Add qemu 2.4.0
[kvmfornfv.git] / qemu / hw / ppc / ppc4xx_devs.c
diff --git a/qemu/hw/ppc/ppc4xx_devs.c b/qemu/hw/ppc/ppc4xx_devs.c
new file mode 100644 (file)
index 0000000..2f38ff7
--- /dev/null
@@ -0,0 +1,734 @@
+/*
+ * QEMU PowerPC 4xx embedded processors shared devices emulation
+ *
+ * Copyright (c) 2007 Jocelyn Mayer
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "hw/hw.h"
+#include "hw/ppc/ppc.h"
+#include "hw/ppc/ppc4xx.h"
+#include "hw/boards.h"
+#include "qemu/log.h"
+#include "exec/address-spaces.h"
+
+#define DEBUG_UIC
+
+
+#ifdef DEBUG_UIC
+#  define LOG_UIC(...) qemu_log_mask(CPU_LOG_INT, ## __VA_ARGS__)
+#else
+#  define LOG_UIC(...) do { } while (0)
+#endif
+
+static void ppc4xx_reset(void *opaque)
+{
+    PowerPCCPU *cpu = opaque;
+
+    cpu_reset(CPU(cpu));
+}
+
+/*****************************************************************************/
+/* Generic PowerPC 4xx processor instantiation */
+PowerPCCPU *ppc4xx_init(const char *cpu_model,
+                        clk_setup_t *cpu_clk, clk_setup_t *tb_clk,
+                        uint32_t sysclk)
+{
+    PowerPCCPU *cpu;
+    CPUPPCState *env;
+
+    /* init CPUs */
+    cpu = cpu_ppc_init(cpu_model);
+    if (cpu == NULL) {
+        fprintf(stderr, "Unable to find PowerPC %s CPU definition\n",
+                cpu_model);
+        exit(1);
+    }
+    env = &cpu->env;
+
+    cpu_clk->cb = NULL; /* We don't care about CPU clock frequency changes */
+    cpu_clk->opaque = env;
+    /* Set time-base frequency to sysclk */
+    tb_clk->cb = ppc_40x_timers_init(env, sysclk, PPC_INTERRUPT_PIT);
+    tb_clk->opaque = env;
+    ppc_dcr_init(env, NULL, NULL);
+    /* Register qemu callbacks */
+    qemu_register_reset(ppc4xx_reset, cpu);
+
+    return cpu;
+}
+
+/*****************************************************************************/
+/* "Universal" Interrupt controller */
+enum {
+    DCR_UICSR  = 0x000,
+    DCR_UICSRS = 0x001,
+    DCR_UICER  = 0x002,
+    DCR_UICCR  = 0x003,
+    DCR_UICPR  = 0x004,
+    DCR_UICTR  = 0x005,
+    DCR_UICMSR = 0x006,
+    DCR_UICVR  = 0x007,
+    DCR_UICVCR = 0x008,
+    DCR_UICMAX = 0x009,
+};
+
+#define UIC_MAX_IRQ 32
+typedef struct ppcuic_t ppcuic_t;
+struct ppcuic_t {
+    uint32_t dcr_base;
+    int use_vectors;
+    uint32_t level;  /* Remembers the state of level-triggered interrupts. */
+    uint32_t uicsr;  /* Status register */
+    uint32_t uicer;  /* Enable register */
+    uint32_t uiccr;  /* Critical register */
+    uint32_t uicpr;  /* Polarity register */
+    uint32_t uictr;  /* Triggering register */
+    uint32_t uicvcr; /* Vector configuration register */
+    uint32_t uicvr;
+    qemu_irq *irqs;
+};
+
+static void ppcuic_trigger_irq (ppcuic_t *uic)
+{
+    uint32_t ir, cr;
+    int start, end, inc, i;
+
+    /* Trigger interrupt if any is pending */
+    ir = uic->uicsr & uic->uicer & (~uic->uiccr);
+    cr = uic->uicsr & uic->uicer & uic->uiccr;
+    LOG_UIC("%s: uicsr %08" PRIx32 " uicer %08" PRIx32
+                " uiccr %08" PRIx32 "\n"
+                "   %08" PRIx32 " ir %08" PRIx32 " cr %08" PRIx32 "\n",
+                __func__, uic->uicsr, uic->uicer, uic->uiccr,
+                uic->uicsr & uic->uicer, ir, cr);
+    if (ir != 0x0000000) {
+        LOG_UIC("Raise UIC interrupt\n");
+        qemu_irq_raise(uic->irqs[PPCUIC_OUTPUT_INT]);
+    } else {
+        LOG_UIC("Lower UIC interrupt\n");
+        qemu_irq_lower(uic->irqs[PPCUIC_OUTPUT_INT]);
+    }
+    /* Trigger critical interrupt if any is pending and update vector */
