Re: [Qemu-devel] [PATCH v1 4/7] STM32F2xx: Add the SPI device

[Alistair Francis]

On Sun, Apr 26, 2015 at 4:43 AM, Peter Crosthwaite
<address@hidden> wrote:
> On Sat, Apr 25, 2015 at 1:18 AM, Alistair Francis <address@hidden> wrote:
>> Add the STM32F2xx SPI device.
>>
>> Signed-off-by: Alistair Francis <address@hidden>
>> ---
>>
>>  default-configs/arm-softmmu.mak |   1 +
>>  hw/ssi/Makefile.objs            |   1 +
>>  hw/ssi/stm32f2xx_spi.c          | 211 
>> ++++++++++++++++++++++++++++++++++++++++
>>  include/hw/ssi/stm32f2xx_spi.h  |  74 ++++++++++++++
>>  4 files changed, 287 insertions(+)
>>  create mode 100644 hw/ssi/stm32f2xx_spi.c
>>  create mode 100644 include/hw/ssi/stm32f2xx_spi.h
>>
>> diff --git a/default-configs/arm-softmmu.mak 
>> b/default-configs/arm-softmmu.mak
>> index 2b16590..580fac3 100644
>> --- a/default-configs/arm-softmmu.mak
>> +++ b/default-configs/arm-softmmu.mak
>> @@ -85,6 +85,7 @@ CONFIG_STM32F2XX_TIMER=y
>>  CONFIG_STM32F2XX_USART=y
>>  CONFIG_STM32F2XX_SYSCFG=y
>>  CONFIG_STM32F2XX_ADC=y
>> +CONFIG_STM32F2XX_SPI=y
>>  CONFIG_STM32F205_SOC=y
>>
>>  CONFIG_VERSATILE_PCI=y
>> diff --git a/hw/ssi/Makefile.objs b/hw/ssi/Makefile.objs
>> index 9555825..c674247 100644
>> --- a/hw/ssi/Makefile.objs
>> +++ b/hw/ssi/Makefile.objs
>> @@ -2,5 +2,6 @@ common-obj-$(CONFIG_PL022) += pl022.o
>>  common-obj-$(CONFIG_SSI) += ssi.o
>>  common-obj-$(CONFIG_XILINX_SPI) += xilinx_spi.o
>>  common-obj-$(CONFIG_XILINX_SPIPS) += xilinx_spips.o
>> +common-obj-$(CONFIG_STM32F2XX_SPI) += stm32f2xx_spi.o
>>
>>  obj-$(CONFIG_OMAP) += omap_spi.o
>> diff --git a/hw/ssi/stm32f2xx_spi.c b/hw/ssi/stm32f2xx_spi.c
>> new file mode 100644
>> index 0000000..11bbdef
>> --- /dev/null
>> +++ b/hw/ssi/stm32f2xx_spi.c
>> @@ -0,0 +1,211 @@
>> +/*
>> + * STM32F405 SPI
>> + *
>> + * Copyright (c) 2014 Alistair Francis <address@hidden>
>> + *
>> + * 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/ssi/stm32f2xx_spi.h"
>> +
>> +#ifndef STM_SPI_ERR_DEBUG
>> +#define STM_SPI_ERR_DEBUG 0
>> +#endif
>> +
>> +#define DB_PRINT_L(lvl, fmt, args...) do { \
>> +    if (STM_SPI_ERR_DEBUG >= lvl) { \
>> +        qemu_log("%s: " fmt, __func__, ## args); \
>> +    } \
>> +} while (0);
>> +
>> +#define DB_PRINT(fmt, args...) DB_PRINT_L(1, fmt, ## args)
>> +
>> +static void stm32f2xx_spi_reset(DeviceState *dev)
>> +{
>> +    STM32F2XXSpiState *s = STM32F2XX_SPI(dev);
>> +
>> +    s->spi_cr1 = 0x00000000;
>> +    s->spi_cr2 = 0x00000000;
>> +    s->spi_sr = 0x0000000A;
>> +    s->spi_dr = 0x0000000C;
>> +    s->spi_crcpr = 0x00000007;
>> +    s->spi_rxcrcr = 0x00000000;
>> +    s->spi_txcrcr = 0x00000000;
>> +    s->spi_i2scfgr = 0x00000000;
>> +    s->spi_i2spr = 0x00000002;
>> +}
>> +
>> +static void stm32f2xx_spi_transfer(STM32F2XXSpiState *s)
>> +{
>> +    DB_PRINT("Data to send: 0x%x\n", s->spi_dr);
>> +
>> +    s->spi_dr = ssi_transfer(s->ssi, s->spi_dr);
>> +    s->spi_sr |= STM_SPI_SR_RXNE;
>> +
>> +    DB_PRINT("Data recieved: 0x%x\n", s->spi_dr);
>
> "received". I usually just us "tx" and "rx" in the strings though.

