aspeed: create mapping regions for the maximum number of slaves

The SMC controller on the Aspeed SoC has a set of registers to
configure the mapping of each flash module in the SoC address
space. These mapping windows are configurable even though no SPI slave
is attached to the controller.

Also rewrite a bit the comments in the code on this topic.
Signed-off-by: NCédric Le Goater <clg@kaod.org>
Reviewed-by: NAndrew Jeffery <andrew@aj.id.au>
Message-id: 1474977462-28032-6-git-send-email-clg@kaod.org
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/ssi/aspeed_smc.c

@@ -417,12 +417,15 @@ static void aspeed_smc_realize(DeviceState *dev, Error **errp)
 
     aspeed_smc_reset(dev);
 
+    /* The memory region for the controller registers */
     memory_region_init_io(&s->mmio, OBJECT(s), &aspeed_smc_ops, s,
                           s->ctrl->name, ASPEED_SMC_R_MAX * 4);
     sysbus_init_mmio(sbd, &s->mmio);
 
     /*
-     * Memory region where flash modules are remapped
+     * The container memory region representing the address space
+     * window in which the flash modules are mapped. The size and
+     * address depends on the SoC model and controller type.
      */
     snprintf(name, sizeof(name), "%s.flash", s->ctrl->name);
 
@@ -431,9 +434,16 @@ static void aspeed_smc_realize(DeviceState *dev, Error **errp)
                           s->ctrl->flash_window_size);
     sysbus_init_mmio(sbd, &s->mmio_flash);
 
-    s->flashes = g_new0(AspeedSMCFlash, s->num_cs);
+    s->flashes = g_new0(AspeedSMCFlash, s->ctrl->max_slaves);
 
-    for (i = 0; i < s->num_cs; ++i) {
+    /*
+     * Let's create a sub memory region for each possible slave. All
+     * have a configurable memory segment in the overall flash mapping
+     * window of the controller but, there is not necessarily a flash
+     * module behind to handle the memory accesses. This depends on
+     * the board configuration.
+     */
+    for (i = 0; i < s->ctrl->max_slaves; ++i) {
         AspeedSMCFlash *fl = &s->flashes[i];
 
         snprintf(name, sizeof(name), "%s.%d", s->ctrl->name, i);