Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
---
Documentation/DocBook/drm.tmpl | 118 ++++++++++++++++++++++++-----------------
1 file changed, 70 insertions(+), 48 deletions(-)
Changes since v1:
- Document manual IRQ registration
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 91ee107..a608094 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -186,11 +186,12 @@
<varlistentry>
<term>DRIVER_HAVE_IRQ</term><term>DRIVER_IRQ_SHARED</term>
<listitem><para>
- DRIVER_HAVE_IRQ indicates whether the driver has an IRQ handler.
The
- DRM core will automatically register an interrupt handler when
the
- flag is set. DRIVER_IRQ_SHARED indicates whether the device &
- handler support shared IRQs (note that this is required of PCI
- drivers).
+ DRIVER_HAVE_IRQ indicates whether the driver has an IRQ handler
+ managed by the DRM Core. The core will support simple IRQ handler
+ installation when the flag is set. The installation process is
+ described in <xref linkend="drm-irq-registration"/>.</para>
+ <para>DRIVER_IRQ_SHARED indicates whether the device &
handler
+ support shared IRQs (note that this is required of PCI drivers).
</para></listitem>
</varlistentry>
<varlistentry>
@@ -344,50 +345,71 @@ char *date;</synopsis>
The DRM core tries to facilitate IRQ handler registration and
unregistration by providing <function>drm_irq_install</function> and
<function>drm_irq_uninstall</function> functions. Those functions
only
- support a single interrupt per device.
- </para>
- <!--!Fdrivers/char/drm/drm_irq.c drm_irq_install-->
- <para>
- Both functions get the device IRQ by calling
- <function>drm_dev_to_irq</function>. This inline function will call a
- bus-specific operation to retrieve the IRQ number. For platform
devices,
- <function>platform_get_irq</function>(..., 0) is used to retrieve the
- IRQ number.
- </para>
- <para>
- <function>drm_irq_install</function> starts by calling the
- <methodname>irq_preinstall</methodname> driver operation. The
operation
- is optional and must make sure that the interrupt will not get fired
by
- clearing all pending interrupt flags or disabling the interrupt.
- </para>
- <para>
- The IRQ will then be requested by a call to
- <function>request_irq</function>. If the DRIVER_IRQ_SHARED driver
- feature flag is set, a shared (IRQF_SHARED) IRQ handler will be
- requested.
- </para>
- <para>
- The IRQ handler function must be provided as the mandatory
irq_handler
- driver operation. It will get passed directly to
- <function>request_irq</function> and thus has the same prototype as
all
- IRQ handlers. It will get called with a pointer to the DRM device as
the
- second argument.
- </para>
- <para>
- Finally the function calls the optional
- <methodname>irq_postinstall</methodname> driver operation. The
operation
- usually enables interrupts (excluding the vblank interrupt, which is
- enabled separately), but drivers may choose to enable/disable
interrupts
- at a different time.
- </para>
- <para>
- <function>drm_irq_uninstall</function> is similarly used to
uninstall an
- IRQ handler. It starts by waking up all processes waiting on a vblank
- interrupt to make sure they don't hang, and then calls the optional
- <methodname>irq_uninstall</methodname> driver operation. The
operation
- must disable all hardware interrupts. Finally the function frees the
IRQ
- by calling <function>free_irq</function>.
+ support a single interrupt per device, devices that use more than one
+ IRQs need to be handled manually.
</para>
+ <sect4>
+ <title>Managed IRQ Registration</title>
+ <para>
+ Both the <function>drm_irq_install</function> and
+ <function>drm_irq_uninstall</function> functions get the device IRQ
by
+ calling <function>drm_dev_to_irq</function>. This inline function
will
+ call a bus-specific operation to retrieve the IRQ number. For
platform
+ devices, <function>platform_get_irq</function>(..., 0) is used to
+ retrieve the IRQ number.
+ </para>
+ <para>
+ <function>drm_irq_install</function> starts by calling the
+ <methodname>irq_preinstall</methodname> driver operation. The
operation
+ is optional and must make sure that the interrupt will not get
fired by
+ clearing all pending interrupt flags or disabling the interrupt.
+ </para>
+ <para>
+ The IRQ will then be requested by a call to
+ <function>request_irq</function>. If the DRIVER_IRQ_SHARED driver
+ feature flag is set, a shared (IRQF_SHARED) IRQ handler will be
+ requested.
+ </para>
+ <para>
+ The IRQ handler function must be provided as the mandatory
irq_handler
+ driver operation. It will get passed directly to
+ <function>request_irq</function> and thus has the same prototype
as all
+ IRQ handlers. It will get called with a pointer to the DRM device
as the
+ second argument.
+ </para>
+ <para>
+ Finally the function calls the optional
+ <methodname>irq_postinstall</methodname> driver operation. The
operation
+ usually enables interrupts (excluding the vblank interrupt, which
is
+ enabled separately), but drivers may choose to enable/disable
interrupts
+ at a different time.
+ </para>
+ <para>
+ <function>drm_irq_uninstall</function> is similarly used to
uninstall an
+ IRQ handler. It starts by waking up all processes waiting on a
vblank
+ interrupt to make sure they don't hang, and then calls the optional
+ <methodname>irq_uninstall</methodname> driver operation. The
operation
+ must disable all hardware interrupts. Finally the function frees
the IRQ
+ by calling <function>free_irq</function>.
+ </para>
+ </sect4>
+ <sect4>
+ <title>Manual IRQ Registration</title>
+ <para>
+ Drivers that require multiple interrupt handlers can't use the
managed
+ IRQ registration functions. In that case IRQs must be registered
and
+ unregistered manually (usually with the
<function>request_irq</function>
+ and <function>free_irq</function> functions, or their devm_*
equivalent).
+ </para>
+ <para>
+ When manually registering IRQs, drivers must not set the
DRIVER_HAVE_IRQ
+ driver feature flag, and must not provide the
+ <methodname>irq_handler</methodname> driver operation. They must
set the
+ <structname>drm_device</structname>
<structfield>irq_enabled</structfield>
+ field to 1 upon registration of the IRQs, and clear it to 0 after
+ unregistering the IRQs.
+ </para>
+ </sect4>
</sect3>
<sect3>
<title>Memory Manager Initialization</title>
--
Regards,
Laurent Pinchart
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