Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 16 Jan 2023 13:26:31 +0200 | From | Leon Romanovsky <> | Subject | Re: [PATCH net-next v2] net: ethernet: ti: am65-cpsw/cpts: Fix CPTS release action |
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On Mon, Jan 16, 2023 at 04:07:16PM +0530, Siddharth Vadapalli wrote: > > > On 16/01/23 15:34, Leon Romanovsky wrote: > > On Mon, Jan 16, 2023 at 01:13:36PM +0530, Siddharth Vadapalli wrote: > >> > >> > >> On 16/01/23 13:00, Leon Romanovsky wrote: > >>> On Mon, Jan 16, 2023 at 10:15:17AM +0530, Siddharth Vadapalli wrote: > >>>> The am65_cpts_release() function is registered as a devm_action in the > >>>> am65_cpts_create() function in am65-cpts driver. When the am65-cpsw driver > >>>> invokes am65_cpts_create(), am65_cpts_release() is added in the set of devm > >>>> actions associated with the am65-cpsw driver's device. > >>>> > >>>> In the event of probe failure or probe deferral, the platform_drv_probe() > >>>> function invokes dev_pm_domain_detach() which powers off the CPSW and the > >>>> CPSW's CPTS hardware, both of which share the same power domain. Since the > >>>> am65_cpts_disable() function invoked by the am65_cpts_release() function > >>>> attempts to reset the CPTS hardware by writing to its registers, the CPTS > >>>> hardware is assumed to be powered on at this point. However, the hardware > >>>> is powered off before the devm actions are executed. > >>>> > >>>> Fix this by getting rid of the devm action for am65_cpts_release() and > >>>> invoking it directly on the cleanup and exit paths. > >>>> > >>>> Fixes: f6bd59526ca5 ("net: ethernet: ti: introduce am654 common platform time sync driver") > >>>> Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com> > >>>> Reviewed-by: Roger Quadros <rogerq@kernel.org> > >>>> --- > >>>> Changes from v1: > >>>> 1. Fix the build issue when "CONFIG_TI_K3_AM65_CPTS" is not set. This > >>>> error was reported by kernel test robot <lkp@intel.com> at: > >>>> https://lore.kernel.org/r/202301142105.lt733Lt3-lkp@intel.com/ > >>>> 2. Collect Reviewed-by tag from Roger Quadros. > >>>> > >>>> v1: > >>>> https://lore.kernel.org/r/20230113104816.132815-1-s-vadapalli@ti.com/ > >>>> > >>>> drivers/net/ethernet/ti/am65-cpsw-nuss.c | 8 ++++++++ > >>>> drivers/net/ethernet/ti/am65-cpts.c | 15 +++++---------- > >>>> drivers/net/ethernet/ti/am65-cpts.h | 5 +++++ > >>>> 3 files changed, 18 insertions(+), 10 deletions(-) > >>>> > >>>> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c > >>>> index 5cac98284184..00f25d8a026b 100644 > >>>> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c > >>>> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c > >>>> @@ -1913,6 +1913,12 @@ static int am65_cpsw_am654_get_efuse_macid(struct device_node *of_node, > >>>> return 0; > >>>> } > >>>> > >>>> +static void am65_cpsw_cpts_cleanup(struct am65_cpsw_common *common) > >>>> +{ > >>>> + if (IS_ENABLED(CONFIG_TI_K3_AM65_CPTS) && common->cpts) > >>> > >>> Why do you have IS_ENABLED(CONFIG_TI_K3_AM65_CPTS), if > >>> am65_cpts_release() defined as empty when CONFIG_TI_K3_AM65_CPTS not set? > >>> > >>> How is it possible to have common->cpts == NULL? > >> > >> Thank you for reviewing the patch. I realize now that checking > >> CONFIG_TI_K3_AM65_CPTS is unnecessary. > >> > >> common->cpts remains NULL in the following cases: > >> 1. am65_cpsw_init_cpts() returns 0 since CONFIG_TI_K3_AM65_CPTS is not enabled. > > > > In this case am65_cpsw_cpts_cleanup() will NOP as well. > > > >> 2. am65_cpsw_init_cpts() returns -ENOENT since the cpts node is not defined. > > > > It is an error and all callers unwind properly. > > > >> 3. The call to am65_cpts_create() fails within the am65_cpsw_init_cpts() > >> function with a return value of 0 when cpts is disabled. > > > > It is disabled by CONFIG_TI_K3_AM65_CPTS, which in turn will make > > am65_cpsw_cpts_cleanup() NOP. > > > >> 4. The call to am65_cpts_create() within the am65_cpsw_init_cpts() function > >> fails with an error. > >> > >> Of the above cases, the am65_cpsw_cpts_cleanup() function would have to handle > >> cases 1 and 3, since the probe might fail at a later point, following which the > >> probe cleanup path will invoke the am65_cpts_cpts_cleanup() function. This > >> function then checks for common->cpts not being NULL, so that it can invoke the > >> am65_cpts_release() function with this pointer. > > > > I still don't see how it is possible. > > You are right! I apologize for not analyzing the cases well enough. The only > case where common->cpts will remain NULL and the am65_cpsw_cpts_cleanup() > function is invoked, is the case where the CONFIG_TI_K3_AM65_CPTS config is > disabled. As you had pointed it out, in this case, the am65_cpts_release() is > NOP, so passing the NULL pointer common->cpts will have no effect. > > With this, I understand that the am65_cpsw_cpts_cleanup() function is > unnecessary like you had mentioned, and am65_cpts_release() can be directly > invoked for common->cpts. Please let me know if my understanding is correct. If > so, I will implement this in the v3 patch.
Yes, you understood me right.
Thanks
> > Regards, > Siddharth.
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