Re: [PATCH v2 4/5] spi: bcm-mspi: Make BCMA optional to support non-BCMA chips

[Jonathan Richardson <jonathar-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>]

Jonas, thanks for the review. Comments below.

On 15-04-08 12:27 PM, Jonas Gorski wrote:
> Hi,
> 
> On Wed, Apr 8, 2015 at 8:04 PM, Jonathan Richardson
> <jonathar-dY08KVG/lbpWk0Htik3J/w@public.gmane.org> wrote:
>> The Broadcom MSPI controller is used on various chips. The driver only
>> supported BCM53xx chips with BCMA (an AMBA bus variant). It now supports
>> both BCMA MSPI and non-BCMA MSPI. To do this the following changes were
>> made:
>>
>>   - A new config for non-BCMA chips has been added.
>>   - Common code between the BCMA and non BCMA version are shared.
>>   - Function pointers to set read/write functions to abstract bcma
>>     and non-bcma versions are provided.
>>   - DT is now mandatory. Hard coded SPI devices are removed and must be
>>     set in DT.
>>   - Remove function was unnecessary and removed.
>>
>> Signed-off-by: Jonathan Richardson <jonathar-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
>> ---
>>  drivers/spi/Kconfig        |    5 +
>>  drivers/spi/Makefile       |    1 +
>>  drivers/spi/spi-bcm-mspi.c |  228 ++++++++++++++++++++++++++++++++------------
>>  3 files changed, 171 insertions(+), 63 deletions(-)
>>
>> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
>> index 766e08d..23f2357 100644
>> --- a/drivers/spi/Kconfig
>> +++ b/drivers/spi/Kconfig
>> @@ -120,6 +120,11 @@ config SPI_BCMA_MSPI
>>         help
>>           Enable support for the Broadcom BCMA MSPI controller.
>>
>> +config SPI_BCM_MSPI
>> +       tristate "Broadcom MSPI controller"
> 
> You say "DT is now mandatory", but I don't see you depending on OF.
> Does it compile with OF disabled?
> 
>> +       help
>> +         Enable support for the Broadcom MSPI controller.
>> +
>>  config SPI_BCM63XX
>>         tristate "Broadcom BCM63xx SPI controller"
>>         depends on BCM63XX
>> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
>> index 6b58100..36872d2 100644
>> --- a/drivers/spi/Makefile
>> +++ b/drivers/spi/Makefile
>> @@ -16,6 +16,7 @@ obj-$(CONFIG_SPI_ATH79)                       += spi-ath79.o
>>  obj-$(CONFIG_SPI_AU1550)               += spi-au1550.o
>>  obj-$(CONFIG_SPI_BCM2835)              += spi-bcm2835.o
>>  obj-$(CONFIG_SPI_BCMA_MSPI)            += spi-bcm-mspi.o
>> +obj-$(CONFIG_SPI_BCM_MSPI)             += spi-bcm-mspi.o
> 
> What happens if SPI_BCMA_MSPI and SPI_BCM_MSPI are both set? What
> happens if they disagree, i.e. one is y, the other m?

If they're both set then everything compiles fine. But if y/m then you
don't get a module. Only if you set both to m will you get a module. I
could possibly force both to m in the makefile or split into 3 files.

Any preference or another idea?

