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-rw-r--r--hw/arm/Kconfig1
-rw-r--r--hw/arm/npcm7xx.c58
-rw-r--r--hw/ssi/meson.build1
-rw-r--r--hw/ssi/npcm7xx_fiu.c572
-rw-r--r--hw/ssi/trace-events11
-rw-r--r--include/hw/arm/npcm7xx.h2
-rw-r--r--include/hw/ssi/npcm7xx_fiu.h73
7 files changed, 718 insertions, 0 deletions
diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
index cd74642034..f303c6bead 100644
--- a/hw/arm/Kconfig
+++ b/hw/arm/Kconfig
@@ -361,6 +361,7 @@ config NPCM7XX
     select ARM_GIC
     select PL310  # cache controller
     select SERIAL
+    select SSI
     select UNIMP
 
 config FSL_IMX25
diff --git a/hw/arm/npcm7xx.c b/hw/arm/npcm7xx.c
index 6bb1693833..7884b2b03d 100644
--- a/hw/arm/npcm7xx.c
+++ b/hw/arm/npcm7xx.c
@@ -99,6 +99,39 @@ static const hwaddr npcm7xx_uart_addr[] = {
     0xf0004000,
 };
 
+/* Direct memory-mapped access to SPI0 CS0-1. */
+static const hwaddr npcm7xx_fiu0_flash_addr[] = {
+    0x80000000, /* CS0 */
+    0x88000000, /* CS1 */
+};
+
+/* Direct memory-mapped access to SPI3 CS0-3. */
+static const hwaddr npcm7xx_fiu3_flash_addr[] = {
+    0xa0000000, /* CS0 */
+    0xa8000000, /* CS1 */
+    0xb0000000, /* CS2 */
+    0xb8000000, /* CS3 */
+};
+
+static const struct {
+    const char *name;
+    hwaddr regs_addr;
+    int cs_count;
+    const hwaddr *flash_addr;
+} npcm7xx_fiu[] = {
+    {
+        .name = "fiu0",
+        .regs_addr = 0xfb000000,
+        .cs_count = ARRAY_SIZE(npcm7xx_fiu0_flash_addr),
+        .flash_addr = npcm7xx_fiu0_flash_addr,
+    }, {
+        .name = "fiu3",
+        .regs_addr = 0xc0000000,
+        .cs_count = ARRAY_SIZE(npcm7xx_fiu3_flash_addr),
+        .flash_addr = npcm7xx_fiu3_flash_addr,
+    },
+};
+
 static void npcm7xx_write_secondary_boot(ARMCPU *cpu,
                                          const struct arm_boot_info *info)
 {
@@ -192,6 +225,12 @@ static void npcm7xx_init(Object *obj)
     for (i = 0; i < ARRAY_SIZE(s->tim); i++) {
         object_initialize_child(obj, "tim[*]", &s->tim[i], TYPE_NPCM7XX_TIMER);
     }
+
+    QEMU_BUILD_BUG_ON(ARRAY_SIZE(npcm7xx_fiu) != ARRAY_SIZE(s->fiu));
+    for (i = 0; i < ARRAY_SIZE(s->fiu); i++) {
+        object_initialize_child(obj, npcm7xx_fiu[i].name, &s->fiu[i],
+                                TYPE_NPCM7XX_FIU);
+    }
 }
 
 static void npcm7xx_realize(DeviceState *dev, Error **errp)
@@ -291,6 +330,25 @@ static void npcm7xx_realize(DeviceState *dev, Error **errp)
                        serial_hd(i), DEVICE_LITTLE_ENDIAN);
     }
 
+    /*
+     * Flash Interface Unit (FIU). Can fail if incorrect number of chip selects
+     * specified, but this is a programming error.