Good catch. I prefer using the full string as it explicitly describes what
is going on. Plus it's not that long.

> Using a %s __func__ you could probably dropthe sentance altogether.

The %s __func__ is included in the DB_PRINT() macro. Although as mentioned
I still like including the string, especially to indicate the direction.

>
>> +}
>> +
>> +static uint64_t stm32f2xx_spi_read(void *opaque, hwaddr addr,
>> +                                     unsigned int size)
>> +{
>> +    STM32F2XXSpiState *s = opaque;
>> +    uint32_t retval;
>> +
>> +    DB_PRINT("Read 0x%"HWADDR_PRIx"\n", addr);
>
> __func__
>
> Makes it sef contained and also consistent with ADC (and other devs).

Ok, I'll make it the same as the ADC, which is actually a little different
to some of the others :\

>
>> +
>> +    switch (addr) {
>> +    case STM_SPI_CR1:
>> +        return s->spi_cr1;
>> +    case STM_SPI_CR2:
>> +        qemu_log_mask(LOG_UNIMP, "%s: Interrupts and DMA are not 
>> implemented\n",
>> +                      __func__);
>> +        return s->spi_cr2;
>> +    case STM_SPI_SR:
>> +        retval = s->spi_sr;
>> +        return retval;
>> +    case STM_SPI_DR:
>> +        s->spi_sr |= STM_SPI_SR_BSY;
>> +        stm32f2xx_spi_transfer(s);
>
> This seems unusual to trigger the actual SPI transfer using the read
> txn. This would mean that this would be a very long bus transaction as
> you need to wait for the actual SPI byte txrx to happen during a
> single MMIO read. This can be very slow. Does the transfer occur on
> the write instead?

>From the data sheet it looks like the SPI transfer occurs on both reads/writes,
as there is only one register.

>From the data sheet:
"Data received or to be transmitted.
The data register is split into 2 buffers - one for writing (Transmit
Buffer) and another one for
reading (Receive buffer). A write to the data register will write into
the Tx buffer and a read
from the data register will return the value held in the Rx buffer."

>
>> +        s->spi_sr &= ~STM_SPI_SR_RXNE;
>> +        s->spi_sr &= ~STM_SPI_SR_BSY;
>
> This (and the |= of same above) should be unneeded as it will never be
> visible to the guest.

True, will remove.

>
>> +        return s->spi_dr;
>> +    case STM_SPI_CRCPR:
>> +        qemu_log_mask(LOG_UNIMP, "%s: CRC is not implemented, the registers 
>> " \
>> +                      "are includded for compatability\n", __func__);
>
> "included"

Good catch, will fix them all.

>
>> +        return s->spi_crcpr;
>> +    case STM_SPI_RXCRCR:
>> +        qemu_log_mask(LOG_UNIMP, "%s: CRC is not implemented, the registers 
>> " \
>> +                      "are includded for compatability\n", __func__);
>> +        return s->spi_rxcrcr;
>> +    case STM_SPI_TXCRCR:
>> +        qemu_log_mask(LOG_UNIMP, "%s: CRC is not implemented, the registers 
>> " \
>> +                      "are includded for compatability\n", __func__);
>
> You could perhaps factor out a lot of this string into a const
> variable to avoid the repetition.