> 
>>  obj-$(CONFIG_SPI_BCM63XX)              += spi-bcm63xx.o
>>  obj-$(CONFIG_SPI_BCM63XX_HSSPI)                += spi-bcm63xx-hsspi.o
>>  obj-$(CONFIG_SPI_BFIN5XX)              += spi-bfin5xx.o
>> diff --git a/drivers/spi/spi-bcm-mspi.c b/drivers/spi/spi-bcm-mspi.c
>> index 502227d..32bb1f0 100644
>> --- a/drivers/spi/spi-bcm-mspi.c
>> +++ b/drivers/spi/spi-bcm-mspi.c
>> @@ -11,11 +11,13 @@
>>   * GNU General Public License for more details.
>>   */
>>  #include <linux/kernel.h>
>> +#include <linux/platform_device.h>
>>  #include <linux/module.h>
>>  #include <linux/slab.h>
>>  #include <linux/delay.h>
>>  #include <linux/bcma/bcma.h>
>>  #include <linux/spi/spi.h>
>> +#include <linux/of.h>
>>
>>  #include "spi-bcm-mspi.h"
>>
>> @@ -25,22 +27,17 @@
>>  #define BCM_MSPI_SPE_TIMEOUT_MS 80
>>
>>  struct bcm_mspi {
>> +#ifdef CONFIG_SPI_BCMA_MSPI
>>         struct bcma_device *core;
>> -       struct spi_master *master;
>> +#endif
>>
>> +       void __iomem *base;
>> +       struct spi_master *master;
> 
> You could make this part a bit more readable by not reordering existing members.
> 
>>         size_t read_offset;
>> -};
>> -
>> -static inline u32 bcm_mspi_read(struct bcm_mspi *mspi, u16 offset)
>> -{
>> -       return bcma_read32(mspi->core, offset);
>> -}
>>
>> -static inline void bcm_mspi_write(struct bcm_mspi *mspi, u16 offset,
>> -                                   u32 value)
>> -{
>> -       bcma_write32(mspi->core, offset, value);
>> -}
>> +       void (*mspi_write)(struct bcm_mspi *mspi, u16 offset, u32 value);
>> +       u32 (*mspi_read)(struct bcm_mspi *mspi, u16 offset);
>> +};
> 
> Why not keep these and let them call mspi->mspi_read() resp.
> mspi->mspi_write()? It would reduce the amount of changes quite a bit.
> 
>>
>>  static inline unsigned int bcm_mspi_calc_timeout(size_t len)
>>  {
>> @@ -56,7 +53,7 @@ static int bcm_mspi_wait(struct bcm_mspi *mspi, unsigned int timeout_ms)
>>         /* SPE bit has to be 0 before we read MSPI STATUS */
>>         deadline = jiffies + BCM_MSPI_SPE_TIMEOUT_MS * HZ / 1000;
>>         do {
>> -               tmp = bcm_mspi_read(mspi, MSPI_SPCR2);
>> +               tmp = mspi->mspi_read(mspi, MSPI_SPCR2);
>>                 if (!(tmp & MSPI_SPCR2_SPE))
>>                         break;
>>                 udelay(5);
>> @@ -68,9 +65,9 @@ static int bcm_mspi_wait(struct bcm_mspi *mspi, unsigned int timeout_ms)
>>         /* Check status */
>>         deadline = jiffies + timeout_ms * HZ / 1000;
>>         do {
>> -               tmp = bcm_mspi_read(mspi, MSPI_STATUS);
>> +               tmp = mspi->mspi_read(mspi, MSPI_STATUS);
>>                 if (tmp & MSPI_STATUS_SPIF) {
>> -                       bcm_mspi_write(mspi, MSPI_STATUS, 0);
>> +                       mspi->mspi_write(mspi, MSPI_STATUS, 0);
>>                         return 0;
>>                 }
>>
>> @@ -79,7 +76,7 @@ static int bcm_mspi_wait(struct bcm_mspi *mspi, unsigned int timeout_ms)
>>         } while (!time_after_eq(jiffies, deadline));
>>
>>  spi_timeout:
>> -       bcm_mspi_write(mspi, MSPI_STATUS, 0);
>> +       mspi->mspi_write(mspi, MSPI_STATUS, 0);
>>
>>         pr_err("Timeout waiting for SPI to be ready!\n");
>>
>> @@ -94,7 +91,7 @@ static void bcm_mspi_buf_write(struct bcm_mspi *mspi, u8 *w_buf,
>>
>>         for (i = 0; i < len; i++) {
>>                 /* Transmit Register File MSB */
>> -               bcm_mspi_write(mspi, MSPI_TXRAM + 4 * (i * 2),
>> +               mspi->mspi_write(mspi, MSPI_TXRAM + 4 * (i * 2),
>>                                  (unsigned int)w_buf[i]);
>>         }
>>
>> @@ -105,28 +102,28 @@ static void bcm_mspi_buf_write(struct bcm_mspi *mspi, u8 *w_buf,
>>                         tmp &= ~MSPI_CDRAM_CONT;
>>                 tmp &= ~0x1;
>>                 /* Command Register File */
>> -               bcm_mspi_write(mspi, MSPI_CDRAM + 4 * i, tmp);
>> +               mspi->mspi_write(mspi, MSPI_CDRAM + 4 * i, tmp);
>>         }
>>
>>         /* Set queue pointers */
>> -       bcm_mspi_write(mspi, MSPI_NEWQP, 0);
>> -       bcm_mspi_write(mspi, MSPI_ENDQP, len - 1);
>> +       mspi->mspi_write(mspi, MSPI_NEWQP, 0);
