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[PATCH v5 0/4] Allow ISA-style drivers on modern systems

Started byWilliam Breathitt Gray <vilhelm.gray@gmail.com>
First post2016-05-28 00:10 +0200
Last post2016-05-31 10:50 +0200
Articles 5 — 3 participants

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  [PATCH v5 0/4] Allow ISA-style drivers on modern systems William Breathitt Gray <vilhelm.gray@gmail.com> - 2016-05-28 00:10 +0200
    [PATCH v5 1/4] isa: Allow ISA-style drivers on modern systems William Breathitt Gray <vilhelm.gray@gmail.com> - 2016-05-28 00:10 +0200
      Re: [PATCH v5 1/4] isa: Allow ISA-style drivers on modern systems Linus Torvalds <torvalds@linux-foundation.org> - 2016-05-28 21:40 +0200
    [PATCH v5 2/4] gpio: Allow PC/104 devices on X86_64 William Breathitt Gray <vilhelm.gray@gmail.com> - 2016-05-28 00:10 +0200
      Re: [PATCH v5 2/4] gpio: Allow PC/104 devices on X86_64 Linus Walleij <linus.walleij@linaro.org> - 2016-05-31 10:50 +0200

#1408335 — [PATCH v5 0/4] Allow ISA-style drivers on modern systems

FromWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Date2016-05-28 00:10 +0200
Subject[PATCH v5 0/4] Allow ISA-style drivers on modern systems
Message-ID<rDy77-FP-5@gated-at.bofh.it>
Changes in v5:
  - Add explicit X86 dependency to CONFIG_STX104 and CONFIG_EBC_C384_WDT
    since these drivers were developed with X86 architectures in mind

Changes in v4:
  - Remove unnecessary explicit "default n" from the X86 ISA_BUS Kconfig
    option since Kconfig options are disabled by default

Changes in v3:
  - Remove redundant X86 dependency from the X86 ISA_BUS Kconfig option

Changes in v2:
  - Adjusted preprocessor compilation conditional in include/linux/isa.h
    to use CONFIG_ISA_BUS_API in order to link the correct ISA bus
    driver function definitions when available
  - Move ISA_BUS_API Kconfig option to arch/Kconfig, thus making it
    available to all architectures instead of just X86
  - X86 ISA_BUS Kconfig option should be disabled by default; ISA
    devices typically do not have a way to be probed, so users should
    be required to explicitly enable ISA bus driver support, lest a
    selected driver be loaded with the misguided expectation of a safe
    hardware probe

Several modern devices, such as PC/104 cards, are expected to run on
modern systems via an ISA bus interface. Since ISA is a legacy interface
for most modern architectures, ISA support should remain disabled in
general. Support for ISA-style drivers should be enabled on a per driver
basis.

To allow ISA-style drivers on modern systems, this patchset introduces
the ISA_BUS_API and ISA_BUS Kconfig options. The ISA bus driver will now
build conditionally on the ISA_BUS_API Kconfig option, which defaults to
the legacy ISA Kconfig option. The ISA_BUS Kconfig option allows the
ISA_BUS_API Kconfig option to be selected on architectures which do not
enable ISA (e.g. X86_64).

The ISA_BUS Kconfig option is currently only implemented for X86
architectures. Other architectures may have their own ISA_BUS Kconfig
option added as required.

An earlier attempt to allow the ISA bus driver to build for X86_64 took
an inappropriate approach resulting in legacy ISA drivers becoming
enabled unconditionally on untested and unsupported architectures.
Commit 51e68d055cba ("x86 isa: add back X86_32 dependency on
CONFIG_ISA"), added to restrict the ISA bus driver to only X86_32,
causes several drivers intended for X86_64 to be restricted to X86_32 as
well.