That's true, but I don't think it's nesesary. It's only in the code a few times.

>
>> +        return s->spi_txcrcr;
>> +    case STM_SPI_I2SCFGR:
>> +        qemu_log_mask(LOG_UNIMP, "%s: I2S is not implemented, the registers 
>> " \
>> +                      "are includded for compatability\n", __func__);
>> +        return s->spi_i2scfgr;
>> +    case STM_SPI_I2SPR:
>> +        qemu_log_mask(LOG_UNIMP, "%s: I2S is not implemented, the registers 
>> " \
>> +                      "are includded for compatability\n", __func__);
>> +        return s->spi_i2spr;
>> +    default:
>> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n",
>> +                      __func__, addr);
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static void stm32f2xx_spi_write(void *opaque, hwaddr addr,
>> +                                uint64_t val64, unsigned int size)
>> +{
>> +    STM32F2XXSpiState *s = opaque;
>> +    uint32_t value = val64;
>> +
>> +    DB_PRINT("Write 0x%x at 0x%"HWADDR_PRIx"\n", value, addr);
>> +
>> +    switch (addr) {
>> +    case STM_SPI_CR1:
>> +        s->spi_cr1 = value;
>> +        return;
>> +    case STM_SPI_CR2:
>> +        qemu_log_mask(LOG_UNIMP, "%s: " \
>> +                      "Interrupts and DMA are not implemented\n", __func__);
>> +        s->spi_cr2 = value;
>> +        return;
>> +    case STM_SPI_SR:
>> +        /* Read only register, except for clearing the CRCERR bit, which
>> +         * is not supported
>> +         */
>> +        return;
>> +    case STM_SPI_DR:
>> +        s->spi_sr |= STM_SPI_SR_BSY;
>> +        s->spi_sr &= ~STM_SPI_SR_TXE;
>> +        s->spi_dr = value;
>> +        stm32f2xx_spi_transfer(s);
>
> So it does a transfer on the write as well. This means there are
> actually two transfers per write/read pair. One will be read only, the
> other write only. It is possible to do concurrent read and write with
> this IP?

>From what I get from the data sheet I don't think so. See the quote from
above.