+     */
+    QEMU_BUILD_BUG_ON(ARRAY_SIZE(npcm7xx_fiu) != ARRAY_SIZE(s->fiu));
+    for (i = 0; i < ARRAY_SIZE(s->fiu); i++) {
+        SysBusDevice *sbd = SYS_BUS_DEVICE(&s->fiu[i]);
+        int j;
+
+        object_property_set_int(OBJECT(sbd), "cs-count",
+                                npcm7xx_fiu[i].cs_count, &error_abort);
+        sysbus_realize(sbd, &error_abort);
+
+        sysbus_mmio_map(sbd, 0, npcm7xx_fiu[i].regs_addr);
+        for (j = 0; j < npcm7xx_fiu[i].cs_count; j++) {
+            sysbus_mmio_map(sbd, j + 1, npcm7xx_fiu[i].flash_addr[j]);
+        }
+    }
+
     /* RAM2 (SRAM) */
     memory_region_init_ram(&s->sram, OBJECT(dev), "ram2",
                            NPCM7XX_RAM2_SZ, &error_abort);
diff --git a/hw/ssi/meson.build b/hw/ssi/meson.build
index f1f5c287d0..dee00c0da6 100644
--- a/hw/ssi/meson.build
+++ b/hw/ssi/meson.build
@@ -1,5 +1,6 @@
 softmmu_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('aspeed_smc.c'))
 softmmu_ss.add(when: 'CONFIG_MSF2', if_true: files('mss-spi.c'))
+softmmu_ss.add(when: 'CONFIG_NPCM7XX', if_true: files('npcm7xx_fiu.c'))
 softmmu_ss.add(when: 'CONFIG_PL022', if_true: files('pl022.c'))
 softmmu_ss.add(when: 'CONFIG_SSI', if_true: files('ssi.c'))
 softmmu_ss.add(when: 'CONFIG_STM32F2XX_SPI', if_true: files('stm32f2xx_spi.c'))
diff --git a/hw/ssi/npcm7xx_fiu.c b/hw/ssi/npcm7xx_fiu.c
new file mode 100644
index 0000000000..104e8f2b96
--- /dev/null
+++ b/hw/ssi/npcm7xx_fiu.c
@@ -0,0 +1,572 @@
+/*
+ * Nuvoton NPCM7xx Flash Interface Unit (FIU)
+ *
+ * Copyright 2020 Google LLC
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+#include "qemu/osdep.h"
+
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "hw/ssi/npcm7xx_fiu.h"
+#include "migration/vmstate.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "qemu/units.h"
+
+#include "trace.h"
+
+/* Up to 128 MiB of flash may be accessed directly as memory. */
+#define NPCM7XX_FIU_FLASH_WINDOW_SIZE (128 * MiB)
+
+/* Each module has 4 KiB of register space. Only a fraction of it is used. */
+#define NPCM7XX_FIU_CTRL_REGS_SIZE (4 * KiB)
+
+/* 32-bit FIU register indices. */
+enum NPCM7xxFIURegister {
+    NPCM7XX_FIU_DRD_CFG,
+    NPCM7XX_FIU_DWR_CFG,
+    NPCM7XX_FIU_UMA_CFG,
+    NPCM7XX_FIU_UMA_CTS,
+    NPCM7XX_FIU_UMA_CMD,
+    NPCM7XX_FIU_UMA_ADDR,
+    NPCM7XX_FIU_PRT_CFG,
+    NPCM7XX_FIU_UMA_DW0 = 0x0020 / sizeof(uint32_t),
+    NPCM7XX_FIU_UMA_DW1,
+    NPCM7XX_FIU_UMA_DW2,
+    NPCM7XX_FIU_UMA_DW3,
+    NPCM7XX_FIU_UMA_DR0,
+    NPCM7XX_FIU_UMA_DR1,
+    NPCM7XX_FIU_UMA_DR2,
+    NPCM7XX_FIU_UMA_DR3,
+    NPCM7XX_FIU_PRT_CMD0,
+    NPCM7XX_FIU_PRT_CMD1,
+    NPCM7XX_FIU_PRT_CMD2,
+    NPCM7XX_FIU_PRT_CMD3,
+    NPCM7XX_FIU_PRT_CMD4,
+    NPCM7XX_FIU_PRT_CMD5,
+    NPCM7XX_FIU_PRT_CMD6,
+    NPCM7XX_FIU_PRT_CMD7,
+    NPCM7XX_FIU_PRT_CMD8,
+    NPCM7XX_FIU_PRT_CMD9,
+    NPCM7XX_FIU_CFG = 0x78 / sizeof(uint32_t),
+    NPCM7XX_FIU_REGS_END,
+};
+
+/* FIU_{DRD,DWR,UMA,PTR}_CFG cannot be written when this bit is set. */
+#define NPCM7XX_FIU_CFG_LCK BIT(31)
+
+/* Direct Read configuration register fields. */
+#define FIU_DRD_CFG_ADDSIZ(rv) extract32(rv, 16, 2)
+#define FIU_ADDSIZ_3BYTES 0
+#define FIU_ADDSIZ_4BYTES 1
+#define FIU_DRD_CFG_DBW(rv) extract32(rv, 12, 2)
+#define FIU_DRD_CFG_ACCTYPE(rv) extract32(rv, 8, 2)
+#define FIU_DRD_CFG_RDCMD(rv) extract32(rv, 0, 8)
+
+/* Direct Write configuration register fields. */
+#define FIU_DWR_CFG_ADDSIZ(rv) extract32(rv, 16, 2)
+#define FIU_DWR_CFG_WRCMD(rv) extract32(rv, 0, 8)
+
+/* User-Mode Access register fields. */
+
