On Mon, Jul 12, 2021 at 1:53 AM Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> wrote: > > On Thu, Jul 01, 2021 at 09:25:01AM -0600, Rob Herring wrote: > > On Tue, Jun 29, 2021 at 9:47 PM Manivannan Sadhasivam > > <manivannan.sadhasivam@xxxxxxxxxx> wrote: > > > > > > Hello, > > > > > > This series adds support for Qualcomm PCIe Endpoint controller found > > > in platforms like SDX55. The Endpoint controller is based on the designware > > > core with additional Qualcomm wrappers around the core. > > > > > > The driver is added separately unlike other Designware based drivers that > > > combine RC and EP in a single driver. This is done to avoid complexity and > > > to maintain this driver autonomously. > > > > > > The driver has been validated with an out of tree MHI function driver on > > > SDX55 based Telit FN980 EVB connected to x86 host machine over PCIe. > > > > > > Thanks, > > > Mani > > > > > > Changes in v5: > > > > > > * Removed the DBI register settings that are not needed > > > * Used the standard definitions available in pci_regs.h > > > * Added defines for all the register fields > > > * Removed the left over code from previous iteration > > > > > > Changes in v4: > > > > > > * Removed the active_config settings needed for IPA integration > > > * Switched to writel for couple of relaxed versions that sneaked in > > > > I thought we resolved this discussion. Use _relaxed variants unless > > you need the stronger ones. > > > > I thought the discussion was resolved in favor of using read/writel. Here > is the last reply from Bjorn: > > "I think we came to the conclusion that writel() was better > than incorrect use of writel_relaxed() followed by wmb(). And in this > particular case it's definitely not happening in a hot code path..." Certainly if you're needing wmb(), then you shouldn't be using _relaxed() variants. > IMO, it is safer to use readl/writel calls than the relaxed variants. Sure, and it's safer to have one big lock than it is to have no locks or lots of small locks. > And so far the un-written rule I assumed is, only consider using the > relaxed variants if the code is in hot path (but somehow I used the > relaxed version in v1 :P ) If you want any real conclusion, then best to fix the 'un-written' part. But what I say for every PCI review, is use the _relaxed() variants. Rob
