OMAP: hwmod: improve documentation, clean up function names
This patch: - adds more documentation to the hwmod code - fixes some documentation typos elsewhere in the file - changes the _sysc_*() function names to appear in (verb, noun) order, to match the rest of the function names. This patch should not result in any functional change. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Kevin Hilman <khilman@deeprootsystems.com> Cc: Benoît Cousson <b-cousson@ti.com>
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Paul Walmsley
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74ff3a68ed
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@ -13,10 +13,102 @@
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This code manages "OMAP modules" (on-chip devices) and their
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* integration with Linux device driver and bus code.
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* Introduction
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* ------------
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* One way to view an OMAP SoC is as a collection of largely unrelated
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* IP blocks connected by interconnects. The IP blocks include
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* devices such as ARM processors, audio serial interfaces, UARTs,
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* etc. Some of these devices, like the DSP, are created by TI;
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* others, like the SGX, largely originate from external vendors. In
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* TI's documentation, on-chip devices are referred to as "OMAP
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* modules." Some of these IP blocks are identical across several
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* OMAP versions. Others are revised frequently.
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*
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* References:
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* These OMAP modules are tied together by various interconnects.
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* Most of the address and data flow between modules is via OCP-based
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* interconnects such as the L3 and L4 buses; but there are other
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* interconnects that distribute the hardware clock tree, handle idle
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* and reset signaling, supply power, and connect the modules to
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* various pads or balls on the OMAP package.
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*
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* OMAP hwmod provides a consistent way to describe the on-chip
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* hardware blocks and their integration into the rest of the chip.
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* This description can be automatically generated from the TI
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* hardware database. OMAP hwmod provides a standard, consistent API
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* to reset, enable, idle, and disable these hardware blocks. And
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* hwmod provides a way for other core code, such as the Linux device
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* code or the OMAP power management and address space mapping code,
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* to query the hardware database.
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*
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* Using hwmod
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* -----------
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* Drivers won't call hwmod functions directly. That is done by the
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* omap_device code, and in rare occasions, by custom integration code
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* in arch/arm/ *omap*. The omap_device code includes functions to
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* build a struct platform_device using omap_hwmod data, and that is
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* currently how hwmod data is communicated to drivers and to the
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* Linux driver model. Most drivers will call omap_hwmod functions only
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* indirectly, via pm_runtime*() functions.
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*
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* From a layering perspective, here is where the OMAP hwmod code
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* fits into the kernel software stack:
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*
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* +-------------------------------+
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* | Device driver code |
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* | (e.g., drivers/) |
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* +-------------------------------+
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* | Linux driver model |
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* | (platform_device / |
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* | platform_driver data/code) |
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* +-------------------------------+
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* | OMAP core-driver integration |
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* |(arch/arm/mach-omap2/devices.c)|
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* +-------------------------------+
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* | omap_device code |
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* | (../plat-omap/omap_device.c) |
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* +-------------------------------+
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* ----> | omap_hwmod code/data | <-----
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* | (../mach-omap2/omap_hwmod*) |
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* +-------------------------------+
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* | OMAP clock/PRCM/register fns |
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* | (__raw_{read,write}l, clk*) |
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* +-------------------------------+
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*
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* Device drivers should not contain any OMAP-specific code or data in
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* them. They should only contain code to operate the IP block that
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* the driver is responsible for. This is because these IP blocks can
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* also appear in other SoCs, either from TI (such as DaVinci) or from
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* other manufacturers; and drivers should be reusable across other
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* platforms.
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*
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* The OMAP hwmod code also will attempt to reset and idle all on-chip
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* devices upon boot. The goal here is for the kernel to be
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* completely self-reliant and independent from bootloaders. This is
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* to ensure a repeatable configuration, both to ensure consistent
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* runtime behavior, and to make it easier for others to reproduce
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* bugs.
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*
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* OMAP module activity states
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* ---------------------------
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* The hwmod code considers modules to be in one of several activity
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* states. IP blocks start out in an UNKNOWN state, then once they
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* are registered via the hwmod code, proceed to the REGISTERED state.
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* Once their clock names are resolved to clock pointers, the module
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* enters the CLKS_INITED state; and finally, once the module has been
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* reset and the integration registers programmed, the INITIALIZED state
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* is entered. The hwmod code will then place the module into either
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* the IDLE state to save power, or in the case of a critical system
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* module, the ENABLED state.