>> +       mspi->mspi_write(mspi, MSPI_ENDQP, len - 1);
>>
>>         if (cont)
>> -               bcm_mspi_write(mspi, MSPI_WRITE_LOCK, 1);
>> +               mspi->mspi_write(mspi, MSPI_WRITE_LOCK, 1);
>>
>>         /* Start SPI transfer */
>> -       tmp = bcm_mspi_read(mspi, MSPI_SPCR2);
>> +       tmp = mspi->mspi_read(mspi, MSPI_SPCR2);
>>         tmp |= MSPI_SPCR2_SPE;
>>         if (cont)
>>                 tmp |= MSPI_SPCR2_CONT_AFTER_CMD;
>> -       bcm_mspi_write(mspi, MSPI_SPCR2, tmp);
>> +       mspi->mspi_write(mspi, MSPI_SPCR2, tmp);
>>
>>         /* Wait for SPI to finish */
>>         bcm_mspi_wait(mspi, bcm_mspi_calc_timeout(len));
>>
>>         if (!cont)
>> -               bcm_mspi_write(mspi, MSPI_WRITE_LOCK, 0);
>> +               mspi->mspi_write(mspi, MSPI_WRITE_LOCK, 0);
>>
>>         mspi->read_offset = len;
>>  }
>> @@ -144,34 +141,35 @@ static void bcm_mspi_buf_read(struct bcm_mspi *mspi, u8 *r_buf,
>>                         tmp &= ~MSPI_CDRAM_CONT;
>>                 tmp &= ~0x1;
>>                 /* Command Register File */
>> -               bcm_mspi_write(mspi, MSPI_CDRAM + 4 * i, tmp);
>> +               mspi->mspi_write(mspi, MSPI_CDRAM + 4 * i, tmp);
>>         }
>>
>>         /* Set queue pointers */
>> -       bcm_mspi_write(mspi, MSPI_NEWQP, 0);
>> -       bcm_mspi_write(mspi, MSPI_ENDQP, mspi->read_offset + len - 1);
>> +       mspi->mspi_write(mspi, MSPI_NEWQP, 0);
>> +       mspi->mspi_write(mspi, MSPI_ENDQP,
>> +                        mspi->read_offset + len - 1);
>>
>>         if (cont)
>> -               bcm_mspi_write(mspi, MSPI_WRITE_LOCK, 1);
>> +               mspi->mspi_write(mspi, MSPI_WRITE_LOCK, 1);
>>
>>         /* Start SPI transfer */
>> -       tmp = bcm_mspi_read(mspi, MSPI_SPCR2);
>> +       tmp = mspi->mspi_read(mspi, MSPI_SPCR2);
>>         tmp |= MSPI_SPCR2_SPE;
>>         if (cont)
>>                 tmp |= MSPI_SPCR2_CONT_AFTER_CMD;
>> -       bcm_mspi_write(mspi, MSPI_SPCR2, tmp);
>> +       mspi->mspi_write(mspi, MSPI_SPCR2, tmp);
>>
>>         /* Wait for SPI to finish */
>>         bcm_mspi_wait(mspi, bcm_mspi_calc_timeout(len));
>>
>>         if (!cont)
>> -               bcm_mspi_write(mspi, MSPI_WRITE_LOCK, 0);
>> +               mspi->mspi_write(mspi, MSPI_WRITE_LOCK, 0);
>>
>>         for (i = 0; i < len; ++i) {
>>                 int offset = mspi->read_offset + i;
>>
>>                 /* Data stored in the transmit register file LSB */
>> -               r_buf[i] = (u8)bcm_mspi_read(mspi,
>> +               r_buf[i] = (u8)mspi->mspi_read(mspi,
>>                         MSPI_RXRAM + 4 * (1 + offset * 2));
>>         }
>>
>> @@ -216,10 +214,104 @@ static int bcm_mspi_transfer_one(struct spi_master *master,
>>         return 0;
>>  }
>>
>> -static struct spi_board_info bcm_mspi_info = {
>> -       .modalias       = "bcm53xxspiflash",
>> +/*
>> + * Allocate SPI master for both bcma and non bcma bus. The SPI device must be
>> + * configured in DT.
>> + */
>> +static struct bcm_mspi *bcm_mspi_init(struct device *dev)
>> +{
>> +       struct bcm_mspi *data;
>> +       struct spi_master *master;
>> +
>> +       master = spi_alloc_master(dev, sizeof(*data));
>> +       if (!master) {
>> +               dev_err(dev, "error allocating spi_master\n");
>> +               return 0;
> 
> return NULL;
> 
>> +       }
>> +
>> +       data = spi_master_get_devdata(master);
>> +       data->master = master;
>> +
>> +       /* SPI master will always use the SPI device(s) from DT. */
>> +       master->dev.of_node = dev->of_node;
>> +       master->transfer_one = bcm_mspi_transfer_one;
>> +
>> +       return data;
>> +}
>> +
>> +#ifdef CONFIG_SPI_BCM_MSPI
> 
> Won't this break when being build as a module? I think you need
> 
> #if IS_ENABLED(CONFIG_SPI_BCM_MSPI)
> 
>> +
>> +static const struct of_device_id bcm_mspi_dt[] = {
>> +       { .compatible = "brcm,mspi" },
>> +       { },
>> +};
>> +MODULE_DEVICE_TABLE(of, bcm_mspi_dt);
>> +
>> +static inline u32 bcm_mspi_read(struct bcm_mspi *mspi, u16 offset)
>> +{
>> +       return readl(mspi->base + offset);
>> +}
>> +
