Re: [PATCH v14 0/17] PCI: imx6: refine codes and add the error propagation

From: Bjorn Helgaas
Date: Mon Jul 11 2022 - 18:30:07 EST

On Fri, Jul 01, 2022 at 11:25:18AM +0800, Richard Zhu wrote:
> This series patches refine pci-imx6 driver and do the following main changes.
> - Encapsulate the clock enable into one standalone function
> - Add the error propagation from host_init and resume
> - Turn off regulator when the system is in suspend mode
> - Let the probe successfully when link never comes up
> - Do not hide the phy driver callbacks in core reset and clk_enable.
> - Keep symmetric as much as possible between suspend and resume callbacks.
> BTW, this series are verified on i.MX8MM EVK board when one NVME is used.
> Main changes from v13 to v14 refer to Bjorn's comments:
> - To keep suspend/resume symmetric as much as possible. Create
> imx6_pcie_stop_link() and imx6_pcie_host_exit() functions, and invoke
> them in suspend callback.
> - Since the imx6_pcie_clk_disable() is invoked by imx6_pcie_host_exit(),
> to be symmetric with imx6_pcie_host_exit(), move imx6_pcie_clk_enable()
> to imx6_pcie_host_init() from imx6_pcie_deassert_core_reset().
> Main changes from v12 to v13:
> - Call imx6_pcie_host_init() instead of duplicating codes in resume.
> - Move the regulator enable out of imx6_pcie_deassert_core_reset().
> Re-format the error handling in imx6_pcie_deassert_core_reset()
> and imx6_pcie_host_init() accordingly.
> Main changes from v11 to v12 issued by Bjorn:
> - Add four intro patches to move code around to collect similar things
> (PHY management, reset management) together. This makes the first
> diff to collect clock enables simpler because it's not cluttered with
> unrelated things that didn't actually change.
> - Factor out ref clock disables so the disable function structure matches
> the enable structure.
> - Drop unused "ret" from "Reduce resume time ..." to avoid bisection
> hole, then add it back in "Do not hide phy driver ..." where we start
> using it again.
> - Add patch to make imx6_pcie_clk_disable() symmetric with
> imx6_pcie_clk_enable() in terms of enable/disable ordering.
> Main changes from v10 to v11:
> No code changes, just do the following operations refer to Bjorn's comments.
> - Split #6 patch into two patches.
> - Rebase to v5.19-rc1 based on for-next branch of Shawn's git.
> Main changes from v9 to v10:
> - Add the "Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>" tag into #3
> and #4 patches.
> - Refer to Bjorn's comments:
> - refine the commit of the first patch
> - keep alignment of the message format in the second patch
> - More specific commit and subject of the #5 and #7 patches.
> - Move the regualtor_disable into suspend, turn off the regulator when bus
> is powered off and system in suspend mode.
> - Let the driver probe successfully, return zero in imx6_pcie_start_link()
> when PCIe link is down.
> In this link down scenario, only start the PCIe link training in resume
> when the link is up before system suspend to avoid the long latency in
> the link training period.
> - Don't hide phy driver callbacks in core reset and clk_enable, and refine
> the error handling accordingly.
> - Drop the #8 patch of v9 series, since the clocks and powers are not gated
> off anymore when link is down.
> Main changes from v8 to v9:
> - Don't change pcie-designware codes, and do the error exit process only in
> pci-imx6 driver internally.
> - Move the phy driver callbacks to the proper places
> Main changes from v7 to v8:
> Regarding Bjorn's review comments.
> - Align the format of the dev_info message and refine commit log of
> #6/7/8 patches.
> - Rename the err_reset_phy label, since there is no PHY reset in the out
> Main changes from v6 to v7:
> - Keep the regulator usage counter balance in the #5 patch of v6 series.
> Main changes from v5 to v6:
> - Refer to the following discussion with Fabio, fix the dump by his patch.
> Refine and rebase this patch-set after Fabio' dump fix patch is merged.
> - Add one new #4 patch to disable i.MX6QDL REF clock too when disable clocks
> - Split the regulator refine codes into one standalone patch #5 in this version.
> Main changes from v4 to v5:
> - Since i.MX8MM PCIe support had been merged. Based on Lorenzo's git repos,
> resend the patch-set after rebase.
> Main changes from v3 to v4:
> - Regarding Mark's comments, delete the regulator_is_enabled() check.
> - Squash #3 and #6 of v3 patch into #5 patch of v4 set.
> Main changes from v2 to v3:
> - Add "Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>" tag into
> first two patches.
> - Add a Fixes tag into #3 patch.
> - Split the #4 of v2 to two patches, one is clock disable codes move,
> the other one is the acutal clock unbalance fix.
> - Add a new host_exit() callback into dw_pcie_host_ops, then it could be
> invoked to handle the unbalance issue in the error handling after
> host_init() function when link is down.
> - Add a new host_exit() callback for i.MX PCIe driver to handle this case
> in the error handling after host_init.
> Main changes from v1 to v2:
> Regarding Lucas' comments.
> - Move the placement of the new imx6_pcie_clk_enable() to avoid the
> forward declarition.
> - Seperate the second patch of v1 patch-set to three patches.
> - Use the module_param to replace the kernel command line.
> Regarding Bjorn's comments:
> - Use the cover-letter for a multi-patch series.
> - Correct the subject line, and refine the commit logs. For example,
> remove the timestamp of the logs.
> Bjorn Helgaas (5):
> PCI: imx6: Move imx6_pcie_grp_offset(), imx6_pcie_configure_type()
> earlier
> PCI: imx6: Move PHY management functions together
> PCI: imx6: Move imx6_pcie_enable_ref_clk() earlier
> PCI: imx6: Factor out ref clock disable to match enable
> PCI: imx6: Disable clocks in reverse order of enable
> Richard Zhu (12):
> PCI: imx6: Move imx6_pcie_clk_disable() earlier
> PCI: imx6: Collect clock enables in imx6_pcie_clk_enable()
> PCI: imx6: Propagate .host_init() errors to caller
> PCI: imx6: Disable i.MX6QDL clock when disabling ref clocks
> PCI: imx6: Call host init function directly in resume
> PCI: imx6: Turn off regulator when system is in suspend mode
> PCI: imx6: Move regulator enable out of
> imx6_pcie_deassert_core_reset()
> PCI: imx6: Mark the link down as non-fatal error
> PCI: imx6: Reduce resume time by only starting link if it was up
> before suspend
> PCI: imx6: Do not hide phy driver callbacks and refine the error
> handling
> PCI: imx6: Reformat suspend callback to keep symmetric with resume
> PCI: imx6: Move the imx6_pcie_ltssm_disable() earlier
> drivers/pci/controller/dwc/pci-imx6.c | 661 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----------------------------------------------------------------------------------------------
> 1 file changed, 358 insertions(+), 303 deletions(-)

Applied to pci/ctrl/imx6 for v5.20, thanks a lot for all your work