hw/riscv: sifive_u: Add QSPI0 controller and connect a flash

This adds the QSPI0 controller to the SoC, and connects an ISSI
25WP256 flash to it. The generation of corresponding device tree
source fragment is also added.

Since the direct memory-mapped mode is not supported by the SiFive
SPI model, the <reg> property does not populate the second group
which represents the memory mapped address of the SPI flash.

With this commit, upstream U-Boot for the SiFive HiFive Unleashed
board can boot on QEMU 'sifive_u' out of the box. This allows users
to develop and test the recommended RISC-V boot flow with a real
world use case: ZSBL (in QEMU) loads U-Boot SPL from SPI flash to
L2LIM, then U-Boot SPL loads the payload from SPI flash that is
combined with OpenSBI fw_dynamic firmware and U-Boot proper.

Specify machine property `msel` to 6 to allow booting from the SPI
flash. U-Boot spl is directly loaded via `-bios`, and subsequent
payload is stored in the SPI flash image. Example command line:

$ qemu-system-riscv64 -nographic -M sifive_u,msel=6 -smp 5 -m 8G \
    -bios u-boot-spl.bin -drive file=spi-nor.img,if=mtd

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20210126060007.12904-5-bmeng.cn@gmail.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

2 files changed, 54 insertions, 0 deletions

diff --git a/hw/riscv/Kconfig b/hw/riscv/Kconfig
index facb0cb..6330297 100644
--- a/hw/riscv/Kconfig
+++ b/hw/riscv/Kconfig
@@ -52,9 +52,11 @@ config SIFIVE_U
     select SIFIVE_GPIO
     select SIFIVE_PDMA
     select SIFIVE_PLIC
+    select SIFIVE_SPI
     select SIFIVE_UART
     select SIFIVE_U_OTP
     select SIFIVE_U_PRCI
+    select SSI_M25P80
     select UNIMP
 
 config SPIKE
diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
index 59b61ce..43a0e98 100644
--- a/hw/riscv/sifive_u.c
+++ b/hw/riscv/sifive_u.c
@@ -15,6 +15,7 @@
  * 5) OTP (One-Time Programmable) memory with stored serial number
  * 6) GEM (Gigabit Ethernet Controller) and management block
  * 7) DMA (Direct Memory Access Controller)
+ * 8) SPI0 connected to an SPI flash
  *
  * This board currently generates devicetree dynamically that indicates at least
  * two harts and up to five harts.
@@ -44,6 +45,7 @@
 #include "hw/char/serial.h"
 #include "hw/cpu/cluster.h"
 #include "hw/misc/unimp.h"
+#include "hw/ssi/ssi.h"
 #include "target/riscv/cpu.h"
 #include "hw/riscv/riscv_hart.h"
 #include "hw/riscv/sifive_u.h"
@@ -74,6 +76,7 @@ static const struct MemmapEntry {
     [SIFIVE_U_DEV_PRCI] =     { 0x10000000,     0x1000 },
     [SIFIVE_U_DEV_UART0] =    { 0x10010000,     0x1000 },
     [SIFIVE_U_DEV_UART1] =    { 0x10011000,     0x1000 },
+    [SIFIVE_U_DEV_QSPI0] =    { 0x10040000,     0x1000 },
     [SIFIVE_U_DEV_GPIO] =     { 0x10060000,     0x1000 },
     [SIFIVE_U_DEV_OTP] =      { 0x10070000,     0x1000 },
     [SIFIVE_U_DEV_GEM] =      { 0x10090000,     0x2000 },
@@ -342,6 +345,32 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
                             "sifive,fu540-c000-ccache");
     g_free(nodename);
 