>> +static inline void bcm_mspi_write(struct bcm_mspi *mspi, u16 offset,
>> +       u32 value)
>> +{
>> +       writel(value, mspi->base + offset);
>> +}
>> +
>> +/*
>> + * Probe routine for non-bcma devices.
>> + */
>> +static int bcm_mspi_probe(struct platform_device *pdev)
>> +{
>> +       struct bcm_mspi *data;
>> +       struct device *dev = &pdev->dev;
>> +       int err;
>> +       struct resource *res;
>> +
>> +       dev_info(dev, "BCM MSPI probe\n");
>> +
>> +       data = bcm_mspi_init(dev);
>> +       if (!data)
>> +               return -ENOMEM;
>> +
>> +       /* Map base memory address. */
>> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +       data->base = devm_ioremap_resource(dev, res);
>> +       if (IS_ERR(data->base)) {
>> +               dev_err(&pdev->dev, "unable to map I/O memory\n");
> 
> devm_ioremap_resource will already complain for you.
> 
>> +               err = PTR_ERR(data->base);
>> +               goto out;
>> +       }
>> +
>> +       data->mspi_read = bcm_mspi_read;
>> +       data->mspi_write = bcm_mspi_write;
>> +       platform_set_drvdata(pdev, data);
>> +
>> +       err = devm_spi_register_master(dev, data->master);
>> +       if (err)
>> +               goto out;
>> +
>> +       return 0;
>> +
>> +out:
>> +       spi_master_put(data->master);
>> +       return err;
>> +}
>> +
>> +static struct platform_driver bcm_mspi_driver = {
>> +       .driver = {
>> +               .name = "bcm-mspi",
>> +               .of_match_table = bcm_mspi_dt,
>> +       },
>> +       .probe = bcm_mspi_probe,
>>  };
>>
>> +module_platform_driver(bcm_mspi_driver);
>> +
>> +#endif
>> +
>> +#ifdef CONFIG_SPI_BCMA_MSPI
> 
> likewise.
> 
>> +
>>  static const struct bcma_device_id bcm_mspi_bcma_tbl[] = {
>>         BCMA_CORE(BCMA_MANUF_BCM, BCMA_CORE_NS_QSPI, BCMA_ANY_REV,
>>                 BCMA_ANY_CLASS),
>> @@ -227,62 +319,70 @@ static const struct bcma_device_id bcm_mspi_bcma_tbl[] = {
>>  };
>>  MODULE_DEVICE_TABLE(bcma, bcm_mspi_bcma_tbl);
>>
>> +static const struct of_device_id bcm_bcma_mspi_dt[] = {
>> +       { .compatible = "brcm,bcma-mspi" },
>> +       { },
>> +};
>> +MODULE_DEVICE_TABLE(of, bcm_mspi_dt);
>> +
>> +static inline u32 bcm_bcma_mspi_read(struct bcm_mspi *mspi, u16 offset)
>> +{
>> +       return bcma_read32(mspi->core, offset);
>> +}
>> +
>> +static inline void bcm_bcma_mspi_write(struct bcm_mspi *mspi, u16 offset,
>> +       u32 value)
>> +{
>> +       bcma_write32(mspi->core, offset, value);
>> +}
>> +
>> +/*
>> + * Probe routine for bcma devices.
>> + */
>>  static int bcm_mspi_bcma_probe(struct bcma_device *core)
>>  {
>>         struct bcm_mspi *data;
>> -       struct spi_master *master;
>>         int err;
>>
>>         dev_info(&core->dev, "BCM MSPI BCMA probe\n");
>>
>>         if (core->bus->drv_cc.core->id.rev != 42) {
>> -               pr_err("SPI on SoC with unsupported ChipCommon rev\n");
>> +               dev_err(&core->dev,
>> +                       "SPI on SoC with unsupported ChipCommon rev\n");
>>                 return -ENOTSUPP;
>>         }
>>
>> -       master = spi_alloc_master(&core->dev, sizeof(*data));
>> -       if (!master)
>> +       data = bcm_mspi_init(&core->dev);
>> +       if (!data)
>>                 return -ENOMEM;
>>
>> -       data = spi_master_get_devdata(master);
>> -       data->master = master;
>> +       data->mspi_read = bcm_bcma_mspi_read;
>> +       data->mspi_write = bcm_bcma_mspi_write;
>>         data->core = core;
>>
>> -       master->transfer_one = bcm_mspi_transfer_one;
>> -
>>         bcma_set_drvdata(core, data);
>>
>>         err = devm_spi_register_master(&core->dev, data->master);
>>         if (err) {
>> -               spi_master_put(master);
>> -               bcma_set_drvdata(core, NULL);
>> -               goto out;
>> +               spi_master_put(data->master);
>> +               return err;
>>         }
>>
>> -       /* Broadcom SoCs (at least with the CC rev 42) use SPI for flash only */
>> -       spi_new_device(master, &bcm_mspi_info);
> 
> Why are you removing the registration of the flash device? Won't this
> break bcm53xx's flash registration?

