hw/arm/xilinx_zynq: Replace drive_get_next() by drive_get()

drive_get_next() is basically a bad idea.  It returns the "next" block
backend of a certain interface type.  "Next" means bus=0,unit=N, where
subsequent calls count N up from zero, per interface type.

This lets you define unit numbers implicitly by execution order.  If the
order changes, or new calls appear "in the middle", unit numbers change.
ABI break.  Hard to spot in review.

Machine "xlnx-zcu102" connects backends with drive_get_next() in two
counting loops, one of them in a helper function.  Change it to use
drive_get() directly.  This makes the unit numbers explicit in the
code.

Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
Cc: Alistair Francis <alistair@alistair23.me>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-arm@nongnu.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20211117163409.3587705-12-armbru@redhat.com>
Acked-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>

hw/arm/xilinx_zynq.c

@@ -125,9 +125,10 @@ static void gem_init(NICInfo *nd, uint32_t base, qemu_irq irq)
     sysbus_connect_irq(s, 0, irq);
 }
 
-static inline void zynq_init_spi_flashes(uint32_t base_addr, qemu_irq irq,
-                                         bool is_qspi)
+static inline int zynq_init_spi_flashes(uint32_t base_addr, qemu_irq irq,
+                                        bool is_qspi, int unit0)
 {
+    int unit = unit0;
     DeviceState *dev;
     SysBusDevice *busdev;
     SSIBus *spi;
@@ -156,7 +157,7 @@ static inline void zynq_init_spi_flashes(uint32_t base_addr, qemu_irq irq,
         spi = (SSIBus *)qdev_get_child_bus(dev, bus_name);
 
         for (j = 0; j < num_ss; ++j) {
-            DriveInfo *dinfo = drive_get_next(IF_MTD);
+            DriveInfo *dinfo = drive_get(IF_MTD, 0, unit++);
             flash_dev = qdev_new("n25q128");
             if (dinfo) {
                 qdev_prop_set_drive_err(flash_dev, "drive",
@@ -170,6 +171,7 @@ static inline void zynq_init_spi_flashes(uint32_t base_addr, qemu_irq irq,
         }
     }
 
+    return unit;
 }
 
 static void zynq_init(MachineState *machine)
@@ -247,9 +249,9 @@ static void zynq_init(MachineState *machine)
         pic[n] = qdev_get_gpio_in(dev, n);
     }
 
-    zynq_init_spi_flashes(0xE0006000, pic[58-IRQ_OFFSET], false);
-    zynq_init_spi_flashes(0xE0007000, pic[81-IRQ_OFFSET], false);
-    zynq_init_spi_flashes(0xE000D000, pic[51-IRQ_OFFSET], true);
+    n = zynq_init_spi_flashes(0xE0006000, pic[58 - IRQ_OFFSET], false, 0);
+    n = zynq_init_spi_flashes(0xE0007000, pic[81 - IRQ_OFFSET], false, n);
+    n = zynq_init_spi_flashes(0xE000D000, pic[51 - IRQ_OFFSET], true, n);
 
     sysbus_create_simple(TYPE_CHIPIDEA, 0xE0002000, pic[53 - IRQ_OFFSET]);
     sysbus_create_simple(TYPE_CHIPIDEA, 0xE0003000, pic[76 - IRQ_OFFSET]);
@@ -298,7 +300,7 @@ static void zynq_init(MachineState *machine)
         sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, hci_addr);
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, pic[hci_irq - IRQ_OFFSET]);
 
-        di = drive_get_next(IF_SD);
+        di = drive_get(IF_SD, 0, n);
         blk = di ? blk_by_legacy_dinfo(di) : NULL;
         carddev = qdev_new(TYPE_SD_CARD);
         qdev_prop_set_drive_err(carddev, "drive", blk, &error_fatal);