+    if (cr != 0x0000000) {
+        qemu_irq_raise(uic->irqs[PPCUIC_OUTPUT_CINT]);
+        if (uic->use_vectors) {
+            /* Compute critical IRQ vector */
+            if (uic->uicvcr & 1) {
+                start = 31;
+                end = 0;
+                inc = -1;
+            } else {
+                start = 0;
+                end = 31;
+                inc = 1;
+            }
+            uic->uicvr = uic->uicvcr & 0xFFFFFFFC;
+            for (i = start; i <= end; i += inc) {
+                if (cr & (1 << i)) {
+                    uic->uicvr += (i - start) * 512 * inc;
+                    break;
+                }
+            }
+        }
+        LOG_UIC("Raise UIC critical interrupt - "
+                    "vector %08" PRIx32 "\n", uic->uicvr);
+    } else {
+        LOG_UIC("Lower UIC critical interrupt\n");
+        qemu_irq_lower(uic->irqs[PPCUIC_OUTPUT_CINT]);
+        uic->uicvr = 0x00000000;
+    }
+}
+
+static void ppcuic_set_irq (void *opaque, int irq_num, int level)
+{
+    ppcuic_t *uic;
+    uint32_t mask, sr;
+
+    uic = opaque;
+    mask = 1U << (31-irq_num);
+    LOG_UIC("%s: irq %d level %d uicsr %08" PRIx32
+                " mask %08" PRIx32 " => %08" PRIx32 " %08" PRIx32 "\n",
+                __func__, irq_num, level,
+                uic->uicsr, mask, uic->uicsr & mask, level << irq_num);
+    if (irq_num < 0 || irq_num > 31)
+        return;
+    sr = uic->uicsr;
+
+    /* Update status register */
+    if (uic->uictr & mask) {
+        /* Edge sensitive interrupt */
+        if (level == 1)
+            uic->uicsr |= mask;
+    } else {
+        /* Level sensitive interrupt */
+        if (level == 1) {
+            uic->uicsr |= mask;
+            uic->level |= mask;
+        } else {
+            uic->uicsr &= ~mask;
+            uic->level &= ~mask;
+        }
+    }
+    LOG_UIC("%s: irq %d level %d sr %" PRIx32 " => "
+                "%08" PRIx32 "\n", __func__, irq_num, level, uic->uicsr, sr);
+    if (sr != uic->uicsr)
+        ppcuic_trigger_irq(uic);
+}
+
+static uint32_t dcr_read_uic (void *opaque, int dcrn)
+{
+    ppcuic_t *uic;
+    uint32_t ret;
+
+    uic = opaque;
+    dcrn -= uic->dcr_base;
+    switch (dcrn) {
+    case DCR_UICSR:
+    case DCR_UICSRS:
+        ret = uic->uicsr;
+        break;
+    case DCR_UICER:
+        ret = uic->uicer;
+        break;
+    case DCR_UICCR:
+        ret = uic->uiccr;
+        break;
+    case DCR_UICPR:
+        ret = uic->uicpr;
+        break;
+    case DCR_UICTR:
+        ret = uic->uictr;
+        break;
+    case DCR_UICMSR:
+        ret = uic->uicsr & uic->uicer;
+        break;
+    case DCR_UICVR:
+        if (!uic->use_vectors)
+            goto no_read;
+        ret = uic->uicvr;
+        break;
+    case DCR_UICVCR:
+        if (!uic->use_vectors)
+            goto no_read;
+        ret = uic->uicvcr;
+        break;
+    default:
+    no_read:
+        ret = 0x00000000;
+        break;
+    }
+
+    return ret;
+}
+
+static void dcr_write_uic (void *opaque, int dcrn, uint32_t val)
+{
+    ppcuic_t *uic;
+
+    uic = opaque;
+    dcrn -= uic->dcr_base;
+    LOG_UIC("%s: dcr %d val 0x%x\n", __func__, dcrn, val);
+    switch (dcrn) {
+    case DCR_UICSR:
+        uic->uicsr &= ~val;
+        uic->uicsr |= uic->level;
+        ppcuic_trigger_irq(uic);
+        break;
+    case DCR_UICSRS:
+        uic->uicsr |= val;
+        ppcuic_trigger_irq(uic);
+        break;
+    case DCR_UICER:
+        uic->uicer = val;
+        ppcuic_trigger_irq(uic);
