Re: [Qemu-devel] [PATCH] hw/misc: Add support for ADC controller in Xilinx Zynq 7000

["Edgar E. Iglesias" <edgar.iglesias@xilinx.com>]

On Wed, Aug 12, 2015 at 02:33:47PM -0700, Guenter Roeck wrote:
> Add support for the Xilinx XADC core used in Zynq 7000.
> 
> References:
> - Zynq-7000 All Programmable SoC Technical Reference Manual
> - 7 Series FPGAs and Zynq-7000 All Programmable SoC XADC
>   Dual 12-Bit 1 MSPS Analog-to-Digital Converter
> 
> Tested with Linux using qemu machine xilinx-zynq-a9 with devicetree
> files zynq-zc702.dtb and zynq-zc706.dtb, and kernel configuration
> multi_v7_defconfig.


Adding Alistair to CC.
A few comments inline.


> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>  hw/arm/xilinx_zynq.c  |   5 +
>  hw/misc/Makefile.objs |   1 +
>  hw/misc/zynq_xadc.c   | 305 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 311 insertions(+)
>  create mode 100644 hw/misc/zynq_xadc.c
> 
> diff --git a/hw/arm/xilinx_zynq.c b/hw/arm/xilinx_zynq.c
> index a4e7b5c..195e9f1 100644
> --- a/hw/arm/xilinx_zynq.c
> +++ b/hw/arm/xilinx_zynq.c
> @@ -225,6 +225,11 @@ static void zynq_init(MachineState *machine)
>      sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, 0xE0101000);
>      sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, pic[79-IRQ_OFFSET]);
>  
> +    dev = qdev_create(NULL, "xilinx,zynq_xadc");
> +    qdev_init_nofail(dev);
> +    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, 0xF8007100);
> +    sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, pic[39-IRQ_OFFSET]);
> +
>      dev = qdev_create(NULL, "pl330");
>      qdev_prop_set_uint8(dev, "num_chnls",  8);
>      qdev_prop_set_uint8(dev, "num_periph_req",  4);
> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
> index 4aa76ff..5f76f05 100644
> --- a/hw/misc/Makefile.objs
> +++ b/hw/misc/Makefile.objs
> @@ -36,6 +36,7 @@ obj-$(CONFIG_OMAP) += omap_sdrc.o
>  obj-$(CONFIG_OMAP) += omap_tap.o
>  obj-$(CONFIG_SLAVIO) += slavio_misc.o
>  obj-$(CONFIG_ZYNQ) += zynq_slcr.o
> +obj-$(CONFIG_ZYNQ) += zynq_xadc.o
>  obj-$(CONFIG_STM32F2XX_SYSCFG) += stm32f2xx_syscfg.o
>  
>  obj-$(CONFIG_PVPANIC) += pvpanic.o
> diff --git a/hw/misc/zynq_xadc.c b/hw/misc/zynq_xadc.c
> new file mode 100644
> index 0000000..480e2bf
> --- /dev/null
> +++ b/hw/misc/zynq_xadc.c
> @@ -0,0 +1,305 @@
> +/*
> + * ADC registers for Xilinx Zynq Platform
> + *
> + * Copyright (c) 2015 Guenter Roeck
> + * Based on hw/misc/zynq_slcr.c, written by Michal Simek
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "hw/hw.h"
> +#include "qemu/timer.h"
> +#include "hw/sysbus.h"
> +#include "sysemu/sysemu.h"
> +
> +enum {
> +    CFG                = 0x000 / 4,
> +    INTSTS,
> +    INTMSK,
> +    STATUS,
> +    CFIFO,
> +    DFIFO,
> +    CTL,
> +};
> +
> +#define XADC_ZYNQ_CFG_ENABLE            BIT(31)
> +#define XADC_ZYNQ_CFG_CFIFOTH_RD(x)     (((x) >> 20) & 0x0f)
> +#define XADC_ZYNQ_CFG_DFIFOTH_RD(x)     (((x) >> 16) & 0x0f)