+/* Command Mode Lock and the bits protected by it. */
+#define FIU_UMA_CFG_CMMLCK BIT(30)
+#define FIU_UMA_CFG_CMMLCK_MASK 0x00000403
+
+#define FIU_UMA_CFG_RDATSIZ(rv) extract32(rv, 24, 5)
+#define FIU_UMA_CFG_DBSIZ(rv) extract32(rv, 21, 3)
+#define FIU_UMA_CFG_WDATSIZ(rv) extract32(rv, 16, 5)
+#define FIU_UMA_CFG_ADDSIZ(rv) extract32(rv, 11, 3)
+#define FIU_UMA_CFG_CMDSIZ(rv) extract32(rv, 10, 1)
+#define FIU_UMA_CFG_DBPCK(rv) extract32(rv, 6, 2)
+
+#define FIU_UMA_CTS_RDYIE BIT(25)
+#define FIU_UMA_CTS_RDYST BIT(24)
+#define FIU_UMA_CTS_SW_CS BIT(16)
+#define FIU_UMA_CTS_DEV_NUM(rv) extract32(rv, 8, 2)
+#define FIU_UMA_CTS_EXEC_DONE BIT(0)
+
+/*
+ * Returns the index of flash in the fiu->flash array. This corresponds to the
+ * chip select ID of the flash.
+ */
+static int npcm7xx_fiu_cs_index(NPCM7xxFIUState *fiu, NPCM7xxFIUFlash *flash)
+{
+    int index = flash - fiu->flash;
+
+    g_assert(index >= 0 && index < fiu->cs_count);
+
+    return index;
+}
+
+/* Assert the chip select specified in the UMA Control/Status Register. */
+static void npcm7xx_fiu_select(NPCM7xxFIUState *s, int cs_id)
+{
+    trace_npcm7xx_fiu_select(DEVICE(s)->canonical_path, cs_id);
+
+    if (cs_id < s->cs_count) {
+        qemu_irq_lower(s->cs_lines[cs_id]);
+    } else {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: UMA to CS%d; this module has only %d chip selects",
+                      DEVICE(s)->canonical_path, cs_id, s->cs_count);
+        cs_id = -1;
+    }
+
+    s->active_cs = cs_id;
+}
+
+/* Deassert the currently active chip select. */
+static void npcm7xx_fiu_deselect(NPCM7xxFIUState *s)
+{
+    if (s->active_cs < 0) {
+        return;
+    }
+
+    trace_npcm7xx_fiu_deselect(DEVICE(s)->canonical_path, s->active_cs);
+
+    qemu_irq_raise(s->cs_lines[s->active_cs]);
+    s->active_cs = -1;
+}
+
+/* Direct flash memory read handler. */
+static uint64_t npcm7xx_fiu_flash_read(void *opaque, hwaddr addr,
+                                       unsigned int size)
+{
+    NPCM7xxFIUFlash *f = opaque;
+    NPCM7xxFIUState *fiu = f->fiu;
+    uint64_t value = 0;
+    uint32_t drd_cfg;
+    int dummy_cycles;
+    int i;
+
+    if (fiu->active_cs != -1) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: direct flash read with CS%d already active",
+                      DEVICE(fiu)->canonical_path, fiu->active_cs);
+    }
+
+    npcm7xx_fiu_select(fiu, npcm7xx_fiu_cs_index(fiu, f));
+
+    drd_cfg = fiu->regs[NPCM7XX_FIU_DRD_CFG];
+    ssi_transfer(fiu->spi, FIU_DRD_CFG_RDCMD(drd_cfg));
+
+    switch (FIU_DRD_CFG_ADDSIZ(drd_cfg)) {
+    case FIU_ADDSIZ_4BYTES:
+        ssi_transfer(fiu->spi, extract32(addr, 24, 8));
+        /* fall through */
+    case FIU_ADDSIZ_3BYTES:
+        ssi_transfer(fiu->spi, extract32(addr, 16, 8));
+        ssi_transfer(fiu->spi, extract32(addr, 8, 8));
+        ssi_transfer(fiu->spi, extract32(addr, 0, 8));
+        break;
+
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: bad address size %d\n",
+                      DEVICE(fiu)->canonical_path, FIU_DRD_CFG_ADDSIZ(drd_cfg));
+        break;
+    }
+
+    /* Flash chip model expects one transfer per dummy bit, not byte */
+    dummy_cycles =
+        (FIU_DRD_CFG_DBW(drd_cfg) * 8) >> FIU_DRD_CFG_ACCTYPE(drd_cfg);
+    for (i = 0; i < dummy_cycles; i++) {
+        ssi_transfer(fiu->spi, 0);
+    }
+
+    for (i = 0; i < size; i++) {
+        value = deposit64(value, 8 * i, 8, ssi_transfer(fiu->spi, 0));
+    }
+
+    trace_npcm7xx_fiu_flash_read(DEVICE(fiu)->canonical_path, fiu->active_cs,