+        break;
+    case DCR_UICCR:
+        uic->uiccr = val;
+        ppcuic_trigger_irq(uic);
+        break;
+    case DCR_UICPR:
+        uic->uicpr = val;
+        break;
+    case DCR_UICTR:
+        uic->uictr = val;
+        ppcuic_trigger_irq(uic);
+        break;
+    case DCR_UICMSR:
+        break;
+    case DCR_UICVR:
+        break;
+    case DCR_UICVCR:
+        uic->uicvcr = val & 0xFFFFFFFD;
+        ppcuic_trigger_irq(uic);
+        break;
+    }
+}
+
+static void ppcuic_reset (void *opaque)
+{
+    ppcuic_t *uic;
+
+    uic = opaque;
+    uic->uiccr = 0x00000000;
+    uic->uicer = 0x00000000;
+    uic->uicpr = 0x00000000;
+    uic->uicsr = 0x00000000;
+    uic->uictr = 0x00000000;
+    if (uic->use_vectors) {
+        uic->uicvcr = 0x00000000;
+        uic->uicvr = 0x0000000;
+    }
+}
+
+qemu_irq *ppcuic_init (CPUPPCState *env, qemu_irq *irqs,
+                       uint32_t dcr_base, int has_ssr, int has_vr)
+{
+    ppcuic_t *uic;
+    int i;
+
+    uic = g_malloc0(sizeof(ppcuic_t));
+    uic->dcr_base = dcr_base;
+    uic->irqs = irqs;
+    if (has_vr)
+        uic->use_vectors = 1;
+    for (i = 0; i < DCR_UICMAX; i++) {
+        ppc_dcr_register(env, dcr_base + i, uic,
+                         &dcr_read_uic, &dcr_write_uic);
+    }
+    qemu_register_reset(ppcuic_reset, uic);
+
+    return qemu_allocate_irqs(&ppcuic_set_irq, uic, UIC_MAX_IRQ);
+}
+
+/*****************************************************************************/
+/* SDRAM controller */
+typedef struct ppc4xx_sdram_t ppc4xx_sdram_t;
+struct ppc4xx_sdram_t {
+    uint32_t addr;
+    int nbanks;
+    MemoryRegion containers[4]; /* used for clipping */
+    MemoryRegion *ram_memories;
+    hwaddr ram_bases[4];
+    hwaddr ram_sizes[4];
+    uint32_t besr0;
+    uint32_t besr1;
+    uint32_t bear;
+    uint32_t cfg;
+    uint32_t status;
+    uint32_t rtr;
+    uint32_t pmit;
+    uint32_t bcr[4];
+    uint32_t tr;
+    uint32_t ecccfg;
+    uint32_t eccesr;
+    qemu_irq irq;
+};
+
+enum {
+    SDRAM0_CFGADDR = 0x010,
+    SDRAM0_CFGDATA = 0x011,
+};
+
+/* XXX: TOFIX: some patches have made this code become inconsistent:
+ *      there are type inconsistencies, mixing hwaddr, target_ulong
+ *      and uint32_t
+ */
+static uint32_t sdram_bcr (hwaddr ram_base,
+                           hwaddr ram_size)
+{
+    uint32_t bcr;
+
+    switch (ram_size) {
+    case (4 * 1024 * 1024):
+        bcr = 0x00000000;
+        break;
+    case (8 * 1024 * 1024):
+        bcr = 0x00020000;
+        break;
+    case (16 * 1024 * 1024):
+        bcr = 0x00040000;
+        break;
+    case (32 * 1024 * 1024):
+        bcr = 0x00060000;
+        break;
+    case (64 * 1024 * 1024):
+        bcr = 0x00080000;
+        break;
+    case (128 * 1024 * 1024):
+        bcr = 0x000A0000;
+        break;
+    case (256 * 1024 * 1024):
+        bcr = 0x000C0000;
+        break;
+    default:
+        printf("%s: invalid RAM size " TARGET_FMT_plx "\n", __func__,
+               ram_size);
+        return 0x00000000;
+    }
+    bcr |= ram_base & 0xFF800000;
+    bcr |= 1;
+
+    return bcr;
+}
+
+static inline hwaddr sdram_base(uint32_t bcr)
+{
+    return bcr & 0xFF800000;
+}
+
+static target_ulong sdram_size (uint32_t bcr)
+{
+    target_ulong size;
+    int sh;
+
+    sh = (bcr >> 17) & 0x7;
+    if (sh == 7)
+        size = -1;
+    else
+        size = (4 * 1024 * 1024) << sh;
+
+    return size;
+}
+
+static void sdram_set_bcr(ppc4xx_sdram_t *sdram,
+                          uint32_t *bcrp, uint32_t bcr, int enabled)
