On Tue, Jan 17, 2023 at 05:27:46PM +0800, Edward Chow wrote: > Loading calibration data from an OF device tree node not declared > compatible with the device (e.g. a PCI device with calibration data > from corresponding DT node gets replaced, so the newly installed > device become incompatible with the node) or driver may lead to fatal > result, e.g. kernel panic. Please include a link to a bug report and include a few lines of the oops or panic directly in the commit log so when users see this problem, they can search for the text and possibly find this fix. > The driver should check whether the DT node corresponding to the > device compatible with it, and load calibration data only from > compatible node. If you read this commit log carefully, it doesn't actually say what this patch *does*. It has some background and this assertion about what drivers *should* do, but it doesn't say what this patch does. Suggest structure like this (flesh out with the relevant DT property names, etc): For PCI ath9k devices, load calibration data only if there is a DT node corresponding to the device with XXX ... More details: https://chris.beams.io/posts/git-commit/ > Signed-off-by: Edward Chow <equu@xxxxxxxxxxx> > --- > drivers/net/wireless/ath/ath9k/ath9k.h | 1 + > drivers/net/wireless/ath/ath9k/init.c | 26 ++++++++++++++++++++++++++ > drivers/net/wireless/ath/ath9k/pci.c | 2 +- > 3 files changed, 28 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h > index 2cc23605c9fc..4f6f0383a5f8 100644 > --- a/drivers/net/wireless/ath/ath9k/ath9k.h > +++ b/drivers/net/wireless/ath/ath9k/ath9k.h > @@ -35,6 +35,7 @@ struct ath_node; > struct ath_vif; > > extern struct ieee80211_ops ath9k_ops; > +extern struct pci_driver ath_pci_driver; > extern int ath9k_modparam_nohwcrypt; > extern int ath9k_led_blink; > extern bool is_ath9k_unloaded; > diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c > index 4f00400c7ffb..f88a48e8456b 100644 > --- a/drivers/net/wireless/ath/ath9k/init.c > +++ b/drivers/net/wireless/ath/ath9k/init.c > @@ -22,6 +22,7 @@ > #include <linux/module.h> > #include <linux/of.h> > #include <linux/of_net.h> > +#include <linux/pci.h> > #include <linux/nvmem-consumer.h> > #include <linux/relay.h> > #include <linux/dmi.h> > @@ -577,6 +578,31 @@ static int ath9k_nvmem_request_eeprom(struct ath_softc *sc) > size_t len; > int err; > > + /* devm_nvmem_cell_get() will get a cell first from the OF > + * DT node representing the given device with nvmem-cell-name > + * "calibration", and from the global lookup table as a fallback, > + * and an ath9k device could be either a pci one or a platform one. > + * > + * If the OF DT node is not compatible with the real device, the > + * calibration data got from the node should not be applied. > + * > + * dev_is_pci(sc->dev) && ( no OF node || caldata not from node > + * || not compatible ) -> do not use caldata . > + * > + * !dev_is_pci(sc->dev) -> always use caldata . > + */ > + if (dev_is_pci(sc->dev) && > + (!sc->dev->of_node || > + !of_property_match_string(sc->dev->of_node, > + "nvmem-cell-names", > + "calibration") || > + !of_pci_node_match_driver(sc->dev->of_node, > + &ath_pci_driver))) > + /* follow the "just return 0;" convention as > + * noted below. > + */ > + return 0; > + > cell = devm_nvmem_cell_get(sc->dev, "calibration"); > if (IS_ERR(cell)) { > err = PTR_ERR(cell); > diff --git a/drivers/net/wireless/ath/ath9k/pci.c b/drivers/net/wireless/ath/ath9k/pci.c > index a074e23013c5..fcb19761e60d 100644 > --- a/drivers/net/wireless/ath/ath9k/pci.c > +++ b/drivers/net/wireless/ath/ath9k/pci.c > @@ -1074,7 +1074,7 @@ static SIMPLE_DEV_PM_OPS(ath9k_pm_ops, ath_pci_suspend, ath_pci_resume); > > MODULE_DEVICE_TABLE(pci, ath_pci_id_table); > > -static struct pci_driver ath_pci_driver = { > +struct pci_driver ath_pci_driver = { > .name = "ath9k", > .id_table = ath_pci_id_table, > .probe = ath_pci_probe, > -- > 2.39.0 >