+                                 addr, size, value);
+
+    npcm7xx_fiu_deselect(fiu);
+
+    return value;
+}
+
+/* Direct flash memory write handler. */
+static void npcm7xx_fiu_flash_write(void *opaque, hwaddr addr, uint64_t v,
+                                    unsigned int size)
+{
+    NPCM7xxFIUFlash *f = opaque;
+    NPCM7xxFIUState *fiu = f->fiu;
+    uint32_t dwr_cfg;
+    int cs_id;
+    int i;
+
+    if (fiu->active_cs != -1) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: direct flash write with CS%d already active",
+                      DEVICE(fiu)->canonical_path, fiu->active_cs);
+    }
+
+    cs_id = npcm7xx_fiu_cs_index(fiu, f);
+    trace_npcm7xx_fiu_flash_write(DEVICE(fiu)->canonical_path, cs_id, addr,
+                                  size, v);
+    npcm7xx_fiu_select(fiu, cs_id);
+
+    dwr_cfg = fiu->regs[NPCM7XX_FIU_DWR_CFG];
+    ssi_transfer(fiu->spi, FIU_DWR_CFG_WRCMD(dwr_cfg));
+
+    switch (FIU_DWR_CFG_ADDSIZ(dwr_cfg)) {
+    case FIU_ADDSIZ_4BYTES:
+        ssi_transfer(fiu->spi, extract32(addr, 24, 8));
+        /* fall through */
+    case FIU_ADDSIZ_3BYTES:
+        ssi_transfer(fiu->spi, extract32(addr, 16, 8));
+        ssi_transfer(fiu->spi, extract32(addr, 8, 8));
+        ssi_transfer(fiu->spi, extract32(addr, 0, 8));
+        break;
+
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: bad address size %d\n",
+                      DEVICE(fiu)->canonical_path, FIU_DWR_CFG_ADDSIZ(dwr_cfg));
+        break;
+    }
+
+    for (i = 0; i < size; i++) {
+        ssi_transfer(fiu->spi, extract64(v, i * 8, 8));
+    }
+
+    npcm7xx_fiu_deselect(fiu);
+}
+
+static const MemoryRegionOps npcm7xx_fiu_flash_ops = {
+    .read = npcm7xx_fiu_flash_read,
+    .write = npcm7xx_fiu_flash_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 8,
+        .unaligned = true,
+    },
+};
+
+/* Control register read handler. */
+static uint64_t npcm7xx_fiu_ctrl_read(void *opaque, hwaddr addr,
+                                      unsigned int size)
+{
+    hwaddr reg = addr / sizeof(uint32_t);
+    NPCM7xxFIUState *s = opaque;
+    uint32_t value;
+
+    if (reg < NPCM7XX_FIU_NR_REGS) {
+        value = s->regs[reg];
+    } else {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: read from invalid offset 0x%" PRIx64 "\n",
+                      DEVICE(s)->canonical_path, addr);
+        value = 0;
+    }
+
+    trace_npcm7xx_fiu_ctrl_read(DEVICE(s)->canonical_path, addr, value);
+
+    return value;
+}
+
+/* Send the specified number of address bytes from the UMA address register. */
+static void send_address(SSIBus *spi, unsigned int addsiz, uint32_t addr)
+{
+    switch (addsiz) {
+    case 4:
+        ssi_transfer(spi, extract32(addr, 24, 8));
+        /* fall through */
+    case 3:
+        ssi_transfer(spi, extract32(addr, 16, 8));
+        /* fall through */
+    case 2:
+        ssi_transfer(spi, extract32(addr, 8, 8));
+        /* fall through */
+    case 1:
+        ssi_transfer(spi, extract32(addr, 0, 8));
+        /* fall through */
+    case 0:
+        break;
+    }
+}
+
+/* Send the number of dummy bits specified in the UMA config register. */
+static void send_dummy_bits(SSIBus *spi, uint32_t uma_cfg, uint32_t uma_cmd)
+{
+    unsigned int bits_per_clock = 1U << FIU_UMA_CFG_DBPCK(uma_cfg);
+    unsigned int i;
+
+    for (i = 0; i < FIU_UMA_CFG_DBSIZ(uma_cfg); i++) {
+        /* Use bytes 0 and 1 first, then keep repeating byte 2 */
+        unsigned int field = (i < 2) ? ((i + 1) * 8) : 24;
+        unsigned int j;
+