+{
+    unsigned n = bcrp - sdram->bcr;
+
+    if (*bcrp & 0x00000001) {
+        /* Unmap RAM */
+#ifdef DEBUG_SDRAM
+        printf("%s: unmap RAM area " TARGET_FMT_plx " " TARGET_FMT_lx "\n",
+               __func__, sdram_base(*bcrp), sdram_size(*bcrp));
+#endif
+        memory_region_del_subregion(get_system_memory(),
+                                    &sdram->containers[n]);
+        memory_region_del_subregion(&sdram->containers[n],
+                                    &sdram->ram_memories[n]);
+        object_unparent(OBJECT(&sdram->containers[n]));
+    }
+    *bcrp = bcr & 0xFFDEE001;
+    if (enabled && (bcr & 0x00000001)) {
+#ifdef DEBUG_SDRAM
+        printf("%s: Map RAM area " TARGET_FMT_plx " " TARGET_FMT_lx "\n",
+               __func__, sdram_base(bcr), sdram_size(bcr));
+#endif
+        memory_region_init(&sdram->containers[n], NULL, "sdram-containers",
+                           sdram_size(bcr));
+        memory_region_add_subregion(&sdram->containers[n], 0,
+                                    &sdram->ram_memories[n]);
+        memory_region_add_subregion(get_system_memory(),
+                                    sdram_base(bcr),
+                                    &sdram->containers[n]);
+    }
+}
+
+static void sdram_map_bcr (ppc4xx_sdram_t *sdram)
+{
+    int i;
+
+    for (i = 0; i < sdram->nbanks; i++) {
+        if (sdram->ram_sizes[i] != 0) {
+            sdram_set_bcr(sdram,
+                          &sdram->bcr[i],
+                          sdram_bcr(sdram->ram_bases[i], sdram->ram_sizes[i]),
+                          1);
+        } else {
+            sdram_set_bcr(sdram, &sdram->bcr[i], 0x00000000, 0);
+        }
+    }
+}
+
+static void sdram_unmap_bcr (ppc4xx_sdram_t *sdram)
+{
+    int i;
+
+    for (i = 0; i < sdram->nbanks; i++) {
+#ifdef DEBUG_SDRAM
+        printf("%s: Unmap RAM area " TARGET_FMT_plx " " TARGET_FMT_lx "\n",
+               __func__, sdram_base(sdram->bcr[i]), sdram_size(sdram->bcr[i]));
+#endif
+        memory_region_del_subregion(get_system_memory(),
+                                    &sdram->ram_memories[i]);
+    }
+}
+
+static uint32_t dcr_read_sdram (void *opaque, int dcrn)
+{
+    ppc4xx_sdram_t *sdram;
+    uint32_t ret;
+
+    sdram = opaque;
+    switch (dcrn) {
+    case SDRAM0_CFGADDR:
+        ret = sdram->addr;
+        break;
+    case SDRAM0_CFGDATA:
+        switch (sdram->addr) {
+        case 0x00: /* SDRAM_BESR0 */
+            ret = sdram->besr0;
+            break;
+        case 0x08: /* SDRAM_BESR1 */
+            ret = sdram->besr1;
+            break;
+        case 0x10: /* SDRAM_BEAR */
+            ret = sdram->bear;
+            break;
+        case 0x20: /* SDRAM_CFG */
+            ret = sdram->cfg;
+            break;
+        case 0x24: /* SDRAM_STATUS */
+            ret = sdram->status;
+            break;
+        case 0x30: /* SDRAM_RTR */
+            ret = sdram->rtr;
+            break;
+        case 0x34: /* SDRAM_PMIT */
+            ret = sdram->pmit;
+            break;
+        case 0x40: /* SDRAM_B0CR */
+            ret = sdram->bcr[0];
+            break;
+        case 0x44: /* SDRAM_B1CR */
+            ret = sdram->bcr[1];
+            break;
+        case 0x48: /* SDRAM_B2CR */
+            ret = sdram->bcr[2];
+            break;
+        case 0x4C: /* SDRAM_B3CR */
+            ret = sdram->bcr[3];
+            break;
+        case 0x80: /* SDRAM_TR */
+            ret = -1; /* ? */
+            break;
+        case 0x94: /* SDRAM_ECCCFG */
