[PATCH 07/11] hw/ppc/e500: Implement pflash handling

[Bernhard Beschow <shentey@gmail.com>]

Allows e500 boards to have their root file system reside on flash using
only builtin devices.

Note that the flash memory area is only created when a -pflash argument is
given, and that the size is determined by the given file. The idea is to
put users into control.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 docs/system/ppc/ppce500.rst | 12 +++++++++
 hw/ppc/Kconfig              |  1 +
 hw/ppc/e500.c               | 54 +++++++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)

diff --git a/docs/system/ppc/ppce500.rst b/docs/system/ppc/ppce500.rst
index ba6bcb7314..c3f55c6f3d 100644
--- a/docs/system/ppc/ppce500.rst
+++ b/docs/system/ppc/ppce500.rst
@@ -119,6 +119,18 @@ To boot the 32-bit Linux kernel:
       -initrd /path/to/rootfs.cpio \
       -append "root=/dev/ram"
 
+Rather than using a root file system on ram disk, it is possible to have it on
+emulated flash. Given an ext2 image whose size must be a power of two, it can
+be used as follows:
+
+.. code-block:: bash
+
+  $ qemu-system-ppc64 -M ppce500 -cpu e500mc -smp 4 -m 2G \
+      -display none -serial stdio \
+      -kernel vmlinux \
+      -drive if=pflash,file=/path/to/rootfs.ext2,format=raw \
+      -append "rootwait root=/dev/mtdblock0"
+
 Running U-Boot
 --------------
 
diff --git a/hw/ppc/Kconfig b/hw/ppc/Kconfig
index 791fe78a50..769a1ead1c 100644
--- a/hw/ppc/Kconfig
+++ b/hw/ppc/Kconfig
@@ -126,6 +126,7 @@ config E500
     select ETSEC
     select GPIO_MPC8XXX
     select OPENPIC
+    select PFLASH_CFI01
     select PLATFORM_BUS
     select PPCE500_PCI
     select SERIAL
diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
index 864b6f3d92..7843a4e04b 100644
--- a/hw/ppc/e500.c
+++ b/hw/ppc/e500.c
@@ -23,8 +23,10 @@
 #include "e500-ccsr.h"
 #include "net/net.h"
 #include "qemu/config-file.h"
+#include "hw/block/flash.h"
 #include "hw/char/serial.h"
 #include "hw/pci/pci.h"
+#include "sysemu/block-backend-io.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/kvm.h"
 #include "sysemu/reset.h"
@@ -267,6 +269,34 @@ static void sysbus_device_create_devtree(SysBusDevice *sbdev, void *opaque)
     }
 }
 
+static void create_devtree_flash(SysBusDevice *sbdev,
+                                 PlatformDevtreeData *data)
+{
+    char *name;
+    uint64_t num_blocks = object_property_get_uint(OBJECT(sbdev),
+                                                   "num-blocks",
+                                                   &error_fatal);
+    uint64_t sector_length = object_property_get_uint(OBJECT(sbdev),
+                                                      "sector-length",
+                                                      &error_fatal);
+    uint64_t bank_width = object_property_get_uint(OBJECT(sbdev),
+                                                   "width",
+                                                   &error_fatal);
+    hwaddr flashbase = 0;
+    hwaddr flashsize = num_blocks * sector_length;
+    void *fdt = data->fdt;
+
+    name = g_strdup_printf("%s/nor@%" PRIx64, data->node, flashbase);
+    qemu_fdt_add_subnode(fdt, name);
+    qemu_fdt_setprop_cell(fdt, name, "#address-cells", 1);
+    qemu_fdt_setprop_cell(fdt, name, "#size-cells", 1);
+    qemu_fdt_setprop_string(fdt, name, "compatible", "cfi-flash");
+    qemu_fdt_setprop_sized_cells(fdt, name, "reg",
+                                 1, flashbase, 1, flashsize);
+    qemu_fdt_setprop_cell(fdt, name, "bank-width", bank_width);
+    g_free(name);
+}
+
 static void platform_bus_create_devtree(PPCE500MachineState *pms,
                                         void *fdt, const char *mpic)
 {
@@ -276,6 +306,8 @@ static void platform_bus_create_devtree(PPCE500MachineState *pms,
     uint64_t addr = pmc->platform_bus_base;
     uint64_t size = pmc->platform_bus_size;
     int irq_start = pmc->platform_bus_first_irq;
+    SysBusDevice *sbdev;
+    bool ambiguous;
 
     /* Create a /platform node that we can put all devices into */
 
@@ -302,6 +334,13 @@ static void platform_bus_create_devtree(PPCE500MachineState *pms,
     /* Loop through all dynamic sysbus devices and create nodes for them */
     foreach_dynamic_sysbus_device(sysbus_device_create_devtree, &data);
 
+    sbdev = SYS_BUS_DEVICE(object_resolve_path_type("", TYPE_PFLASH_CFI01,
+                                                    &ambiguous));
+    if (sbdev) {
+        assert(!ambiguous);
+        create_devtree_flash(sbdev, &data);
+    }
+
     g_free(node);
 }
 
@@ -856,6 +895,7 @@ void ppce500_init(MachineState *machine)
     unsigned int pci_irq_nrs[PCI_NUM_PINS] = {1, 2, 3, 4};
     IrqLines *irqs;
     DeviceState *dev, *mpicdev;
+    DriveInfo *dinfo;
     CPUPPCState *firstenv = NULL;
     MemoryRegion *ccsr_addr_space;
     SysBusDevice *s;
@@ -1024,6 +1064,20 @@ void ppce500_init(MachineState *machine)
                                 pmc->platform_bus_base,
                                 sysbus_mmio_get_region(s, 0));
 
+    dinfo = drive_get(IF_PFLASH, 0, 0);
+    if (dinfo) {
+        BlockBackend *blk = blk_by_legacy_dinfo(dinfo);
+        BlockDriverState *bs = blk_bs(blk);
+        uint64_t size = bdrv_getlength(bs);
+        if (ctpop64(size) != 1) {
+            error_report("Size of pflash file must be a power of two.");
+            exit(1);
+        }
+        pflash_cfi01_register(pmc->platform_bus_base, "e500.flash",
+                              size, blk,
+                              64 * KiB, 2, 0x89, 0x18, 0x0000, 0x0, 1);
+    }
+
     /*
      * Smart firmware defaults ahead!
      *
-- 
2.37.3