+        for (j = 0; j < 8; j += bits_per_clock) {
+            ssi_transfer(spi, extract32(uma_cmd, field + j, bits_per_clock));
+        }
+    }
+}
+
+/* Perform a User-Mode Access transaction. */
+static void npcm7xx_fiu_uma_transaction(NPCM7xxFIUState *s)
+{
+    uint32_t uma_cts = s->regs[NPCM7XX_FIU_UMA_CTS];
+    uint32_t uma_cfg;
+    unsigned int i;
+
+    /* SW_CS means the CS is already forced low, so don't touch it. */
+    if (uma_cts & FIU_UMA_CTS_SW_CS) {
+        int cs_id = FIU_UMA_CTS_DEV_NUM(s->regs[NPCM7XX_FIU_UMA_CTS]);
+        npcm7xx_fiu_select(s, cs_id);
+    }
+
+    /* Send command, if present. */
+    uma_cfg = s->regs[NPCM7XX_FIU_UMA_CFG];
+    if (FIU_UMA_CFG_CMDSIZ(uma_cfg) > 0) {
+        ssi_transfer(s->spi, extract32(s->regs[NPCM7XX_FIU_UMA_CMD], 0, 8));
+    }
+
+    /* Send address, if present. */
+    send_address(s->spi, FIU_UMA_CFG_ADDSIZ(uma_cfg),
+                 s->regs[NPCM7XX_FIU_UMA_ADDR]);
+
+    /* Write data, if present. */
+    for (i = 0; i < FIU_UMA_CFG_WDATSIZ(uma_cfg); i++) {
+        unsigned int reg =
+            (i < 16) ? (NPCM7XX_FIU_UMA_DW0 + i / 4) : NPCM7XX_FIU_UMA_DW3;
+        unsigned int field = (i % 4) * 8;
+
+        ssi_transfer(s->spi, extract32(s->regs[reg], field, 8));
+    }
+
+    /* Send dummy bits, if present. */
+    send_dummy_bits(s->spi, uma_cfg, s->regs[NPCM7XX_FIU_UMA_CMD]);
+
+    /* Read data, if present. */
+    for (i = 0; i < FIU_UMA_CFG_RDATSIZ(uma_cfg); i++) {
+        unsigned int reg = NPCM7XX_FIU_UMA_DR0 + i / 4;
+        unsigned int field = (i % 4) * 8;
+        uint8_t c;
+
+        c = ssi_transfer(s->spi, 0);
+        if (reg <= NPCM7XX_FIU_UMA_DR3) {
+            s->regs[reg] = deposit32(s->regs[reg], field, 8, c);
+        }
+    }
+
+    /* Again, don't touch CS if the user is forcing it low. */
+    if (uma_cts & FIU_UMA_CTS_SW_CS) {
+        npcm7xx_fiu_deselect(s);
+    }
+
+    /* RDYST means a command has completed since it was cleared. */
+    s->regs[NPCM7XX_FIU_UMA_CTS] |= FIU_UMA_CTS_RDYST;
+    /* EXEC_DONE means Execute Command / Not Done, so clear it here. */
+    s->regs[NPCM7XX_FIU_UMA_CTS] &= ~FIU_UMA_CTS_EXEC_DONE;
+}
+
+/* Control register write handler. */
+static void npcm7xx_fiu_ctrl_write(void *opaque, hwaddr addr, uint64_t v,
+                                   unsigned int size)
+{
+    hwaddr reg = addr / sizeof(uint32_t);
+    NPCM7xxFIUState *s = opaque;
+    uint32_t value = v;
+
+    trace_npcm7xx_fiu_ctrl_write(DEVICE(s)->canonical_path, addr, value);
+
+    switch (reg) {
+    case NPCM7XX_FIU_UMA_CFG:
+        if (s->regs[reg] & FIU_UMA_CFG_CMMLCK) {
+            value &= ~FIU_UMA_CFG_CMMLCK_MASK;
+            value |= (s->regs[reg] & FIU_UMA_CFG_CMMLCK_MASK);
+        }
+        /* fall through */
+    case NPCM7XX_FIU_DRD_CFG:
+    case NPCM7XX_FIU_DWR_CFG:
+        if (s->regs[reg] & NPCM7XX_FIU_CFG_LCK) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: write to locked register @ 0x%" PRIx64 "\n",
+                          DEVICE(s)->canonical_path, addr);
+            return;
+        }
+        s->regs[reg] = value;
+        break;
+
+    case NPCM7XX_FIU_UMA_CTS:
+        if (value & FIU_UMA_CTS_RDYST) {
+            value &= ~FIU_UMA_CTS_RDYST;
+        } else {
+            value |= s->regs[reg] & FIU_UMA_CTS_RDYST;
+        }
+        if ((s->regs[reg] ^ value) & FIU_UMA_CTS_SW_CS) {
+            if (value & FIU_UMA_CTS_SW_CS) {
+                /*
+                 * Don't drop CS if there's a transfer in progress, or we're
+                 * about to start one.