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*
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* OMAP core integration code can then call omap_hwmod*() functions
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* directly to move the module between the IDLE, ENABLED, and DISABLED
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* states, as needed. This is done during both the PM idle loop, and
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* in the OMAP core integration code's implementation of the PM runtime
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* functions.
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*
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* References
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* ----------
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* This is a partial list.
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* - OMAP2420 Multimedia Processor Silicon Revision 2.1.1, 2.2 (SWPU064)
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* - OMAP2430 Multimedia Device POP Silicon Revision 2.1 (SWPU090)
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* - OMAP34xx Multimedia Device Silicon Revision 3.1 (SWPU108)
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@ -654,7 +746,7 @@ static void __iomem *_find_mpu_rt_base(struct omap_hwmod *oh, u8 index)
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}
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/**
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* _sysc_enable - try to bring a module out of idle via OCP_SYSCONFIG
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* _enable_sysc - try to bring a module out of idle via OCP_SYSCONFIG
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* @oh: struct omap_hwmod *
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*
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* If module is marked as SWSUP_SIDLE, force the module out of slave
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@ -662,7 +754,7 @@ static void __iomem *_find_mpu_rt_base(struct omap_hwmod *oh, u8 index)
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* as SWSUP_MSUSPEND, force the module out of master standby;
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* otherwise, configure it for smart-standby. No return value.
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*/
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static void _sysc_enable(struct omap_hwmod *oh)
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static void _enable_sysc(struct omap_hwmod *oh)
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{
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u8 idlemode, sf;
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u32 v;
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@ -708,7 +800,7 @@ static void _sysc_enable(struct omap_hwmod *oh)
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}
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/**
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* _sysc_idle - try to put a module into idle via OCP_SYSCONFIG
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* _idle_sysc - try to put a module into idle via OCP_SYSCONFIG
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* @oh: struct omap_hwmod *
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*
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* If module is marked as SWSUP_SIDLE, force the module into slave
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@ -716,7 +808,7 @@ static void _sysc_enable(struct omap_hwmod *oh)
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* as SWSUP_MSUSPEND, force the module into master standby; otherwise,
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* configure it for smart-standby. No return value.
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*/
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static void _sysc_idle(struct omap_hwmod *oh)
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static void _idle_sysc(struct omap_hwmod *oh)
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{
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u8 idlemode, sf;
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u32 v;
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@ -743,13 +835,13 @@ static void _sysc_idle(struct omap_hwmod *oh)
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}
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/**
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* _sysc_shutdown - force a module into idle via OCP_SYSCONFIG
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* _shutdown_sysc - force a module into idle via OCP_SYSCONFIG
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* @oh: struct omap_hwmod *
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*
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* Force the module into slave idle and master suspend. No return
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* value.
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*/
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static void _sysc_shutdown(struct omap_hwmod *oh)
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static void _shutdown_sysc(struct omap_hwmod *oh)
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{
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u32 v;
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u8 sf;
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@ -1071,8 +1163,11 @@ dis_opt_clks:
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* @oh: struct omap_hwmod *
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*
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* Enables an omap_hwmod @oh such that the MPU can access the hwmod's
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* register target. Returns -EINVAL if the hwmod is in the wrong
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* state or passes along the return value of _wait_target_ready().
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* register target. (This function has a full name --
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* _omap_hwmod_enable() rather than simply _enable() -- because it is
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* currently required by the pm34xx.c idle loop.) Returns -EINVAL if
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* the hwmod is in the wrong state or passes along the return value of
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* _wait_target_ready().
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*/
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int _omap_hwmod_enable(struct omap_hwmod *oh)
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{
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@ -1110,7 +1205,7 @@ int _omap_hwmod_enable(struct omap_hwmod *oh)
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if (oh->class->sysc) {
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if (!(oh->_int_flags & _HWMOD_SYSCONFIG_LOADED))
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_update_sysc_cache(oh);
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_sysc_enable(oh);
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_enable_sysc(oh);
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}
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} else {
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pr_debug("omap_hwmod: %s: _wait_target_ready: %d\n",
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@ -1121,12 +1216,14 @@ int _omap_hwmod_enable(struct omap_hwmod *oh)
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}
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/**
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* _idle - idle an omap_hwmod
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* _omap_hwmod_idle - idle an omap_hwmod
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* @oh: struct omap_hwmod *
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*
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* Idles an omap_hwmod @oh. This should be called once the hwmod has
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* no further work. Returns -EINVAL if the hwmod is in the wrong
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* state or returns 0.