+            ret = sdram->ecccfg;
+            break;
+        case 0x98: /* SDRAM_ECCESR */
+            ret = sdram->eccesr;
+            break;
+        default: /* Error */
+            ret = -1;
+            break;
+        }
+        break;
+    default:
+        /* Avoid gcc warning */
+        ret = 0x00000000;
+        break;
+    }
+
+    return ret;
+}
+
+static void dcr_write_sdram (void *opaque, int dcrn, uint32_t val)
+{
+    ppc4xx_sdram_t *sdram;
+
+    sdram = opaque;
+    switch (dcrn) {
+    case SDRAM0_CFGADDR:
+        sdram->addr = val;
+        break;
+    case SDRAM0_CFGDATA:
+        switch (sdram->addr) {
+        case 0x00: /* SDRAM_BESR0 */
+            sdram->besr0 &= ~val;
+            break;
+        case 0x08: /* SDRAM_BESR1 */
+            sdram->besr1 &= ~val;
+            break;
+        case 0x10: /* SDRAM_BEAR */
+            sdram->bear = val;
+            break;
+        case 0x20: /* SDRAM_CFG */
+            val &= 0xFFE00000;
+            if (!(sdram->cfg & 0x80000000) && (val & 0x80000000)) {
+#ifdef DEBUG_SDRAM
+                printf("%s: enable SDRAM controller\n", __func__);
+#endif
+                /* validate all RAM mappings */
+                sdram_map_bcr(sdram);
+                sdram->status &= ~0x80000000;
+            } else if ((sdram->cfg & 0x80000000) && !(val & 0x80000000)) {
+#ifdef DEBUG_SDRAM
+                printf("%s: disable SDRAM controller\n", __func__);
+#endif
+                /* invalidate all RAM mappings */
+                sdram_unmap_bcr(sdram);
+                sdram->status |= 0x80000000;
+            }
+            if (!(sdram->cfg & 0x40000000) && (val & 0x40000000))
+                sdram->status |= 0x40000000;
+            else if ((sdram->cfg & 0x40000000) && !(val & 0x40000000))
+                sdram->status &= ~0x40000000;
+            sdram->cfg = val;
+            break;
+        case 0x24: /* SDRAM_STATUS */
+            /* Read-only register */
+            break;
+        case 0x30: /* SDRAM_RTR */
+            sdram->rtr = val & 0x3FF80000;
+            break;
+        case 0x34: /* SDRAM_PMIT */
+            sdram->pmit = (val & 0xF8000000) | 0x07C00000;
+            break;
+        case 0x40: /* SDRAM_B0CR */
+            sdram_set_bcr(sdram, &sdram->bcr[0], val, sdram->cfg & 0x80000000);
+            break;
+        case 0x44: /* SDRAM_B1CR */
+            sdram_set_bcr(sdram, &sdram->bcr[1], val, sdram->cfg & 0x80000000);
+            break;
+        case 0x48: /* SDRAM_B2CR */
+            sdram_set_bcr(sdram, &sdram->bcr[2], val, sdram->cfg & 0x80000000);
+            break;
+        case 0x4C: /* SDRAM_B3CR */
+            sdram_set_bcr(sdram, &sdram->bcr[3], val, sdram->cfg & 0x80000000);
+            break;
+        case 0x80: /* SDRAM_TR */
+            sdram->tr = val & 0x018FC01F;
+            break;
+        case 0x94: /* SDRAM_ECCCFG */
+            sdram->ecccfg = val & 0x00F00000;
+            break;
+        case 0x98: /* SDRAM_ECCESR */
+            val &= 0xFFF0F000;
+            if (sdram->eccesr == 0 && val != 0)
+                qemu_irq_raise(sdram->irq);
+            else if (sdram->eccesr != 0 && val == 0)
+                qemu_irq_lower(sdram->irq);
+            sdram->eccesr = val;
+            break;
+        default: /* Error */
+            break;
+        }
+        break;
+    }
+}
+
+static void sdram_reset (void *opaque)
+{
+    ppc4xx_sdram_t *sdram;
+
+    sdram = opaque;
+    sdram->addr = 0x00000000;
+    sdram->bear = 0x00000000;