This patchset replaces the ISA Kconfig option dependency of several
drivers to ISA_BUS_API, so that they may build for X86_64 as intended.
The respective drivers are as follows:
    * ACCES 104-IDIO-16 GPIO driver
    * ACCES 104-IDI-48 GPIO driver
    * ACCES 104-DIO-48E GPIO driver
    * Apex Embedded Systems STX104 DAC driver
    * WinSystems EBC-C384 watchdog timer driver
    * WinSystems WS16C48 GPIO driver

William Breathitt Gray (4):
  isa: Allow ISA-style drivers on modern systems
  gpio: Allow PC/104 devices on X86_64
  iio: stx104: Allow build for X86_64
  watchdog: ebc-c384_wdt: Allow build for X86_64

 arch/Kconfig             | 3 +++
 arch/x86/Kconfig         | 9 +++++++++
 drivers/base/Makefile    | 2 +-
 drivers/gpio/Kconfig     | 8 ++++----
 drivers/iio/dac/Kconfig  | 2 +-
 drivers/watchdog/Kconfig | 2 +-
 include/linux/isa.h      | 2 +-
 7 files changed, 20 insertions(+), 8 deletions(-)

-- 
2.7.3

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#1408336 — [PATCH v5 1/4] isa: Allow ISA-style drivers on modern systems

FromWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Date2016-05-28 00:10 +0200
Subject[PATCH v5 1/4] isa: Allow ISA-style drivers on modern systems
Message-ID<rDy77-FP-13@gated-at.bofh.it>
In reply to#1408335
Several modern devices, such as PC/104 cards, are expected to run on
modern systems via an ISA bus interface. Since ISA is a legacy interface
for most modern architectures, ISA support should remain disabled in
general. Support for ISA-style drivers should be enabled on a per driver
basis.

To allow ISA-style drivers on modern systems, this patch introduces the
ISA_BUS_API and ISA_BUS Kconfig options. The ISA bus driver will now
build conditionally on the ISA_BUS_API Kconfig option, which defaults to
the legacy ISA Kconfig option. The ISA_BUS Kconfig option allows the
ISA_BUS_API Kconfig option to be selected on architectures which do not
enable ISA (e.g. X86_64).

The ISA_BUS Kconfig option is currently only implemented for X86
architectures. Other architectures may have their own ISA_BUS Kconfig
options added as required.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 arch/Kconfig          | 3 +++
 arch/x86/Kconfig      | 9 +++++++++
 drivers/base/Makefile | 2 +-
 include/linux/isa.h   | 2 +-
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index b16e74e..9d9942f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -598,6 +598,9 @@ config HAVE_STACK_VALIDATION
 	  Architecture supports the 'objtool check' host tool command, which
 	  performs compile-time stack metadata validation.
 
+config ISA_BUS_API
+	def_bool ISA
+
 #
 # ABI hall of shame
 #
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 0a7b885..d9a94da 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2439,6 +2439,15 @@ config PCI_CNB20LE_QUIRK
 
 source "drivers/pci/Kconfig"
 
+config ISA_BUS
+	bool "ISA-style bus support on modern systems" if EXPERT
+	select ISA_BUS_API
+	help
+	  Enables ISA-style drivers on modern systems. This is necessary to
+	  support PC/104 devices on X86_64 platforms.
+
+	  If unsure, say N.
+
 # x86_64 have no ISA slots, but can have ISA-style DMA.
 config ISA_DMA_API
 	bool "ISA-style DMA support" if (X86_64 && EXPERT)
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 6b2a84e..2609ba2 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -10,7 +10,7 @@ obj-$(CONFIG_DMA_CMA) += dma-contiguous.o
 obj-y			+= power/
 obj-$(CONFIG_HAS_DMA)	+= dma-mapping.o
 obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
-obj-$(CONFIG_ISA)	+= isa.o
+obj-$(CONFIG_ISA_BUS_API)	+= isa.o
 obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
 obj-$(CONFIG_NUMA)	+= node.o
 obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o
diff --git a/include/linux/isa.h b/include/linux/isa.h
index 5ab8528..384ab9b 100644
--- a/include/linux/isa.h
+++ b/include/linux/isa.h
@@ -22,7 +22,7 @@ struct isa_driver {
 
 #define to_isa_driver(x) container_of((x), struct isa_driver, driver)
 
-#ifdef CONFIG_ISA
+#ifdef CONFIG_ISA_BUS_API
 int isa_register_driver(struct isa_driver *, unsigned int);
 void isa_unregister_driver(struct isa_driver *);
 #else
-- 
2.7.3

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#1408507 — Re: [PATCH v5 1/4] isa: Allow ISA-style drivers on modern systems

