Messages in this thread | | | Date | Mon, 16 Jan 2023 18:01:40 +0200 | Subject | Re: [PATCH net-next v2] net: ethernet: ti: am65-cpsw/cpts: Fix CPTS release action | From | Roger Quadros <> |
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Hi Siddharth,
On 16/01/2023 09:43, 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. > 2. am65_cpsw_init_cpts() returns -ENOENT since the cpts node is not defined. > 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.
In this case common->cpts is not NULL and is set to error pointer. Probe will continue normally. Is it OK to call any of the cpts APIs with invalid handle? Also am65_cpts_release() will be called with invalid handle.
> 4. The call to am65_cpts_create() within the am65_cpsw_init_cpts() function > fails with an error.
In this case common->cpts is not NULL and will invoke am65_cpts_release() with invalid handle.
> > 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. > >> >> And why do you need special am65_cpsw_cpts_cleanup() which does nothing >> except call to am65_cpts_release()? It will be more intuitive change >> the latter to be exported function. > > The am65_cpts_release() function expects the cpts pointer to be valid. Thus, I > had added the am65_cpsw_cpts_cleanup() function to conditionally invoke the > am65_cpts_release() function whenever the cpts pointer is valid. Based on your > suggestion, I believe that you want me to check for the cpts pointer being valid > within the am65_cpts_release() function instead, so that the > am65_cpsw_cpts_cleanup() function doesn't have to be added. Please let me know > if this is what you meant. > > Regards, > Siddharth.
cheers, -roger
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