[3/3] mtd: spi-nor: Altera Quadspi Flash Controller v2 Platform driver

From: Matthew Gerlach <matthew.gerlach@linux.intel.com>

Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
---
 MAINTAINERS                                   |   1 +
 drivers/mtd/spi-nor/Kconfig                   |   5 +
 drivers/mtd/spi-nor/Makefile                  |   1 +
 drivers/mtd/spi-nor/altera-quadspi-platform.c | 137 ++++++++++++++++++++++++++
 4 files changed, 144 insertions(+)
 create mode 100644 drivers/mtd/spi-nor/altera-quadspi-platform.c

On 06/26/2017 06:13 PM, matthew.gerlach@linux.intel.com wrote:
> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>

Just wrap it into the Altera QSPI driver , no need for separate platform
driver IMO.

> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> ---
>  MAINTAINERS                                   |   1 +
>  drivers/mtd/spi-nor/Kconfig                   |   5 +
>  drivers/mtd/spi-nor/Makefile                  |   1 +
>  drivers/mtd/spi-nor/altera-quadspi-platform.c | 137 ++++++++++++++++++++++++++
>  4 files changed, 144 insertions(+)
>  create mode 100644 drivers/mtd/spi-nor/altera-quadspi-platform.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index ae33fa6..c32bb98 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -653,6 +653,7 @@ M:	Matthew Gerlach <matthew.gerlach@linux.intel.com>
>  L:	linux-mtd@lists.infradead.org
>  S:	Maintained
>  F:	drivers/mtd/spi-nor/altera-quadspi.c
> +F:	drivers/mtd/spi-nor/altera-quadspi-platform.c
>  F:	inclulde/linux/mtd/altera-quadspi.h
>  
>  ALTERA SYSTEM RESOURCE DRIVER FOR ARRIA10 DEVKIT
> diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
> index 89fe425..f3d5c01 100644
> --- a/drivers/mtd/spi-nor/Kconfig
> +++ b/drivers/mtd/spi-nor/Kconfig
> @@ -118,4 +118,9 @@ config SPI_ALTERA_QUADSPI
>          help
>            Enable support for version 2 of Altera Quad SPI Flash Controller.
>  
> +config SPI_ALTERA_QUADSPI_PLATFORM
> +	tristate "Platform support for Altera Quad SPI Flash Controller II"
> +	help
> +	  Platform driver support for  Altera Quad SPI Flash Controller II"
> +
>  endif # MTD_SPI_NOR
> diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
> index 024c6ac..042f87e 100644
> --- a/drivers/mtd/spi-nor/Makefile
> +++ b/drivers/mtd/spi-nor/Makefile
> @@ -10,4 +10,5 @@ obj-$(CONFIG_SPI_INTEL_SPI)	+= intel-spi.o
>  obj-$(CONFIG_SPI_INTEL_SPI_PLATFORM)	+= intel-spi-platform.o
>  obj-$(CONFIG_SPI_STM32_QUADSPI)	+= stm32-quadspi.o
>  obj-$(CONFIG_SPI_ALTERA_QUADSPI) += altera-quadspi.o
> +obj-$(CONFIG_SPI_ALTERA_QUADSPI_PLATFORM) += altera-quadspi-platform.o
>  
> diff --git a/drivers/mtd/spi-nor/altera-quadspi-platform.c b/drivers/mtd/spi-nor/altera-quadspi-platform.c
> new file mode 100644
> index 0000000..c8d2a47
> --- /dev/null
> +++ b/drivers/mtd/spi-nor/altera-quadspi-platform.c
> @@ -0,0 +1,137 @@
> +/*
> + * Copyright (C) 2014 Altera Corporation. All rights reserved.
> + * Copyright (C) 2017 Intel Corporation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + *
> + * 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 <linux/module.h>
> +#include <linux/mtd/altera-quadspi.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +
> +static int altera_quadspi_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	void __iomem *csr_base;
> +	void __iomem *data_base;
> +	void __iomem *window_base = NULL;
> +	u32 window_size = 0;
> +	u32 flags = 0;
> +	u32 bank;
> +	int ret;
> +	struct device_node *pp;
> +
> +	if (!np) {
> +		dev_err(dev, "no device found\n");
> +		return -ENODEV;
> +	}
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "avl_csr");
> +	csr_base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(csr_base)) {
> +		dev_err(dev, "%s: ERROR: failed to map csr base\n", __func__);
> +		return PTR_ERR(csr_base);
> +	}
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "avl_mem");
> +	data_base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(data_base)) {
> +		dev_err(dev, "%s: ERROR: failed to map data base\n", __func__);
> +		return PTR_ERR(data_base);
> +	}
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "avl_window");
> +	if (res) {
> +		window_base = NULL;
> +		window_base = devm_ioremap_resource(dev, res);
> +		if (IS_ERR(window_base)) {
> +			dev_err(dev, "%s: ERROR: failed to map window base\n",
> +				__func__);
> +			return PTR_ERR(data_base);
> +		}
> +
> +		of_property_read_u32(dev->of_node, "window-size", &window_size);
> +
> +		if (!window_size) {
> +			dev_err(dev,
> +				"alv_window defined, %s",
> +				"but no window-size defined\n");
> +			return -EINVAL;
> +		}
> +	}
> +
> +	if (of_property_read_bool(np, "read-bit-reverse"))
> +		flags |= ALTERA_QUADSPI_FL_BITREV_READ;
> +
> +	if (of_property_read_bool(np, "write-bit-reverse"))
> +		flags |= ALTERA_QUADSPI_FL_BITREV_WRITE;
> +
> +	ret = altera_quadspi_create(dev, csr_base, data_base,
> +				    window_base, (size_t)window_size, flags);
> +
> +	if (ret) {
> +		dev_err(dev, "failed to create qspi device\n");
> +		return ret;
> +	}
> +
> +	for_each_available_child_of_node(np, pp) {
> +		of_property_read_u32(pp, "reg", &bank);
> +		if (bank >= ALTERA_QUADSPI_MAX_NUM_FLASH_CHIP) {
> +			dev_err(dev, "bad reg value %u >= %u\n", bank,
> +				ALTERA_QUADSPI_MAX_NUM_FLASH_CHIP);
> +			goto error;
> +		}
> +
> +		if (altera_qspi_add_bank(dev, bank, pp)) {
> +			dev_err(dev, "failed to add bank %u\n", bank);
> +			goto error;
> +		}
> +	}
> +
> +	return 0;
> +error:
> +	altera_quadspi_remove_banks(dev);
> +	return -EIO;
> +}
> +
> +static int altera_quadspi_remove(struct platform_device *pdev)
> +{
> +	return altera_quadspi_remove_banks(&pdev->dev);
> +}
> +
> +static const struct of_device_id altera_quadspi_id_table[] = {
> +
> +	{ .compatible = "altr,quadspi-v2",},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, altera_quadspi_id_table);
> +
> +static struct platform_driver altera_quadspi_driver = {
> +	.driver = {
> +		.name = "altera_quadspi_platform",
> +		.of_match_table = altera_quadspi_id_table,
> +	},
> +	.probe = altera_quadspi_probe,
> +	.remove = altera_quadspi_remove,
> +};
> +module_platform_driver(altera_quadspi_driver);
> +
> +MODULE_AUTHOR("Viet Nga Dao <vndao@altera.com>");
> +MODULE_AUTHOR("Yong Sern Lau <lau.yong.sern@intel.com>");
> +MODULE_AUTHOR("Matthew Gerlach <matthew.gerlach@linux.intel.com>");
> +MODULE_DESCRIPTION("Altera QuadSPI Version 2 Platform Driver");
> +MODULE_LICENSE("GPL v2");
>

