mbox series

[v7,0/3] PCI: brcmstb: Configure appropriate HW CLKREQ# mode

Message ID 20231109191355.27738-1-james.quinlan@broadcom.com
Headers show
Series PCI: brcmstb: Configure appropriate HW CLKREQ# mode | expand

Message

Jim Quinlan Nov. 9, 2023, 7:13 p.m. UTC
v7 -- Manivannan Sadhasivam suggested (a) making the property look like a
      network phy-mode and (b) keeping the code simple (not counting clkreq
      signal appearances, un-advertising capabilites, etc).  This is
      what I have done.  The property is now "brcm,clkreq-mode" and
      the values may be one of "safe", "default", and "no-l1ss".  The
      default setting is to employ the most capable power savings mode.

v6 -- No code has been changed.
   -- Changed commit subject and comment in "#PERST" commit (Bjorn, Cyril)
   -- Changed sign-off and author email address for all commits.
      This was due to a change in Broadcom's upstreaming policy.

v5 -- Remove DT property "brcm,completion-timeout-us" from	 
      "DT bindings" commit.  Although this error may be reported	 
      as a completion timeout, its cause was traced to an	 
      internal bus timeout which may occur even when there is	 
      no PCIe access being processed.  We set a timeout of four	 
      seconds only if we are operating in "L1SS CLKREQ#" mode.
   -- Correct CEM 2.0 reference provided by HW engineer,
      s/3.2.5.2.5/3.2.5.2.2/ (Bjorn)
   -- Add newline to dev_info() string (Stefan)
   -- Change variable rval to unsigned (Stefan)
   -- s/implementaion/implementation/ (Bjorn)
   -- s/superpowersave/powersupersave/ (Bjorn)
   -- Slightly modify message on "PERST#" commit.
   -- Rebase to torvalds master

v4 -- New commit that asserts PERST# for 2711/RPi SOCs at PCIe RC
      driver probe() time.  This is done in Raspian Linux and its
      absence may be the cause of a failing test case.
   -- New commit that removes stale comment.

v3 -- Rewrote commit msgs and comments refering panics if L1SS
      is enabled/disabled; the code snippet that unadvertises L1SS
      eliminates the panic scenario. (Bjorn)
   -- Add reference for "400ns of CLKREQ# assertion" blurb (Bjorn)
   -- Put binding names in DT commit Subject (Bjorn)
   -- Add a verb to a commit's subject line (Bjorn)
   -- s/accomodat(\w+)/accommodat$1/g (Bjorn)
   -- Rewrote commit msgs and comments refering panics if L1SS
      is enabled/disabled; the code snippet that unadvertises L1SS
      eliminates the panic scenario. (Bjorn)

v2 -- Changed binding property 'brcm,completion-timeout-msec' to
      'brcm,completion-timeout-us'.  (StefanW for standard suffix).
   -- Warn when clamping timeout value, and include clamped
      region in message. Also add min and max in YAML. (StefanW)
   -- Qualify description of "brcm,completion-timeout-us" so that
      it refers to PCIe transactions. (StefanW)
   -- Remvove mention of Linux specifics in binding description. (StefanW)
   -- s/clkreq#/CLKREQ#/g (Bjorn)
   -- Refactor completion-timeout-us code to compare max and min to
      value given by the property (as opposed to the computed value).

v1 -- The current driver assumes the downstream devices can
      provide CLKREQ# for ASPM.  These commits accomodate devices
      w/ or w/o clkreq# and also handle L1SS-capable devices.

   -- The Raspian Linux folks have already been using a PCIe RC
      property "brcm,enable-l1ss".  These commits use the same
      property, in a backward-compatible manner, and the implementaion
      adds more detail and also automatically identifies devices w/o
      a clkreq# signal, i.e. most devices plugged into an RPi CM4
      IO board.


Jim Quinlan (3):
  dt-bindings: PCI: brcmstb: Add property "brcm,clkreq-mode"
  PCI: brcmstb: Configure HW CLKREQ# mode appropriate for downstream
    device
  PCI: brcmstb: Set higher value for internal bus timeout