I'm actually not sure which spi device is being used here. What device
is "bcm53xxspiflash".. maybe Rafal can help? Then intention was to
select it from DT. Maybe something more needs to happen here though to
enable this though.

From bcm_mspi_init():
    /* SPI master will always use the SPI device(s) from DT. */
    master->dev.of_node = dev->of_node;

I think creating a spi device here would conflict with DT now. Here's
how I select m25p80 with non-bcma for example:

       mspi@18047000 {
               #address-cells = <1>;
               #size-cells = <0>;
               compatible = "brcm,mspi";
               reg = <0x18047000 0x1000>;

           flash: m25p80@0 {
                   compatible = "m25p80";
                   reg = <0>;
                   spi-max-frequency = <12500000>;
                   m25p,fast-read;
                   mode = <3>;
               };
       };


> 
>> -
>> -out:
>> -       return err;
>> -}
>> -
>> -static void bcm_mspi_bcma_remove(struct bcma_device *core)
>> -{
>> -       struct bcm_mspi *mspi = bcma_get_drvdata(core);
>> -
>> -       spi_unregister_master(mspi->master);
>> +       return 0;
>>  }
>>
>>  static struct bcma_driver bcm_mspi_bcma_driver = {
>>         .name           = KBUILD_MODNAME,
>> +       .drv = {
>> +               .of_match_table = bcm_bcma_mspi_dt,
>> +       },
>>         .id_table       = bcm_mspi_bcma_tbl,
>>         .probe          = bcm_mspi_bcma_probe,
>> -       .remove         = bcm_mspi_bcma_remove,
>>  };
>>
>> -static int __init bcm_mspi_module_init(void)
>> +static int __init bcm_mspi_bcma_module_init(void)
>>  {
>> -       int err = 0;
>> +       int err;
> 
> Unrelated change.
> 
>>
>>         err = bcma_driver_register(&bcm_mspi_bcma_driver);
>>         if (err)
>> @@ -291,13 +391,15 @@ static int __init bcm_mspi_module_init(void)
>>         return err;
>>  }
>>
>> -static void __exit bcm_mspi_module_exit(void)
>> +static void __exit bcm_mspi_bcma_module_exit(void)
>>  {
>>         bcma_driver_unregister(&bcm_mspi_bcma_driver);
>>  }
>>
>> -module_init(bcm_mspi_module_init);
>> -module_exit(bcm_mspi_module_exit);
>> +module_init(bcm_mspi_bcma_module_init);
>> +module_exit(bcm_mspi_bcma_module_exit);
>> +
>> +#endif
>>
>>  MODULE_DESCRIPTION("Broadcom MSPI SPI Controller driver");
>>  MODULE_AUTHOR("Rafał Miłecki <zajec5-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>");
>> --
> 
> 
> Regards
> Jonas
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