i++) {
         sd_plugin_card(&s->soc.pmc.iou.sd[i], drive_get_next(IF_SD));
diff --git a/hw/arm/xlnx-versal.c b/hw/arm/xlnx-versal.c
index 547a266..23451ae 100644
--- a/hw/arm/xlnx-versal.c
+++ b/hw/arm/xlnx-versal.c
@@ -314,6 +314,23 @@ static void versal_create_xrams(Versal *s, qemu_irq *pic)
     }
 }
 
+static void versal_create_bbram(Versal *s, qemu_irq *pic)
+{
+    SysBusDevice *sbd;
+
+    object_initialize_child_with_props(OBJECT(s), "bbram", &s->pmc.bbram,
+                                       sizeof(s->pmc.bbram), TYPE_XLNX_BBRAM,
+                                       &error_fatal,
+                                       "crc-zpads", "0",
+                                       NULL);
+    sbd = SYS_BUS_DEVICE(&s->pmc.bbram);
+
+    sysbus_realize(sbd, &error_fatal);
+    memory_region_add_subregion(&s->mr_ps, MM_PMC_BBRAM_CTRL,
+                                sysbus_mmio_get_region(sbd, 0));
+    sysbus_connect_irq(sbd, 0, pic[VERSAL_BBRAM_APB_IRQ_0]);
+}
+
 /* This takes the board allocated linear DDR memory and creates aliases
  * for each split DDR range/aperture on the Versal address map.
  */
@@ -402,6 +419,7 @@ static void versal_realize(DeviceState *dev, Error **errp)
     versal_create_sds(s, pic);
     versal_create_rtc(s, pic);
     versal_create_xrams(s, pic);
+    versal_create_bbram(s, pic);
     versal_map_ddr(s);
     versal_unimp(s);