 .../bindings/pci/brcm,stb-pcie.yaml           | 21 +++++
 drivers/pci/controller/pcie-brcmstb.c         | 81 ++++++++++++++++---
 2 files changed, 92 insertions(+), 10 deletions(-)


base-commit: 305230142ae0637213bf6e04f6d9f10bbcb74af8

Comments

Florian Fainelli Nov. 13, 2023, 5:36 p.m. UTC | #1
On 11/9/23 11:13, Jim Quinlan wrote:
> v7 -- Manivannan Sadhasivam suggested (a) making the property look like a
>        network phy-mode and (b) keeping the code simple (not counting clkreq
>        signal appearances, un-advertising capabilites, etc).  This is
>        what I have done.  The property is now "brcm,clkreq-mode" and
>        the values may be one of "safe", "default", and "no-l1ss".  The
>        default setting is to employ the most capable power savings mode.
> 
> v6 -- No code has been changed.
>     -- Changed commit subject and comment in "#PERST" commit (Bjorn, Cyril)
>     -- Changed sign-off and author email address for all commits.
>        This was due to a change in Broadcom's upstreaming policy.
> 
> v5 -- Remove DT property "brcm,completion-timeout-us" from	
>        "DT bindings" commit.  Although this error may be reported	
>        as a completion timeout, its cause was traced to an	
>        internal bus timeout which may occur even when there is	
>        no PCIe access being processed.  We set a timeout of four	
>        seconds only if we are operating in "L1SS CLKREQ#" mode.
>     -- Correct CEM 2.0 reference provided by HW engineer,
>        s/3.2.5.2.5/3.2.5.2.2/ (Bjorn)
>     -- Add newline to dev_info() string (Stefan)
>     -- Change variable rval to unsigned (Stefan)
>     -- s/implementaion/implementation/ (Bjorn)
>     -- s/superpowersave/powersupersave/ (Bjorn)
>     -- Slightly modify message on "PERST#" commit.
>     -- Rebase to torvalds master
> 
> v4 -- New commit that asserts PERST# for 2711/RPi SOCs at PCIe RC
>        driver probe() time.  This is done in Raspian Linux and its
>        absence may be the cause of a failing test case.
>     -- New commit that removes stale comment.
> 
> v3 -- Rewrote commit msgs and comments refering panics if L1SS
>        is enabled/disabled; the code snippet that unadvertises L1SS
>        eliminates the panic scenario. (Bjorn)
>     -- Add reference for "400ns of CLKREQ# assertion" blurb (Bjorn)
>     -- Put binding names in DT commit Subject (Bjorn)
>     -- Add a verb to a commit's subject line (Bjorn)
>     -- s/accomodat(\w+)/accommodat$1/g (Bjorn)
>     -- Rewrote commit msgs and comments refering panics if L1SS
>        is enabled/disabled; the code snippet that unadvertises L1SS
>        eliminates the panic scenario. (Bjorn)
> 
> v2 -- Changed binding property 'brcm,completion-timeout-msec' to
>        'brcm,completion-timeout-us'.  (StefanW for standard suffix).
>     -- Warn when clamping timeout value, and include clamped
>        region in message. Also add min and max in YAML. (StefanW)
>     -- Qualify description of "brcm,completion-timeout-us" so that
>        it refers to PCIe transactions. (StefanW)
>     -- Remvove mention of Linux specifics in binding description. (StefanW)
>     -- s/clkreq#/CLKREQ#/g (Bjorn)
>     -- Refactor completion-timeout-us code to compare max and min to
>        value given by the property (as opposed to the computed value).
> 
> v1 -- The current driver assumes the downstream devices can
>        provide CLKREQ# for ASPM.  These commits accomodate devices
>        w/ or w/o clkreq# and also handle L1SS-capable devices.
> 
>     -- The Raspian Linux folks have already been using a PCIe RC
>        property "brcm,enable-l1ss".  These commits use the same
>        property, in a backward-compatible manner, and the implementaion
>        adds more detail and also automatically identifies devices w/o
>        a clkreq# signal, i.e. most devices plugged into an RPi CM4
>        IO board.

For the entire series:

Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>

on all of my available devices:

- SUNIX Co., Ltd. Multiport serial controller
- Broadcom BCM4331 Wi-Fi
- Broadcom BCM43224 Wi-Fi
- Broadcom BCM4322 Wi-Fi
- Qualcomm Atheros AR5008
- Broadcom BCM4366 Wi-Fi
- Marvell Technology Group Ltd. 88SE9125 PCIe SATA 6.0 Gb/s controller
- Intel 7260 Wi-Fi
- Intel Corporation 82574L Gigabit Network Connection
- Broadcom NetXtreme BCM5751 Gigabit Ethernet
- Pepperl+Fuchs RocketPort EXPRESS 8-port w/Octa Cable
- Micron/Crucial Technology P2 NVMe PCIe SSD
- ASM1184e PCIe Switch Port