>
>> +        s->spi_sr |= STM_SPI_SR_TXE;
>> +        s->spi_sr &= ~STM_SPI_SR_BSY;
>> +        return;
>> +    case STM_SPI_CRCPR:
>> +        qemu_log_mask(LOG_UNIMP, "%s: CRC is not implemented\n", __func__);
>> +        return;
>> +    case STM_SPI_RXCRCR:
>> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: Read only register: " \
>> +                      "0x%"HWADDR_PRIx"\n", __func__, addr);
>> +        return;
>> +    case STM_SPI_TXCRCR:
>> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: Read only register: " \
>> +                      "0x%"HWADDR_PRIx"\n", __func__, addr);
>> +        return;
>> +    case STM_SPI_I2SCFGR:
>> +        qemu_log_mask(LOG_UNIMP, "%s: " \
>> +                      "I2S is not implemented\n", __func__);
>> +        return;
>> +    case STM_SPI_I2SPR:
>> +        qemu_log_mask(LOG_UNIMP, "%s: " \
>> +                      "I2S is not implemented\n", __func__);
>> +        return;
>> +    default:
>> +        qemu_log_mask(LOG_GUEST_ERROR,
>> +                      "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
>> +    }
>> +}
>> +
>> +static const MemoryRegionOps stm32f2xx_spi_ops = {
>> +    .read = stm32f2xx_spi_read,
>> +    .write = stm32f2xx_spi_write,
>> +    .endianness = DEVICE_NATIVE_ENDIAN,
>> +};
>> +
>> +static void stm32f2xx_spi_init(Object *obj)
>> +{
>> +    STM32F2XXSpiState *s = STM32F2XX_SPI(obj);
>> +    DeviceState *dev = DEVICE(obj);
>> +
>> +    memory_region_init_io(&s->mmio, obj, &stm32f2xx_spi_ops, s,
>> +                          TYPE_STM32F2XX_SPI, 0x400);
>> +    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
>> +
>> +    sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);
>> +
>> +    s->ssi = ssi_create_bus(dev, "ssi");
>> +}
>> +
>> +static void stm32f2xx_spi_class_init(ObjectClass *klass, void *data)
>> +{
>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>> +
>> +    dc->reset = stm32f2xx_spi_reset;
>> +}
>> +
>> +static const TypeInfo stm32f2xx_spi_info = {
>> +    .name          = TYPE_STM32F2XX_SPI,
>> +    .parent        = TYPE_SYS_BUS_DEVICE,
>> +    .instance_size = sizeof(STM32F2XXSpiState),
>> +    .instance_init = stm32f2xx_spi_init,
>> +    .class_init    = stm32f2xx_spi_class_init,
>> +};
>> +
>> +static void stm32f2xx_spi_register_types(void)
>> +{
>> +    type_register_static(&stm32f2xx_spi_info);
>> +}
>> +
>> +type_init(stm32f2xx_spi_register_types)
>> diff --git a/include/hw/ssi/stm32f2xx_spi.h b/include/hw/ssi/stm32f2xx_spi.h
>> new file mode 100644
>> index 0000000..75dd6a8
>> --- /dev/null
>> +++ b/include/hw/ssi/stm32f2xx_spi.h
>> @@ -0,0 +1,74 @@
>> +/*
>> + * STM32F2XX SPI
>> + *
>> + * Copyright (c) 2014 Alistair Francis <address@hidden>
>> + *
>> + * 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.
>> + */
>> +
>> +#ifndef HW_STM32F2XX_SPI_H
>> +#define HW_STM32F2XX_SPI_H
>> +
>> +#include "hw/sysbus.h"
>> +#include "hw/hw.h"
>> +#include "hw/ssi.h"
>> +
>> +#define STM_SPI_CR1     0x00
>> +#define STM_SPI_CR2     0x04
>> +#define STM_SPI_SR      0x08
>> +#define STM_SPI_DR      0x0C
>> +#define STM_SPI_CRCPR   0x10
>> +#define STM_SPI_RXCRCR  0x14
>> +#define STM_SPI_TXCRCR  0x18
>> +#define STM_SPI_I2SCFGR 0x1C
>> +#define STM_SPI_I2SPR   0x20
>> +
>> +#define STM_SPI_CR1_SPE  (1 << 6)
>> +#define STM_SPI_CR1_MSTR (1 << 2)
>> +
>> +#define STM_SPI_SR_BSY   (1 << 7)
>> +#define STM_SPI_SR_TXE   (1 << 1)
>> +#define STM_SPI_SR_RXNE   1
>> +
>> +#define TYPE_STM32F2XX_SPI "stm32f2xx-spi"
>> +#define STM32F2XX_SPI(obj) \
>> +    OBJECT_CHECK(STM32F2XXSpiState, (obj), TYPE_STM32F2XX_SPI)
>> +
>> +typedef struct {
>> +    /* <private> */
>> +    SysBusDevice parent_obj;
>> +
>> +    /* <public> */
>> +    MemoryRegion mmio;
>> +
>> +    uint32_t spi_cr1;
>> +    uint32_t spi_cr2;
>> +    uint32_t spi_sr;
>> +    uint32_t spi_dr;
>> +    uint32_t spi_crcpr;
>> +    uint32_t spi_rxcrcr;
>> +    uint32_t spi_txcrcr;
>> +    uint32_t spi_i2scfgr;
>> +    uint32_t spi_i2spr;
>> +
>> +    qemu_irq irq;
>> +    SSIBus *ssi;
>> +} STM32F2XXSpiState;
>
> STM32F2XXSPIState

Ok, will fix.

Thanks,

Alistair

>
> Regards,
> Peter
>
>> +
>> +#endif /* HW_STM32F2XX_SPI_H */
>> --
>> 2.1.4
>>
>>