Hi Matthew,

[auto build test ERROR on spi-nor/next]
[also build test ERROR on next-20170627]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/matthew-gerlach-linux-intel-com/Altera-Quadspi-Controller-Version-2/20170627-120604
base:   git://github.com/spi-nor/linux next
config: um-allyesconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=um 

All errors (new ones prefixed by >>):

   arch/um/drivers/built-in.o: In function `vde_open_real':
   (.text+0xc9f1): warning: Using 'getgrnam' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
   arch/um/drivers/built-in.o: In function `vde_open_real':
   (.text+0xc83c): warning: Using 'getpwuid' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
   arch/um/drivers/built-in.o: In function `vde_open_real':
   (.text+0xcb55): warning: Using 'getaddrinfo' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
   arch/um/drivers/built-in.o: In function `pcap_nametoaddr':
   (.text+0x1d5e5): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
   arch/um/drivers/built-in.o: In function `pcap_nametonetaddr':
   (.text+0x1d685): warning: Using 'getnetbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
   arch/um/drivers/built-in.o: In function `pcap_nametoproto':
   (.text+0x1d8a5): warning: Using 'getprotobyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
   arch/um/drivers/built-in.o: In function `pcap_nametoport':
   (.text+0x1d6d7): warning: Using 'getservbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
   drivers/built-in.o: In function `altera_quadspi_probe':
>> drivers/mtd/spi-nor/altera-quadspi-platform.c:44: undefined reference to `devm_ioremap_resource'
   drivers/mtd/spi-nor/altera-quadspi-platform.c:51: undefined reference to `devm_ioremap_resource'
   drivers/mtd/spi-nor/altera-quadspi-platform.c:60: undefined reference to `devm_ioremap_resource'
   drivers/built-in.o: In function `img_ascii_lcd_probe':
   drivers/auxdisplay/img-ascii-lcd.c:386: undefined reference to `devm_ioremap_resource'
   collect2: error: ld returned 1 exit status

vim +44 drivers/mtd/spi-nor/altera-quadspi-platform.c

    38		if (!np) {
    39			dev_err(dev, "no device found\n");
    40			return -ENODEV;
    41		}
    42	
    43		res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "avl_csr");
  > 44		csr_base = devm_ioremap_resource(dev, res);
    45		if (IS_ERR(csr_base)) {
    46			dev_err(dev, "%s: ERROR: failed to map csr base\n", __func__);
    47			return PTR_ERR(csr_base);

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

On Tue, 27 Jun 2017, Marek Vasut wrote:

> On 06/26/2017 06:13 PM, matthew.gerlach@linux.intel.com wrote:
>> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
>
> Just wrap it into the Altera QSPI driver , no need for separate platform
> driver IMO.

Hi Marek,

I answered this question when you asked why the header file was necessary, 
but I think further discussion could be helpful, since this problem is 
becoming more prevelent.  The Altera Quadspi component is a soft IP in a
FPGA, and the processor using the component may or may not have device 
tree support compiled into the Linux kernel.  Since device tree support 
may or may not be available, the device tree specific code must be separated
from the core driver code.

One can certainly make the case, that device tree support could/should
be available everywhere, but the current reality is most x86 Linux
kernel configurations do not include device tree support.

For the record, I believe device trees, and more specifically device tree 
overlays, are the best way for Linux to use FPGAs, but I have to deal with 
the current realities.

Thanks again for all the great feedback.