+    sdram->besr0 = 0x00000000; /* No error */
+    sdram->besr1 = 0x00000000; /* No error */
+    sdram->cfg = 0x00000000;
+    sdram->ecccfg = 0x00000000; /* No ECC */
+    sdram->eccesr = 0x00000000; /* No error */
+    sdram->pmit = 0x07C00000;
+    sdram->rtr = 0x05F00000;
+    sdram->tr = 0x00854009;
+    /* We pre-initialize RAM banks */
+    sdram->status = 0x00000000;
+    sdram->cfg = 0x00800000;
+}
+
+void ppc4xx_sdram_init (CPUPPCState *env, qemu_irq irq, int nbanks,
+                        MemoryRegion *ram_memories,
+                        hwaddr *ram_bases,
+                        hwaddr *ram_sizes,
+                        int do_init)
+{
+    ppc4xx_sdram_t *sdram;
+
+    sdram = g_malloc0(sizeof(ppc4xx_sdram_t));
+    sdram->irq = irq;
+    sdram->nbanks = nbanks;
+    sdram->ram_memories = ram_memories;
+    memset(sdram->ram_bases, 0, 4 * sizeof(hwaddr));
+    memcpy(sdram->ram_bases, ram_bases,
+           nbanks * sizeof(hwaddr));
+    memset(sdram->ram_sizes, 0, 4 * sizeof(hwaddr));
+    memcpy(sdram->ram_sizes, ram_sizes,
+           nbanks * sizeof(hwaddr));
+    qemu_register_reset(&sdram_reset, sdram);
+    ppc_dcr_register(env, SDRAM0_CFGADDR,
+                     sdram, &dcr_read_sdram, &dcr_write_sdram);
+    ppc_dcr_register(env, SDRAM0_CFGDATA,
+                     sdram, &dcr_read_sdram, &dcr_write_sdram);
+    if (do_init)
+        sdram_map_bcr(sdram);
+}
+
+/* Fill in consecutive SDRAM banks with 'ram_size' bytes of memory.
+ *
+ * sdram_bank_sizes[] must be 0-terminated.
+ *
+ * The 4xx SDRAM controller supports a small number of banks, and each bank
+ * must be one of a small set of sizes. The number of banks and the supported
+ * sizes varies by SoC. */
+ram_addr_t ppc4xx_sdram_adjust(ram_addr_t ram_size, int nr_banks,
+                               MemoryRegion ram_memories[],
+                               hwaddr ram_bases[],
+                               hwaddr ram_sizes[],
+                               const unsigned int sdram_bank_sizes[])
+{
+    MemoryRegion *ram = g_malloc0(sizeof(*ram));
+    ram_addr_t size_left = ram_size;
+    ram_addr_t base = 0;
+    unsigned int bank_size;
+    int i;
+    int j;
+
+    for (i = 0; i < nr_banks; i++) {
+        for (j = 0; sdram_bank_sizes[j] != 0; j++) {
+            bank_size = sdram_bank_sizes[j];
+            if (bank_size <= size_left) {
+                size_left -= bank_size;
+            }
+        }
+        if (!size_left) {
+            /* No need to use the remaining banks. */
+            break;
+        }
+    }
+
+    ram_size -= size_left;
+    if (size_left) {
+        printf("Truncating memory to %d MiB to fit SDRAM controller limits.\n",
+               (int)(ram_size >> 20));
+    }
+
+    memory_region_allocate_system_memory(ram, NULL, "ppc4xx.sdram", ram_size);
+
+    size_left = ram_size;
+    for (i = 0; i < nr_banks && size_left; i++) {
+        for (j = 0; sdram_bank_sizes[j] != 0; j++) {
+            bank_size = sdram_bank_sizes[j];
+
+            if (bank_size <= size_left) {
+                char name[32];
+                snprintf(name, sizeof(name), "ppc4xx.sdram%d", i);
+                memory_region_init_alias(&ram_memories[i], NULL, name, ram,
+                                         base, bank_size);
+                ram_bases[i] = base;
+                ram_sizes[i] = bank_size;
+                base += bank_size;
+                size_left -= bank_size;
+                break;
+            }
+        }
+    }
+
+    return ram_size;
+}