FromLinus Torvalds <torvalds@linux-foundation.org>
Date2016-05-28 21:40 +0200
SubjectRe: [PATCH v5 1/4] isa: Allow ISA-style drivers on modern systems
Message-ID<rDSfv-4vZ-11@gated-at.bofh.it>
In reply to#1408336
On Fri, May 27, 2016 at 3:08 PM, William Breathitt Gray
<vilhelm.gray@gmail.com> wrote:
> Several modern devices, such as PC/104 cards, are expected to run on
> modern systems via an ISA bus interface. Since ISA is a legacy interface
> for most modern architectures, ISA support should remain disabled in
> general. Support for ISA-style drivers should be enabled on a per driver
> basis.
>
> To allow ISA-style drivers on modern systems, this patch introduces the
> ISA_BUS_API and ISA_BUS Kconfig options. The ISA bus driver will now
> build conditionally on the ISA_BUS_API Kconfig option, which defaults to
> the legacy ISA Kconfig option. The ISA_BUS Kconfig option allows the
> ISA_BUS_API Kconfig option to be selected on architectures which do not
> enable ISA (e.g. X86_64).
>
> The ISA_BUS Kconfig option is currently only implemented for X86
> architectures. Other architectures may have their own ISA_BUS Kconfig
> options added as required.
>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>

This version seems fine and safe. I didn't see the other patches in
the series (not cc'd to me), but at least this one would seem to do
the right thing and expose part of the ISA code without causing other
architectures to possibly lose it.

              Linus

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#1408337 — [PATCH v5 2/4] gpio: Allow PC/104 devices on X86_64

FromWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Date2016-05-28 00:10 +0200
Subject[PATCH v5 2/4] gpio: Allow PC/104 devices on X86_64
Message-ID<rDy78-FP-31@gated-at.bofh.it>
In reply to#1408335
With the introduction of the ISA_BUS_API Kconfig option, ISA-style
drivers may be built for X86_64 architectures. This patch changes the
ISA Kconfig option dependency of the PC/104 drivers to ISA_BUS_API, thus
allowing them to build for X86_64 as they are expected to.

Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/Kconfig | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 48da857..dc6da77 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -530,7 +530,7 @@ menu "Port-mapped I/O GPIO drivers"
 
 config GPIO_104_DIO_48E
 	tristate "ACCES 104-DIO-48E GPIO support"
-	depends on ISA
+	depends on ISA_BUS_API
 	select GPIOLIB_IRQCHIP
 	help
 	  Enables GPIO support for the ACCES 104-DIO-48E series (104-DIO-48E,
@@ -540,7 +540,7 @@ config GPIO_104_DIO_48E
 
 config GPIO_104_IDIO_16
 	tristate "ACCES 104-IDIO-16 GPIO support"
-	depends on ISA
+	depends on ISA_BUS_API
 	select GPIOLIB_IRQCHIP
 	help
 	  Enables GPIO support for the ACCES 104-IDIO-16 family (104-IDIO-16,
@@ -551,7 +551,7 @@ config GPIO_104_IDIO_16
 
 config GPIO_104_IDI_48
 	tristate "ACCES 104-IDI-48 GPIO support"
-	depends on ISA
+	depends on ISA_BUS_API
 	select GPIOLIB_IRQCHIP
 	help
 	  Enables GPIO support for the ACCES 104-IDI-48 family (104-IDI-48A,
@@ -627,7 +627,7 @@ config GPIO_TS5500
 
 config GPIO_WS16C48
 	tristate "WinSystems WS16C48 GPIO support"
-	depends on ISA
+	depends on ISA_BUS_API
 	select GPIOLIB_IRQCHIP
 	help
 	  Enables GPIO support for the WinSystems WS16C48. The base port
-- 
2.7.3

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#1409996 — Re: [PATCH v5 2/4] gpio: Allow PC/104 devices on X86_64

FromLinus Walleij <linus.walleij@linaro.org>
Date2016-05-31 10:50 +0200
SubjectRe: [PATCH v5 2/4] gpio: Allow PC/104 devices on X86_64
Message-ID<rENx7-m9-15@gated-at.bofh.it>
In reply to#1408337
On Sat, May 28, 2016 at 12:08 AM, William Breathitt Gray
<vilhelm.gray@gmail.com> wrote:

> With the introduction of the ISA_BUS_API Kconfig option, ISA-style
> drivers may be built for X86_64 architectures. This patch changes the
> ISA Kconfig option dependency of the PC/104 drivers to ISA_BUS_API, thus
> allowing them to build for X86_64 as they are expected to.
>
> Cc: Alexandre Courbot <gnurou@gmail.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Or should I apply this directly to the GPIO tree?

Yours,
Linus Walleij

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