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* no further work. (This function has a full name --
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* _omap_hwmod_idle() rather than simply _idle() -- because it is
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* currently required by the pm34xx.c idle loop.) Returns -EINVAL if
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* the hwmod is in the wrong state or returns 0.
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*/
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int _omap_hwmod_idle(struct omap_hwmod *oh)
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{
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@ -1139,7 +1236,7 @@ int _omap_hwmod_idle(struct omap_hwmod *oh)
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pr_debug("omap_hwmod: %s: idling\n", oh->name);
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if (oh->class->sysc)
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_sysc_idle(oh);
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_idle_sysc(oh);
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_del_initiator_dep(oh, mpu_oh);
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_disable_clocks(oh);
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@ -1169,7 +1266,7 @@ static int _shutdown(struct omap_hwmod *oh)
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pr_debug("omap_hwmod: %s: disabling\n", oh->name);
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if (oh->class->sysc)
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_sysc_shutdown(oh);
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_shutdown_sysc(oh);
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/*
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* If an IP contains only one HW reset line, then assert it
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@ -1262,7 +1359,7 @@ static int _setup(struct omap_hwmod *oh, void *data)
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*/
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if (oh->class->sysc) {
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_update_sysc_cache(oh);
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_sysc_enable(oh);
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_enable_sysc(oh);
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}
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}
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@ -1518,7 +1615,7 @@ int omap_hwmod_unregister(struct omap_hwmod *oh)
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* omap_hwmod_enable - enable an omap_hwmod
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* @oh: struct omap_hwmod *
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*
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* Enable an omap_hwomd @oh. Intended to be called by omap_device_enable().
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* Enable an omap_hwmod @oh. Intended to be called by omap_device_enable().
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* Returns -EINVAL on error or passes along the return value from _enable().
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*/
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int omap_hwmod_enable(struct omap_hwmod *oh)
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@ -1540,7 +1637,7 @@ int omap_hwmod_enable(struct omap_hwmod *oh)
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* omap_hwmod_idle - idle an omap_hwmod
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* @oh: struct omap_hwmod *
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*
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* Idle an omap_hwomd @oh. Intended to be called by omap_device_idle().
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* Idle an omap_hwmod @oh. Intended to be called by omap_device_idle().
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* Returns -EINVAL on error or passes along the return value from _idle().
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*/
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int omap_hwmod_idle(struct omap_hwmod *oh)
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@ -1559,7 +1656,7 @@ int omap_hwmod_idle(struct omap_hwmod *oh)
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* omap_hwmod_shutdown - shutdown an omap_hwmod
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* @oh: struct omap_hwmod *
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*
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* Shutdown an omap_hwomd @oh. Intended to be called by
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* Shutdown an omap_hwmod @oh. Intended to be called by
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* omap_device_shutdown(). Returns -EINVAL on error or passes along
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* the return value from _shutdown().
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*/
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@ -14,19 +14,16 @@
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*
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* These headers and macros are used to define OMAP on-chip module
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* data and their integration with other OMAP modules and Linux.
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*
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* References:
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* - OMAP2420 Multimedia Processor Silicon Revision 2.1.1, 2.2 (SWPU064)
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* - OMAP2430 Multimedia Device POP Silicon Revision 2.1 (SWPU090)
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* - OMAP34xx Multimedia Device Silicon Revision 3.1 (SWPU108)
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* - OMAP4430 Multimedia Device Silicon Revision 1.0 (SWPU140)
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* - Open Core Protocol Specification 2.2
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* Copious documentation and references can also be found in the
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* omap_hwmod code, in arch/arm/mach-omap2/omap_hwmod.c (as of this
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* writing).
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*
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* To do:
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* - add interconnect error log structures
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* - add pinmuxing
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* - init_conn_id_bit (CONNID_BIT_VECTOR)
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* - implement default hwmod SMS/SDRC flags?
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* - remove unused fields
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*
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*/
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#ifndef __ARCH_ARM_PLAT_OMAP_INCLUDE_MACH_OMAP_HWMOD_H
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