+    nodename = g_strdup_printf("/soc/spi@%lx",
+        (long)memmap[SIFIVE_U_DEV_QSPI0].base);
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_cell(fdt, nodename, "#size-cells", 0);
+    qemu_fdt_setprop_cell(fdt, nodename, "#address-cells", 1);
+    qemu_fdt_setprop_cells(fdt, nodename, "clocks",
+        prci_phandle, PRCI_CLK_TLCLK);
+    qemu_fdt_setprop_cell(fdt, nodename, "interrupts", SIFIVE_U_QSPI0_IRQ);
+    qemu_fdt_setprop_cell(fdt, nodename, "interrupt-parent", plic_phandle);
+    qemu_fdt_setprop_cells(fdt, nodename, "reg",
+        0x0, memmap[SIFIVE_U_DEV_QSPI0].base,
+        0x0, memmap[SIFIVE_U_DEV_QSPI0].size);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible", "sifive,spi0");
+    g_free(nodename);
+
+    nodename = g_strdup_printf("/soc/spi@%lx/flash@0",
+        (long)memmap[SIFIVE_U_DEV_QSPI0].base);
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_cell(fdt, nodename, "spi-rx-bus-width", 4);
+    qemu_fdt_setprop_cell(fdt, nodename, "spi-tx-bus-width", 4);
+    qemu_fdt_setprop(fdt, nodename, "m25p,fast-read", NULL, 0);
+    qemu_fdt_setprop_cell(fdt, nodename, "spi-max-frequency", 50000000);
+    qemu_fdt_setprop_cell(fdt, nodename, "reg", 0);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible", "jedec,spi-nor");
+    g_free(nodename);
+
     phy_phandle = phandle++;
     nodename = g_strdup_printf("/soc/ethernet@%lx",
         (long)memmap[SIFIVE_U_DEV_GEM].base);
@@ -439,6 +468,9 @@ static void sifive_u_machine_init(MachineState *machine)
     int i;
     uint32_t fdt_load_addr;
     uint64_t kernel_entry;
+    DriveInfo *dinfo;
+    DeviceState *flash_dev;
+    qemu_irq flash_cs;
 
     /* Initialize SoC */
     object_initialize_child(OBJECT(machine), "soc", &s->soc, TYPE_RISCV_U_SOC);
@@ -571,6 +603,19 @@ static void sifive_u_machine_init(MachineState *machine)
     riscv_rom_copy_firmware_info(machine, memmap[SIFIVE_U_DEV_MROM].base,
                                  memmap[SIFIVE_U_DEV_MROM].size,
                                  sizeof(reset_vec), kernel_entry);
+
+    /* Connect an SPI flash to SPI0 */
+    flash_dev = qdev_new("is25wp256");
+    dinfo = drive_get_next(IF_MTD);
+    if (dinfo) {
+        qdev_prop_set_drive_err(flash_dev, "drive",
+                                blk_by_legacy_dinfo(dinfo),
+                                &error_fatal);
+    }
+    qdev_realize_and_unref(flash_dev, BUS(s->soc.spi0.spi), &error_fatal);
+
+    flash_cs = qdev_get_gpio_in_named(flash_dev, SSI_GPIO_CS, 0);
+    sysbus_connect_irq(SYS_BUS_DEVICE(&s->soc.spi0), 1, flash_cs);
 }
 
 static bool sifive_u_machine_get_start_in_flash(Object *obj, Error **errp)
@@ -680,6 +725,7 @@ static void sifive_u_soc_instance_init(Object *obj)
     object_initialize_child(obj, "gem", &s->gem, TYPE_CADENCE_GEM);
     object_initialize_child(obj, "gpio", &s->gpio, TYPE_SIFIVE_GPIO);
     object_initialize_child(obj, "pdma", &s->dma, TYPE_SIFIVE_PDMA);
+    object_initialize_child(obj, "spi0", &s->spi0, TYPE_SIFIVE_SPI);
 }
 
 static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
@@ -827,6 +873,12 @@ static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
 
     create_unimplemented_device("riscv.sifive.u.l2cc",
         memmap[SIFIVE_U_DEV_L2CC].base, memmap[SIFIVE_U_DEV_L2CC].size);
+
+    sysbus_realize(SYS_BUS_DEVICE(&s->spi0), errp);
+    sysbus_mmio_map(SYS_BUS_DEVICE(&s->spi0), 0,
+                    memmap[SIFIVE_U_DEV_QSPI0].base);
+    sysbus_connect_irq(SYS_BUS_DEVICE(&s->spi0), 0,
+                       qdev_get_gpio_in(DEVICE(s->plic), SIFIVE_U_QSPI0_IRQ));
 }
 
 static Property sifive_u_soc_props[] = {