+                 */
+                if (!((value | s->regs[reg]) & FIU_UMA_CTS_EXEC_DONE)) {
+                    npcm7xx_fiu_deselect(s);
+                }
+            } else {
+                int cs_id = FIU_UMA_CTS_DEV_NUM(s->regs[NPCM7XX_FIU_UMA_CTS]);
+                npcm7xx_fiu_select(s, cs_id);
+            }
+        }
+        s->regs[reg] = value | (s->regs[reg] & FIU_UMA_CTS_EXEC_DONE);
+        if (value & FIU_UMA_CTS_EXEC_DONE) {
+            npcm7xx_fiu_uma_transaction(s);
+        }
+        break;
+
+    case NPCM7XX_FIU_UMA_DR0 ... NPCM7XX_FIU_UMA_DR3:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: write to read-only register @ 0x%" PRIx64 "\n",
+                      DEVICE(s)->canonical_path, addr);
+        return;
+
+    case NPCM7XX_FIU_PRT_CFG:
+    case NPCM7XX_FIU_PRT_CMD0 ... NPCM7XX_FIU_PRT_CMD9:
+        qemu_log_mask(LOG_UNIMP, "%s: PRT is not implemented\n", __func__);
+        break;
+
+    case NPCM7XX_FIU_UMA_CMD:
+    case NPCM7XX_FIU_UMA_ADDR:
+    case NPCM7XX_FIU_UMA_DW0 ... NPCM7XX_FIU_UMA_DW3:
+    case NPCM7XX_FIU_CFG:
+        s->regs[reg] = value;
+        break;
+
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: write to invalid offset 0x%" PRIx64 "\n",
+                      DEVICE(s)->canonical_path, addr);
+        return;
+    }
+}
+
+static const MemoryRegionOps npcm7xx_fiu_ctrl_ops = {
+    .read = npcm7xx_fiu_ctrl_read,
+    .write = npcm7xx_fiu_ctrl_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+        .unaligned = false,
+    },
+};
+
+static void npcm7xx_fiu_enter_reset(Object *obj, ResetType type)
+{
+    NPCM7xxFIUState *s = NPCM7XX_FIU(obj);
+
+    trace_npcm7xx_fiu_enter_reset(DEVICE(obj)->canonical_path, type);
+
+    memset(s->regs, 0, sizeof(s->regs));
+
+    s->regs[NPCM7XX_FIU_DRD_CFG] = 0x0300100b;
+    s->regs[NPCM7XX_FIU_DWR_CFG] = 0x03000002;
+    s->regs[NPCM7XX_FIU_UMA_CFG] = 0x00000400;
+    s->regs[NPCM7XX_FIU_UMA_CTS] = 0x00010000;
+    s->regs[NPCM7XX_FIU_UMA_CMD] = 0x0000000b;
+    s->regs[NPCM7XX_FIU_PRT_CFG] = 0x00000400;
+    s->regs[NPCM7XX_FIU_CFG] = 0x0000000b;
+}
+
+static void npcm7xx_fiu_hold_reset(Object *obj)
+{
+    NPCM7xxFIUState *s = NPCM7XX_FIU(obj);
+    int i;
+
+    trace_npcm7xx_fiu_hold_reset(DEVICE(obj)->canonical_path);
+
+    for (i = 0; i < s->cs_count; i++) {
+        qemu_irq_raise(s->cs_lines[i]);
+    }
+}
+
+static void npcm7xx_fiu_realize(DeviceState *dev, Error **errp)
+{
+    NPCM7xxFIUState *s = NPCM7XX_FIU(dev);
+    SysBusDevice *sbd = &s->parent;
+    int i;
+
+    if (s->cs_count <= 0) {
+        error_setg(errp, "%s: %d chip selects specified, need at least one",
+                   dev->canonical_path, s->cs_count);
+        return;
+    }
+
+    s->spi = ssi_create_bus(dev, "spi");
+    s->cs_lines = g_new0(qemu_irq, s->cs_count);
+    qdev_init_gpio_out_named(DEVICE(s), s->cs_lines, "cs", s->cs_count);
+    s->flash = g_new0(NPCM7xxFIUFlash, s->cs_count);
+
+    /*
+     * Register the control registers region first. It may be followed by one
+     * or more direct flash access regions.