> +#define XADC_ZYNQ_CFG_WEDGE             BIT(13)
> +#define XADC_ZYNQ_CFG_REDGE             BIT(12)
> +#define XADC_ZYNQ_CFG_TCKRATE_DIV2      (0x0 << 8)
> +#define XADC_ZYNQ_CFG_TCKRATE_DIV4      (0x1 << 8)
> +#define XADC_ZYNQ_CFG_TCKRATE_DIV8      (0x2 << 8)
> +#define XADC_ZYNQ_CFG_TCKRATE_DIV16     (0x3 << 8)
> +#define XADC_ZYNQ_CFG_IGAP_MASK         0x1f
> +#define XADC_ZYNQ_CFG_IGAP(x)           ((x) & XADC_ZYNQ_CFG_IGAP_MASK)
> +
> +#define XADC_ZYNQ_INT_CFIFO_LTH         BIT(9)
> +#define XADC_ZYNQ_INT_DFIFO_GTH         BIT(8)
> +#define XADC_ZYNQ_INT_ALARM_MASK        0xff
> +#define XADC_ZYNQ_INT_ALARM_OFFSET      0
> +
> +#define XADC_ZYNQ_STATUS_DFIFO_LVL(x)   (((x) & 0x0f) << 12)
> +#define XADC_ZYNQ_STATUS_CFIFOF         BIT(11)
> +#define XADC_ZYNQ_STATUS_CFIFOE         BIT(10)
> +#define XADC_ZYNQ_STATUS_DFIFOF         BIT(9)
> +#define XADC_ZYNQ_STATUS_DFIFOE         BIT(8)
> +#define XADC_ZYNQ_STATUS_OT             BIT(7)
> +#define XADC_ZYNQ_STATUS_ALM(x)         BIT(x)
> +
> +#define XADC_ZYNQ_CTL_RESET             BIT(4)
> +
> +#define XADC_ZYNQ_CMD_NOP               0x00
> +#define XADC_ZYNQ_CMD_READ              0x01
> +#define XADC_ZYNQ_CMD_WRITE             0x02
> +
> +#define ZYNQ_XADC_MMIO_SIZE     0x0020
> +#define ZYNQ_XADC_NUM_IO_REGS   (ZYNQ_XADC_MMIO_SIZE / 4)
> +#define ZYNQ_XADC_NUM_ADC_REGS  128
> +#define ZYNQ_XADC_FIFO_DEPTH    15
> +
> +#define TYPE_ZYNQ_XADC          "xilinx,zynq_xadc"
> +#define ZYNQ_XADC(obj) \
> +    OBJECT_CHECK(ZynqXADCState, (obj), TYPE_ZYNQ_XADC)
> +
> +typedef struct ZynqXADCState {
> +    SysBusDevice parent_obj;
> +
> +    MemoryRegion iomem;
> +
> +    uint32_t regs[ZYNQ_XADC_NUM_IO_REGS];       /* I/O registers */
> +    uint16_t xadc_regs[ZYNQ_XADC_NUM_ADC_REGS]; /* XADC registers */
> +    uint16_t xadc_read_reg_previous;    /* result of most recent read command */
> +    uint16_t xadc_dfifo[ZYNQ_XADC_FIFO_DEPTH];  /* data fifo */
> +    uint16_t xadc_dfifo_depth;                  /* entries in data fifo */
> +
> +    struct IRQState *irq;
> +
> +} ZynqXADCState;
> +
> +static void _zynq_xadc_reset(ZynqXADCState *s)
> +{
> +    int i;
> +
> +    s->regs[CFG] = XADC_ZYNQ_CFG_IGAP(0x14) | XADC_ZYNQ_CFG_TCKRATE_DIV4 |
> +        XADC_ZYNQ_CFG_REDGE;
> +    s->regs[INTSTS] = XADC_ZYNQ_INT_CFIFO_LTH;
> +    s->regs[INTMSK] = 0xffffffff;
> +    s->regs[STATUS] = 0;
> +    s->regs[CFIFO] = 0;
> +    s->regs[DFIFO] = 0;
> +    s->regs[CTL] = XADC_ZYNQ_CTL_RESET;
> +
> +    for (i = 0; i < ARRAY_SIZE(s->xadc_regs); i++) {
> +        s->xadc_regs[i] = 0;
> +    }
> +    for (i = 0; i < ARRAY_SIZE(s->xadc_dfifo); i++) {
> +        s->xadc_dfifo[i] = 0;
> +    }
> +    s->xadc_dfifo_depth = 0;
> +}
> +
> +static void zynq_xadc_reset(DeviceState *d)
> +{
> +    _zynq_xadc_reset(ZYNQ_XADC(d));

Historically we've tried to avoid symbolnames starting with _.
You could rename or maybe stick to one reset func?



