In order to review Maulik's latest "rpmh_flush for non OSI targets" patch series I've found myself trying to understand rpmh-rsc better. To make it easier for others to do this in the future, add a whole lot of comments / documentation. As part of this there are a very small number of functional changes. - We'll get a tiny performance boost by getting rid of the "cmd_cache" which I believe was unnecessary. - We now assume someone else is in charge of exclusivity for tcs_invalidate() and have removed a lock in there. As per the comments in the patch, this isn't expected to cause problems. - tcs_is_free() no longer checks hardware state, but we think it didn't need to. These changes touch a lot of code in rpmh-rsc, so hopefully someone at Qualcomm can test them out better than I did (I don't have every last client of RPMH in my tree). I've tried to structure the patches so that simpler / less controversial patches are first. Those could certainly land on their own without later patches. Many of the patches could also be dropped and the others would still apply if they are controversial. If you need help doing this then please yell. These patches are based on Maulik's v16 series, AKA: https://lore.kernel.org/r/1586154741-8293-1-git-send-email-mkshah@xxxxxxxxxxxxxx/ With all that, enjoy. Changes in v3: - ("...are not for IRQ") is new for v3. - ("Don't double-check rpmh") replaces ("Warning if tcs_write...") - Add "TCS" in title (Maulik). - Adjusted comments for rpmh_rsc_write_ctrl_data(). - Comments for new enable_tcs_irq() function. - Comments for new rpmh_rsc_cpu_pm_callback() function. - Extra blank line removed (Maulik). - IRQ registers aren't in TCS0 (Maulik). - Kill find_match moves from patch #9 to patch #5 (Maulik). - Mention in message that I also fixed up kernel-doc stuff. - Moved comments patch after ("Kill cmd_cache and find_match..."). - One space after a period now (Maulik). - Plural of TCS fixed to TCSes following Maulik's example. - Re-added comment in tcs_write() about checking for same address. - Rebased atop v16 ('Invoke rpmh_flush...') series. - Replace ("...warn if state mismatch") w/ ("...just check tcs_in_use") - Replaced ("irqsave()...") + ("...never -EBUSY") w/ ("Caller handles...") - Rewrote commit message to adjust for patch order. - __tcs_set_trigger() comments adjusted now that it can set or unset. - get_tcs_for_msg() documents why it's safe to borrow the wake TCS. - get_tcs_for_msg() no longer returns -EAGAIN. Changes in v2: - Comment tcs_is_free() new for v2; replaces old patch 6. - Document bug of tcs_write() not handling -EAGAIN. - Document get_tcs_for_msg() => -EAGAIN only for ACTIVE_ONLY. - Document locks for updating "tcs_in_use" more. - Document tcs_is_free() without drv->lock OK for tcs_invalidate(). - Document that rpmh_rsc_send_data() can be an implicit invalidate. - Document two get_tcs_for_msg() issues if zero-active TCS. - Fixed documentation of "tcs" param in find_slots(). - Got rid of useless "if (x) continue" at end of for loop. - More clear that active-only xfers can happen on wake TCS sometimes. - Now prose in comments instead of struct definitions. - Pretty ASCII art from Stephen. - Reword tcs_write() doc a bit. Douglas Anderson (10): drivers: qcom: rpmh-rsc: Clean code reading/writing TCS regs/cmds drivers: qcom: rpmh-rsc: Document the register layout better drivers: qcom: rpmh-rsc: Fold tcs_ctrl_write() into its single caller drivers: qcom: rpmh-rsc: Remove get_tcs_of_type() abstraction drivers: qcom: rpmh-rsc: Kill cmd_cache and find_match() with fire drivers: qcom: rpmh-rsc: A lot of comments drivers: qcom: rpmh-rsc: tcs_is_free() can just check tcs_in_use drivers: qcom: rpmh-rsc: Don't double-check rpmh drivers: qcom: rpmh-rsc: Caller handles tcs_invalidate() exclusivity drivers: qcom: rpmh-rsc: read_tcs_reg()/write_tcs_reg() are not for IRQ drivers/soc/qcom/rpmh-internal.h | 66 +++-- drivers/soc/qcom/rpmh-rsc.c | 465 +++++++++++++++++++++---------- drivers/soc/qcom/rpmh.c | 5 +- 3 files changed, 363 insertions(+), 173 deletions(-) -- 2.26.0.292.g33ef6b2f38-goog