+     */
+    memory_region_init_io(&s->mmio, OBJECT(s), &npcm7xx_fiu_ctrl_ops, s, "ctrl",
+                          NPCM7XX_FIU_CTRL_REGS_SIZE);
+    sysbus_init_mmio(sbd, &s->mmio);
+
+    for (i = 0; i < s->cs_count; i++) {
+        NPCM7xxFIUFlash *flash = &s->flash[i];
+        flash->fiu = s;
+        memory_region_init_io(&flash->direct_access, OBJECT(s),
+                              &npcm7xx_fiu_flash_ops, &s->flash[i], "flash",
+                              NPCM7XX_FIU_FLASH_WINDOW_SIZE);
+        sysbus_init_mmio(sbd, &flash->direct_access);
+    }
+}
+
+static const VMStateDescription vmstate_npcm7xx_fiu = {
+    .name = "npcm7xx-fiu",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT32(active_cs, NPCM7xxFIUState),
+        VMSTATE_UINT32_ARRAY(regs, NPCM7xxFIUState, NPCM7XX_FIU_NR_REGS),
+        VMSTATE_END_OF_LIST(),
+    },
+};
+
+static Property npcm7xx_fiu_properties[] = {
+    DEFINE_PROP_INT32("cs-count", NPCM7xxFIUState, cs_count, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void npcm7xx_fiu_class_init(ObjectClass *klass, void *data)
+{
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    QEMU_BUILD_BUG_ON(NPCM7XX_FIU_REGS_END > NPCM7XX_FIU_NR_REGS);
+
+    dc->desc = "NPCM7xx Flash Interface Unit";
+    dc->realize = npcm7xx_fiu_realize;
+    dc->vmsd = &vmstate_npcm7xx_fiu;
+    rc->phases.enter = npcm7xx_fiu_enter_reset;
+    rc->phases.hold = npcm7xx_fiu_hold_reset;
+    device_class_set_props(dc, npcm7xx_fiu_properties);
+}
+
+static const TypeInfo npcm7xx_fiu_types[] = {
+    {
+        .name = TYPE_NPCM7XX_FIU,
+        .parent = TYPE_SYS_BUS_DEVICE,
+        .instance_size = sizeof(NPCM7xxFIUState),
+        .class_init = npcm7xx_fiu_class_init,
+    },
+};
+DEFINE_TYPES(npcm7xx_fiu_types);
diff --git a/hw/ssi/trace-events b/hw/ssi/trace-events
index 0ea498de91..2f83ef833f 100644
--- a/hw/ssi/trace-events
+++ b/hw/ssi/trace-events
@@ -9,3 +9,14 @@ aspeed_smc_dma_checksum(uint32_t addr, uint32_t data) "0x%08x: 0x%08x"
 aspeed_smc_dma_rw(const char *dir, uint32_t flash_addr, uint32_t dram_addr, uint32_t size) "%s flash:@0x%08x dram:@0x%08x size:0x%08x"
 aspeed_smc_write(uint64_t addr,  uint32_t size, uint64_t data) "@0x%" PRIx64 " size %u: 0x%" PRIx64
 aspeed_smc_flash_select(int cs, const char *prefix) "CS%d %sselect"
+
+# npcm7xx_fiu.c
+
+npcm7xx_fiu_enter_reset(const char *id, int reset_type) "%s reset type: %d"
+npcm7xx_fiu_hold_reset(const char *id) "%s"
+npcm7xx_fiu_select(const char *id, int cs) "%s select CS%d"
+npcm7xx_fiu_deselect(const char *id, int cs) "%s deselect CS%d"
+npcm7xx_fiu_ctrl_read(const char *id, uint64_t addr, uint32_t data) "%s offset: 0x%04" PRIx64 " value: 0x%08" PRIx32
+npcm7xx_fiu_ctrl_write(const char *id, uint64_t addr, uint32_t data) "%s offset: 0x%04" PRIx64 " value: 0x%08" PRIx32
+npcm7xx_fiu_flash_read(const char *id, int cs, uint64_t addr, unsigned int size, uint64_t value) "%s[%d] offset: 0x%08" PRIx64 " size: %u value: 0x%" PRIx64