Matthew Gerlach

>
>> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
>> ---
>>  MAINTAINERS                                   |   1 +
>>  drivers/mtd/spi-nor/Kconfig                   |   5 +
>>  drivers/mtd/spi-nor/Makefile                  |   1 +
>>  drivers/mtd/spi-nor/altera-quadspi-platform.c | 137 ++++++++++++++++++++++++++
>>  4 files changed, 144 insertions(+)
>>  create mode 100644 drivers/mtd/spi-nor/altera-quadspi-platform.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index ae33fa6..c32bb98 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -653,6 +653,7 @@ M:	Matthew Gerlach <matthew.gerlach@linux.intel.com>
>>  L:	linux-mtd@lists.infradead.org
>>  S:	Maintained
>>  F:	drivers/mtd/spi-nor/altera-quadspi.c
>> +F:	drivers/mtd/spi-nor/altera-quadspi-platform.c
>>  F:	inclulde/linux/mtd/altera-quadspi.h
>>
>>  ALTERA SYSTEM RESOURCE DRIVER FOR ARRIA10 DEVKIT
>> diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
>> index 89fe425..f3d5c01 100644
>> --- a/drivers/mtd/spi-nor/Kconfig
>> +++ b/drivers/mtd/spi-nor/Kconfig
>> @@ -118,4 +118,9 @@ config SPI_ALTERA_QUADSPI
>>          help
>>            Enable support for version 2 of Altera Quad SPI Flash Controller.
>>
>> +config SPI_ALTERA_QUADSPI_PLATFORM
>> +	tristate "Platform support for Altera Quad SPI Flash Controller II"
>> +	help
>> +	  Platform driver support for  Altera Quad SPI Flash Controller II"
>> +
>>  endif # MTD_SPI_NOR
>> diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
>> index 024c6ac..042f87e 100644
>> --- a/drivers/mtd/spi-nor/Makefile
>> +++ b/drivers/mtd/spi-nor/Makefile
>> @@ -10,4 +10,5 @@ obj-$(CONFIG_SPI_INTEL_SPI)	+= intel-spi.o
>>  obj-$(CONFIG_SPI_INTEL_SPI_PLATFORM)	+= intel-spi-platform.o
>>  obj-$(CONFIG_SPI_STM32_QUADSPI)	+= stm32-quadspi.o
>>  obj-$(CONFIG_SPI_ALTERA_QUADSPI) += altera-quadspi.o
>> +obj-$(CONFIG_SPI_ALTERA_QUADSPI_PLATFORM) += altera-quadspi-platform.o
>>
>> diff --git a/drivers/mtd/spi-nor/altera-quadspi-platform.c b/drivers/mtd/spi-nor/altera-quadspi-platform.c
>> new file mode 100644
>> index 0000000..c8d2a47
>> --- /dev/null
>> +++ b/drivers/mtd/spi-nor/altera-quadspi-platform.c
>> @@ -0,0 +1,137 @@
>> +/*
>> + * Copyright (C) 2014 Altera Corporation. All rights reserved.
>> + * Copyright (C) 2017 Intel Corporation. All rights reserved.
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope 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.
>> + *
>> + * 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 <linux/module.h>
>> +#include <linux/mtd/altera-quadspi.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_device.h>
>> +
>> +static int altera_quadspi_probe(struct platform_device *pdev)
>> +{
>> +	struct device_node *np = pdev->dev.of_node;
>> +	struct device *dev = &pdev->dev;
>> +	struct resource *res;
>> +	void __iomem *csr_base;
>> +	void __iomem *data_base;
>> +	void __iomem *window_base = NULL;
>> +	u32 window_size = 0;
>> +	u32 flags = 0;
>> +	u32 bank;
>> +	int ret;
>> +	struct device_node *pp;
>> +
>> +	if (!np) {
>> +		dev_err(dev, "no device found\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "avl_csr");
>> +	csr_base = devm_ioremap_resource(dev, res);
>> +	if (IS_ERR(csr_base)) {
>> +		dev_err(dev, "%s: ERROR: failed to map csr base\n", __func__);
>> +		return PTR_ERR(csr_base);
>> +	}
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "avl_mem");
>> +	data_base = devm_ioremap_resource(&pdev->dev, res);
>> +	if (IS_ERR(data_base)) {
>> +		dev_err(dev, "%s: ERROR: failed to map data base\n", __func__);
>> +		return PTR_ERR(data_base);
>> +	}
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "avl_window");
>> +	if (res) {
>> +		window_base = NULL;
>> +		window_base = devm_ioremap_resource(dev, res);
>> +		if (IS_ERR(window_base)) {
>> +			dev_err(dev, "%s: ERROR: failed to map window base\n",
>> +				__func__);
>> +			return PTR_ERR(data_base);
>> +		}
>> +
>> +		of_property_read_u32(dev->of_node, "window-size", &window_size);
>> +
>> +		if (!window_size) {
>> +			dev_err(dev,
>> +				"alv_window defined, %s",
>> +				"but no window-size defined\n");
>> +			return -EINVAL;
>> +		}
>> +	}
>> +
>> +	if (of_property_read_bool(np, "read-bit-reverse"))
>> +		flags |= ALTERA_QUADSPI_FL_BITREV_READ;
>> +
>> +	if (of_property_read_bool(np, "write-bit-reverse"))
>> +		flags |= ALTERA_QUADSPI_FL_BITREV_WRITE;
>> +
>> +	ret = altera_quadspi_create(dev, csr_base, data_base,
>> +				    window_base, (size_t)window_size, flags);
>> +
>> +	if (ret) {
>> +		dev_err(dev, "failed to create qspi device\n");
>> +		return ret;
>> +	}
>> +
>> +	for_each_available_child_of_node(np, pp) {
>> +		of_property_read_u32(pp, "reg", &bank);
>> +		if (bank >= ALTERA_QUADSPI_MAX_NUM_FLASH_CHIP) {
>> +			dev_err(dev, "bad reg value %u >= %u\n", bank,
>> +				ALTERA_QUADSPI_MAX_NUM_FLASH_CHIP);
>> +			goto error;
>> +		}
>> +
>> +		if (altera_qspi_add_bank(dev, bank, pp)) {
>> +			dev_err(dev, "failed to add bank %u\n", bank);
>> +			goto error;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +error:
>> +	altera_quadspi_remove_banks(dev);
>> +	return -EIO;
>> +}
>> +
>> +static int altera_quadspi_remove(struct platform_device *pdev)
>> +{
>> +	return altera_quadspi_remove_banks(&pdev->dev);
>> +}
>> +
>> +static const struct of_device_id altera_quadspi_id_table[] = {
>> +
>> +	{ .compatible = "altr,quadspi-v2",},
>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(of, altera_quadspi_id_table);
>> +
>> +static struct platform_driver altera_quadspi_driver = {
>> +	.driver = {
>> +		.name = "altera_quadspi_platform",
>> +		.of_match_table = altera_quadspi_id_table,
>> +	},
>> +	.probe = altera_quadspi_probe,
>> +	.remove = altera_quadspi_remove,
>> +};
>> +module_platform_driver(altera_quadspi_driver);
>> +
>> +MODULE_AUTHOR("Viet Nga Dao <vndao@altera.com>");
>> +MODULE_AUTHOR("Yong Sern Lau <lau.yong.sern@intel.com>");
>> +MODULE_AUTHOR("Matthew Gerlach <matthew.gerlach@linux.intel.com>");
>> +MODULE_DESCRIPTION("Altera QuadSPI Version 2 Platform Driver");
>> +MODULE_LICENSE("GPL v2");
>>
>
>
> -- 
> Best regards,
> Marek Vasut
>