> +}
> +
> +static bool zynq_xadc_check_offset(hwaddr offset, bool rnw)
> +{
> +    switch (offset) {
> +    case CFG:
> +    case INTMSK:
> +    case INTSTS:
> +    case CTL:
> +        return true;
> +    case DFIFO:
> +    case STATUS:
> +        return rnw;     /* read only */
> +    case CFIFO:
> +        return !rnw;    /* Write only */
> +    default:
> +        return false;
> +    }
> +}
> +
> +static void zynq_xadc_update_ints(ZynqXADCState *s)
> +{
> +    qemu_set_irq(s->irq, !!(s->regs[INTSTS] & ~s->regs[INTMSK]));
> +}
> +
> +static uint64_t zynq_xadc_read(void *opaque, hwaddr offset, unsigned size)
> +{
> +    ZynqXADCState *s = opaque;
> +    int reg = offset / 4;
> +    uint64_t rv = 0;
> +    int i;
> +
> +    if (!zynq_xadc_check_offset(reg, true)) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "zynq_xadc: Invalid read access to "
> +                      " addr %" HWADDR_PRIx "\n", offset);
> +    }
> +
> +    switch (reg) {
> +    case CFG:
> +    case INTMSK:
> +    case INTSTS:
> +    case CTL:
> +        rv = s->regs[reg];
> +        break;
> +    case STATUS:
> +        rv = XADC_ZYNQ_STATUS_CFIFOE;
> +        rv |= XADC_ZYNQ_STATUS_DFIFO_LVL(s->xadc_dfifo_depth);
> +        if (!s->xadc_dfifo_depth) {
> +            rv |= XADC_ZYNQ_STATUS_DFIFOE;
> +        } else if (s->xadc_dfifo_depth >= ARRAY_SIZE(s->xadc_dfifo)) {
> +            rv |= XADC_ZYNQ_STATUS_DFIFOF;
> +        }
> +        break;
> +    case DFIFO:
> +        rv = s->xadc_dfifo[0];
> +        if (s->xadc_dfifo_depth > 0) {
> +            s->xadc_dfifo_depth--;
> +        }
> +        for (i = 0; i < s->xadc_dfifo_depth; i++) {
> +            s->xadc_dfifo[i] = s->xadc_dfifo[i + 1];
> +        }
> +        s->xadc_dfifo[s->xadc_dfifo_depth] = 0;
> +        zynq_xadc_update_ints(s);
> +        break;
> +    }
> +    return rv;
> +}
> +
> +static void xadc_add_dfifo(ZynqXADCState *s, uint16_t regval)
> +{
> +    if (s->xadc_dfifo_depth < ARRAY_SIZE(s->xadc_dfifo)) {
> +            s->xadc_dfifo[s->xadc_dfifo_depth++] = s->xadc_read_reg_previous;
> +    }
> +    s->xadc_read_reg_previous = regval;
> +    if (s->xadc_dfifo_depth > XADC_ZYNQ_CFG_DFIFOTH_RD(s->regs[CFG])) {
> +        s->regs[INTSTS] |= XADC_ZYNQ_INT_DFIFO_GTH;
> +    }
> +    zynq_xadc_update_ints(s);
> +}
> +
> +static void zynq_xadc_write(void *opaque, hwaddr offset, uint64_t val,
> +                            unsigned size)
> +{
> +    ZynqXADCState *s = (ZynqXADCState *)opaque;
> +    int reg = offset / 4;
> +    int xadc_reg;
> +    int xadc_cmd;
> +    int xadc_data;
> +
> +    if (!zynq_xadc_check_offset(reg, false)) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "zynq_xadc: Invalid write access to "
> +                      "addr %" HWADDR_PRIx "\n", offset);
> +        return;
> +    }
> +
> +    switch (reg) {
> +    case CFG:
> +        s->regs[CFG] = val;
> +        break;
> +    case INTSTS:
> +        s->regs[INTSTS] &= ~val;
> +        zynq_xadc_update_ints(s);
> +        break;
> +    case INTMSK:
> +        s->regs[INTMSK] = val & 0x003ff;
> +        zynq_xadc_update_ints(s);
> +        break;
> +    case CFIFO:
> +        xadc_reg = (val >> 16) & 0x007f;
> +        xadc_cmd = (val >> 26) & 0x0f;
> +        xadc_data = val & 0xffff;