+npcm7xx_fiu_flash_write(const char *id, int cs, uint64_t addr, unsigned int size, uint64_t value) "%s[%d] offset: 0x%08" PRIx64 " size: %u value: 0x%" PRIx64
diff --git a/include/hw/arm/npcm7xx.h b/include/hw/arm/npcm7xx.h
index 9fa84a0702..78d0d78c52 100644
--- a/include/hw/arm/npcm7xx.h
+++ b/include/hw/arm/npcm7xx.h
@@ -23,6 +23,7 @@
 #include "hw/misc/npcm7xx_gcr.h"
 #include "hw/nvram/npcm7xx_otp.h"
 #include "hw/timer/npcm7xx_timer.h"
+#include "hw/ssi/npcm7xx_fiu.h"
 #include "target/arm/cpu.h"
 
 #define NPCM7XX_MAX_NUM_CPUS    (2)
@@ -73,6 +74,7 @@ typedef struct NPCM7xxState {
     NPCM7xxOTPState     key_storage;
     NPCM7xxOTPState     fuse_array;
     NPCM7xxMCState      mc;
+    NPCM7xxFIUState     fiu[2];
 } NPCM7xxState;
 
 #define TYPE_NPCM7XX    "npcm7xx"
diff --git a/include/hw/ssi/npcm7xx_fiu.h b/include/hw/ssi/npcm7xx_fiu.h
new file mode 100644
index 0000000000..a3a1704289
--- /dev/null
+++ b/include/hw/ssi/npcm7xx_fiu.h
@@ -0,0 +1,73 @@
+/*
+ * Nuvoton NPCM7xx Flash Interface Unit (FIU)
+ *
+ * Copyright 2020 Google LLC
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+#ifndef NPCM7XX_FIU_H
+#define NPCM7XX_FIU_H
+
+#include "hw/ssi/ssi.h"
+#include "hw/sysbus.h"
+
+/*
+ * Number of registers in our device state structure. Don't change this without
+ * incrementing the version_id in the vmstate.
+ */
+#define NPCM7XX_FIU_NR_REGS (0x7c / sizeof(uint32_t))
+
+typedef struct NPCM7xxFIUState NPCM7xxFIUState;
+
+/**
+ * struct NPCM7xxFIUFlash - Per-chipselect flash controller state.
+ * @direct_access: Memory region for direct flash access.
+ * @fiu: Pointer to flash controller shared state.
+ */
+typedef struct NPCM7xxFIUFlash {
+    MemoryRegion direct_access;
+    NPCM7xxFIUState *fiu;
+} NPCM7xxFIUFlash;
+
+/**
+ * NPCM7xxFIUState - Device state for one Flash Interface Unit.
+ * @parent: System bus device.
+ * @mmio: Memory region for register access.
+ * @cs_count: Number of flash chips that may be connected to this module.
+ * @active_cs: Currently active chip select, or -1 if no chip is selected.
+ * @cs_lines: GPIO lines that may be wired to flash chips.
+ * @flash: Array of @cs_count per-flash-chip state objects.
+ * @spi: The SPI bus mastered by this controller.
+ * @regs: Register contents.
+ *
+ * Each FIU has a shared bank of registers, and controls up to four chip
+ * selects. Each chip select has a dedicated memory region which may be used to
+ * read and write the flash connected to that chip select as if it were memory.
+ */
+struct NPCM7xxFIUState {
+    SysBusDevice parent;
+
+    MemoryRegion mmio;
+
+    int32_t cs_count;
+    int32_t active_cs;
+    qemu_irq *cs_lines;
+    NPCM7xxFIUFlash *flash;
+
+    SSIBus *spi;
+
+    uint32_t regs[NPCM7XX_FIU_NR_REGS];
+};
+
+#define TYPE_NPCM7XX_FIU "npcm7xx-fiu"
+#define NPCM7XX_FIU(obj) OBJECT_CHECK(NPCM7xxFIUState, (obj), TYPE_NPCM7XX_FIU)
+
+#endif /* NPCM7XX_FIU_H */