3c82e229f0
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.html Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Jarkko Nikula <jhnikula@gmail.com> |
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