ppc/pnv: add a ISA bus

As Qemu only supports a single instance of the ISA bus, we use the LPC
controller of chip 0 to create one and plug in a couple of useful
devices, like an UART and RTC. An IPMI BT device, which is also an ISA
device, can be defined on the command line to connect an external BMC.
That is for later.

The PowerNV machine now has a console. Skiboot should load a kernel
and jump into it but execution will stop quite early because we lack a
model for the native XICS controller for the moment :

    [    0.000000] NR_IRQS:512 nr_irqs:512 16
    [    0.000000] XICS: Cannot find a Presentation Controller !
    [    0.000000] ------------[ cut here ]------------
    [    0.000000] WARNING: at arch/powerpc/platforms/powernv/setup.c:81
    ...
    [    0.000000] NIP [c00000000079d65c] pnv_init_IRQ+0x30/0x44

You can still do a few things under xmon.

Based on previous work from :
      Benjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
[dwg: Trivial fix for a change in the serial_hds_isa_init() interface]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

2 files changed, 67 insertions, 0 deletions

diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index aa712fd6f5..82276e0857 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -35,6 +35,10 @@
 
 #include "hw/ppc/pnv_xscom.h"
 
+#include "hw/isa/isa.h"
+#include "hw/char/serial.h"
+#include "hw/timer/mc146818rtc.h"
+
 #include <libfdt.h>
 
 #define FDT_MAX_SIZE            0x00100000
@@ -301,6 +305,58 @@ static void ppc_powernv_reset(void)
     cpu_physical_memory_write(PNV_FDT_ADDR, fdt, fdt_totalsize(fdt));
 }
 
+/* If we don't use the built-in LPC interrupt deserializer, we need
+ * to provide a set of qirqs for the ISA bus or things will go bad.
+ *
+ * Most machines using pre-Naples chips (without said deserializer)
+ * have a CPLD that will collect the SerIRQ and shoot them as a
+ * single level interrupt to the P8 chip. So let's setup a hook
+ * for doing just that.
+ *
+ * Note: The actual interrupt input isn't emulated yet, this will
+ * come with the PSI bridge model.
+ */
+static void pnv_lpc_isa_irq_handler_cpld(void *opaque, int n, int level)
+{
+    /* We don't yet emulate the PSI bridge which provides the external
+     * interrupt, so just drop interrupts on the floor
+     */
+}
+
+static void pnv_lpc_isa_irq_handler(void *opaque, int n, int level)
+{
+     /* XXX TODO */
+}
+
+static ISABus *pnv_isa_create(PnvChip *chip)
+{
+    PnvLpcController *lpc = &chip->lpc;
+    ISABus *isa_bus;
+    qemu_irq *irqs;
+    PnvChipClass *pcc = PNV_CHIP_GET_CLASS(chip);
+
+    /* let isa_bus_new() create its own bridge on SysBus otherwise
+     * devices speficied on the command line won't find the bus and
+     * will fail to create.
+     */
+    isa_bus = isa_bus_new(NULL, &lpc->isa_mem, &lpc->isa_io,
+                          &error_fatal);
+
+    /* Not all variants have a working serial irq decoder. If not,
+     * handling of LPC interrupts becomes a platform issue (some
+     * platforms have a CPLD to do it).
+     */
+    if (pcc->chip_type == PNV_CHIP_POWER8NVL) {
+        irqs = qemu_allocate_irqs(pnv_lpc_isa_irq_handler, chip, ISA_NUM_IRQS);
+    } else {
+        irqs = qemu_allocate_irqs(pnv_lpc_isa_irq_handler_cpld, chip,
+                                  ISA_NUM_IRQS);
+    }
+
+    isa_bus_irqs(isa_bus, irqs);
+    return isa_bus;
+}
+
 static void ppc_powernv_init(MachineState *machine)
 {
     PnvMachineState *pnv = POWERNV_MACHINE(machine);
@@ -395,6 +451,15 @@ static void ppc_powernv_init(MachineState *machine)
         object_property_set_bool(chip, true, "realized", &error_fatal);
     }
     g_free(chip_typename);
+
+    /* Instantiate ISA bus on chip 0 */
+    pnv->isa_bus = pnv_isa_create(pnv->chips[0]);
+
+    /* Create serial port */
+    serial_hds_isa_init(pnv->isa_bus, 0, MAX_SERIAL_PORTS);
+
+    /* Create an RTC ISA device too */
+    rtc_init(pnv->isa_bus, 2000, NULL);
 }
 
 /*
diff --git a/include/hw/ppc/pnv.h b/include/hw/ppc/pnv.h
index ce16e47724..02ac1c5f42 100644
--- a/include/hw/ppc/pnv.h
+++ b/include/hw/ppc/pnv.h
@@ -112,6 +112,8 @@ typedef struct PnvMachineState {
 
     uint32_t     num_chips;
     PnvChip      **chips;
+
+    ISABus       *isa_bus;
 } PnvMachineState;
 
 #define PNV_FDT_ADDR          0x01000000