From: Paul Walmsley Date: Tue, 14 Dec 2010 19:42:35 +0000 (-0700) Subject: OMAP2+: hwmod: upgrade per-hwmod mutex to a spinlock X-Git-Tag: v2.6.38-rc1~469^2~15^2~67 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dc6d1cda044b24c3d9f8e4af0431887ebe3488ef;p=pandora-kernel.git OMAP2+: hwmod: upgrade per-hwmod mutex to a spinlock Change the per-hwmod mutex to a spinlock. (The per-hwmod lock serializes most post-initialization hwmod operations such as enable, idle, and shutdown.) Spinlocks are needed, because in some cases, hwmods must be enabled from timer interrupt disabled-context, such as an ISR. The current use-case that is driving this is the OMAP GPIO block ISR: it can trigger interrupts even with its clocks disabled, but these clocks are needed for register accesses in the ISR to succeed. This patch also effectively reverts commit 848240223c35fcc71c424ad51a8e8aef42d3879c - this patch makes _omap_hwmod_enable() and _omap_hwmod_init() static, renames them back to _enable() and _idle(), and changes their callers to call the spinlocking versions. Previously, since omap_hwmod_{enable,init}() attempted to take mutexes, these functions could not be called while the timer interrupt was disabled; but now that the functions use spinlocks and save and restore the IRQ state, it is appropriate to call them directly. Kevin Hilman originally proposed this patch - thanks Kevin. Signed-off-by: Paul Walmsley Cc: Kevin Hilman Cc: Benoît Cousson --- Reading git-diff-tree failed