On 06/27/2017 05:15 PM, matthew.gerlach@linux.intel.com wrote:
> 
> 
> On Tue, 27 Jun 2017, Marek Vasut wrote:
> 
>> On 06/26/2017 06:13 PM, matthew.gerlach@linux.intel.com wrote:
>>> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
>>
>> Just wrap it into the Altera QSPI driver , no need for separate platform
>> driver IMO.
> 
> Hi Marek,
> 
> I answered this question when you asked why the header file was
> necessary, but I think further discussion could be helpful, since this
> problem is becoming more prevelent.  The Altera Quadspi component is a
> soft IP in a
> FPGA, and the processor using the component may or may not have device
> tree support compiled into the Linux kernel.  Since device tree support
> may or may not be available, the device tree specific code must be
> separated
> from the core driver code.

I see, that's fine, although there is no PCIe or other support in this
submission. Is that planned ?

> One can certainly make the case, that device tree support could/should
> be available everywhere, but the current reality is most x86 Linux
> kernel configurations do not include device tree support.
> 
> For the record, I believe device trees, and more specifically device
> tree overlays, are the best way for Linux to use FPGAs, but I have to
> deal with the current realities.
> 
> Thanks again for all the great feedback.
> 
> Matthew Gerlach

[...]

On Tue, 27 Jun 2017, Marek Vasut wrote:

> On 06/27/2017 05:15 PM, matthew.gerlach@linux.intel.com wrote:
>>
>>
>> On Tue, 27 Jun 2017, Marek Vasut wrote:
>>
>>> On 06/26/2017 06:13 PM, matthew.gerlach@linux.intel.com wrote:
>>>> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
>>>
>>> Just wrap it into the Altera QSPI driver , no need for separate platform
>>> driver IMO.
>>
>> Hi Marek,
>>
>> I answered this question when you asked why the header file was
>> necessary, but I think further discussion could be helpful, since this
>> problem is becoming more prevelent.  The Altera Quadspi component is a
>> soft IP in a
>> FPGA, and the processor using the component may or may not have device
>> tree support compiled into the Linux kernel.  Since device tree support
>> may or may not be available, the device tree specific code must be
>> separated
>> from the core driver code.
>
> I see, that's fine, although there is no PCIe or other support in this
> submission. Is that planned ?

You probably would not see a PCIe driver for a card with a FPGA that would 
only have the Altera Quadspi component on it.  Usually a FPGA has several 
components, each requiring their own driver which are considered 
sub-drivers of the PCIe driver.  I will be adding Altera Quadspi support 
to the Intel-FPGA PCIe driver that is currently under review.  We have 
also seen people use the Altera Quadspi with a NIOS-II soft processor, and 
I expect someone would want to use the component with ARM SOCFPGAs.

Matthew Gerlach

>
>> One can certainly make the case, that device tree support could/should
>> be available everywhere, but the current reality is most x86 Linux
>> kernel configurations do not include device tree support.
>>
>> For the record, I believe device trees, and more specifically device
>> tree overlays, are the best way for Linux to use FPGAs, but I have to
>> deal with the current realities.
>>
>> Thanks again for all the great feedback.
>>
>> Matthew Gerlach
>
> [...]
>
> -- 
> Best regards,
> Marek Vasut
>