[V2,1/2] PCI/ASPM: Add ASPM BIOS override function

Commit Message

David E. Box Dec. 7, 2021, 10:30 p.m. UTC

From: Michael Bottini <[e-mail]>

Devices that appear under the Intel VMD host bridge are not visible to BIOS
and therefore not programmed by BIOS with ASPM settings. For these devices,
it is necessary for the driver to configure ASPM. Since ASPM settings are
adjustable at runtime by module parameter, use the same mechanism to allow
drivers to override the default (in this case never configured) BIOS policy
to ASPM_STATE_ALL. Then, reconfigure ASPM on the link. Do not override if
ASPM control is disabled.

Signed-off-by: Michael Bottini <[e-mail]>
Signed-off-by: David E. Box <[e-mail]>
---
V2
 - Change return type to int so caller can determine if override was
   successful
 - Return immediately if link is not found so that lock it not
   unecessarily taken, suggested by [e-mail]
 - Don't override if aspm_disabled is true

 drivers/pci/pci.h       |  2 ++
 drivers/pci/pcie/aspm.c | 19 +++++++++++++++++++
 2 files changed, 21 insertions(+)

Comments

kernel test robot Dec. 8, 2021, 12:51 a.m. UTC | #1

Hi "David,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on v5.16-rc4]
[also build test ERROR on next-20211207]
[cannot apply to helgaas-pci/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/David-E-Box/PCI-ASPM-Add-ASPM-BIOS-override-function/20211208-063240
base:    0fcfb00b28c0b7884635dacf38e46d60bf3d4eb1
config: nds32-defconfig (https://download.01.org/0day-ci/archive/20211208/[e-mail]/config)
compiler: nds32le-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/efd5524bd4005ec84d4eb6681c54d1ba93fe9ca1
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review David-E-Box/PCI-ASPM-Add-ASPM-BIOS-override-function/20211208-063240
        git checkout efd5524bd4005ec84d4eb6681c54d1ba93fe9ca1
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=nds32 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[e-mail]>

All errors (new ones prefixed by >>):

   In file included from drivers/pci/of.c:16:
   drivers/pci/pci.h: In function 'pcie_aspm_policy_override':
>> drivers/pci/pci.h:571:83: error: expected ';' before '}' token
     571 | static inline int pcie_aspm_policy_override(struct pci_dev *dev) { return -EINVAL }
         |                                                                                   ^


vim +571 drivers/pci/pci.h

   553	
   554	/* PCI error reporting and recovery */
   555	pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
   556			pci_channel_state_t state,
   557			pci_ers_result_t (*reset_subordinates)(struct pci_dev *pdev));
   558	
   559	bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
   560	#ifdef CONFIG_PCIEASPM
   561	void pcie_aspm_init_link_state(struct pci_dev *pdev);
   562	void pcie_aspm_exit_link_state(struct pci_dev *pdev);
   563	void pcie_aspm_pm_state_change(struct pci_dev *pdev);
   564	void pcie_aspm_powersave_config_link(struct pci_dev *pdev);
   565	int pcie_aspm_policy_override(struct pci_dev *dev);
   566	#else
   567	static inline void pcie_aspm_init_link_state(struct pci_dev *pdev) { }
   568	static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) { }
   569	static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev) { }
   570	static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) { }
 > 571	static inline int pcie_aspm_policy_override(struct pci_dev *dev) { return -EINVAL }
   572	#endif
   573	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[e-mail]

Patch

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 3d60cabde1a1..c741791f15e0 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -562,11 +562,13 @@  void pcie_aspm_init_link_state(struct pci_dev *pdev);
 void pcie_aspm_exit_link_state(struct pci_dev *pdev);
 void pcie_aspm_pm_state_change(struct pci_dev *pdev);
 void pcie_aspm_powersave_config_link(struct pci_dev *pdev);
+int pcie_aspm_policy_override(struct pci_dev *dev);
 #else
 static inline void pcie_aspm_init_link_state(struct pci_dev *pdev) { }
 static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) { }
 static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev) { }
 static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) { }
+static inline int pcie_aspm_policy_override(struct pci_dev *dev) { return -EINVAL }
 #endif
 
 #ifdef CONFIG_PCIE_ECRC
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 52c74682601a..e2c61e14e724 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -1140,6 +1140,25 @@  int pci_disable_link_state(struct pci_dev *pdev, int state)
 }
 EXPORT_SYMBOL(pci_disable_link_state);
 
+int pcie_aspm_policy_override(struct pci_dev *pdev)
+{
+	struct pcie_link_state *link = pcie_aspm_get_link(pdev);
+
+	if (!link || aspm_disabled)
+		return -EINVAL;
+
+	down_read(&pci_bus_sem);
+	mutex_lock(&aspm_lock);
+	link->aspm_default = ASPM_STATE_ALL;
+	pcie_config_aspm_link(link, policy_to_aspm_state(link));
+	pcie_set_clkpm(link, policy_to_clkpm_state(link));
+	mutex_unlock(&aspm_lock);
+	up_read(&pci_bus_sem);
+
+	return 0;
+}
+EXPORT_SYMBOL(pcie_aspm_policy_override);
+
 static int pcie_aspm_set_policy(const char *val,
 				const struct kernel_param *kp)
 {