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Paul Walmsley authored
Fix two bugs in the OMAP3 clock tree pertaining to the SSI, DSS, USBHOST, and HSOTGUSB devices. These devices are both interconnect initiators and targets. Without this patch, clk_enable()s on clocks for these modules can be very high latency (potentially up to ~200 milliseconds) and message such as the following are generated: Clock usbhost_48m_fck didn't enable in 100000 tries Two bugs are fixed by this patch. First, OMAP hardware only supports target CM_IDLEST register bits on ES2+ chips and beyond. ES1 chips should not wait for these clocks to enable. So, split the appropriate clocks into ES1 and ES2+ variants, so that kernels running on ES1 devices won't try to wait. Second, the current heuristic in omap2_clk_dflt_find_idlest() will fail for these clocks. It assumes that the CM_IDLEST bit to wait upon is the same as the CM_*CLKEN bit, which is false[1]. Fix by implementing custom clkops .find_idlest function pointers for the appropriate clocks that return the correct slave IDLEST bit shift. This was originally fixed in the linux-omap kernel during 2.6.29 in a slightly different manner[2][3]. In the medium-term future, all of the module IDLEST code will eventually be moved to the omap_hwmod code. Problem reported by Jarkko Nikula <jhnikula@gmail.com>: http://marc.info/?l=linux-omap&m=124306184903679&w=2 ... 1. See for example 34xx TRM Revision P Table 4-213 and 4-217 (for the DSS case). 2. http://www.spinics.net/lists/linux-omap/msg05512.html et seq. 3. http://lkml.indiana.edu/hypermail/linux/kernel/0901.3/01498.htmlSigned-off-by: Paul Walmsley <paul@pwsan.com> Cc: Jarkko Nikula <jhnikula@gmail.com>
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