We have extract* functions to make these field extractions a bit more
readable. For example see extract32 in include/qemu/bitops.h.


> +
> +        switch (xadc_cmd) {
> +        case XADC_ZYNQ_CMD_READ:
> +            xadc_add_dfifo(s, s->xadc_regs[xadc_reg]);
> +            break;
> +        case XADC_ZYNQ_CMD_WRITE:
> +            s->xadc_regs[xadc_reg] = xadc_data;
> +            break;
> +        case XADC_ZYNQ_CMD_NOP:
> +            xadc_add_dfifo(s, 0);
> +            break;
> +        }
> +        s->regs[INTSTS] |= XADC_ZYNQ_INT_CFIFO_LTH;
> +        zynq_xadc_update_ints(s);
> +        break;
> +    case CTL:
> +        if (val & XADC_ZYNQ_CTL_RESET) {
> +            _zynq_xadc_reset(s);
> +        }
> +        s->regs[CTL] = val & 0x00fffeff;
> +        break;
> +    }
> +}
> +
> +static const MemoryRegionOps xadc_ops = {
> +    .read = zynq_xadc_read,
> +    .write = zynq_xadc_write,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +};
> +
> +static void zynq_xadc_init(Object *obj)
> +{
> +    ZynqXADCState *s = ZYNQ_XADC(obj);
> +
> +    memory_region_init_io(&s->iomem, obj, &xadc_ops, s, "xadc",
> +                          ZYNQ_XADC_MMIO_SIZE);
> +    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->iomem);
> +}
> +
> +static const VMStateDescription vmstate_zynq_xadc = {
> +    .name = "zynq_xadc",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_UINT32_ARRAY(regs, ZynqXADCState, ZYNQ_XADC_NUM_IO_REGS),
> +        VMSTATE_UINT16_ARRAY(xadc_regs, ZynqXADCState, ZYNQ_XADC_NUM_ADC_REGS),
> +        VMSTATE_UINT16_ARRAY(xadc_dfifo, ZynqXADCState, ZYNQ_XADC_FIFO_DEPTH),
> +        VMSTATE_UINT16(xadc_read_reg_previous, ZynqXADCState),
> +        VMSTATE_UINT16(xadc_dfifo_depth, ZynqXADCState),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +static void zynq_xadc_realize(DeviceState *d, Error ** errp)
> +{
> +    SysBusDevice *sbd = SYS_BUS_DEVICE(d);
> +    ZynqXADCState *s = ZYNQ_XADC(d);
> +
> +    sysbus_init_irq(sbd, &s->irq);
> +}
> +
> +static void zynq_xadc_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->vmsd = &vmstate_zynq_xadc;
> +    dc->reset = zynq_xadc_reset;
> +    dc->realize = zynq_xadc_realize;
> +}
> +
> +static const TypeInfo zynq_xadc_info = {
> +    .class_init = zynq_xadc_class_init,
> +    .name  = TYPE_ZYNQ_XADC,
> +    .parent = TYPE_SYS_BUS_DEVICE,
> +    .instance_size  = sizeof(ZynqXADCState),
> +    .instance_init = zynq_xadc_init,
> +};
> +
> +static void zynq_xadc_register_types(void)
> +{
> +    type_register_static(&zynq_xadc_info);
> +}
> +
> +type_init(zynq_xadc_register_types)
> -- 
> 2.1.4
>