Messages in this thread | | | Date | Tue, 17 Jan 2023 13:34:25 +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 Tue, Jan 17, 2023 at 10:30:26AM +0530, Siddharth Vadapalli wrote: > Roger, Leon, > > On 16/01/23 21:31, Roger Quadros wrote: > > 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: > > I realized that the cases I mentioned are not explained clearly. Therefore, I > will mention the cases again, along with the section of code they correspond to, > in order to make it clear. > > Case-1: am65_cpsw_init_cpts() returns 0 since CONFIG_TI_K3_AM65_CPTS is not > enabled. This corresponds to the following section within am65_cpsw_init_cpts(): > > if (!IS_ENABLED(CONFIG_TI_K3_AM65_CPTS)) > return 0; > > In this case, common->cpts remains NULL, but it is not a problem even if the > am65_cpsw_nuss_probe() fails later, since the am65_cpts_release() function is > NOP. Thus, this case is not an issue. > > Case-2: am65_cpsw_init_cpts() returns -ENOENT since the cpts node is not present > in the device tree. This corresponds to the following section within > am65_cpsw_init_cpts(): > > node = of_get_child_by_name(dev->of_node, "cpts"); > if (!node) { > dev_err(dev, "%s cpts not found\n", __func__); > return -ENOENT; > } > > In this case as well, common->cpts remains NULL, but it is not a problem because > the probe fails and the execution jumps to "err_of_clear", which doesn't invoke > am65_cpsw_cpts_cleanup(). Therefore, common->cpts being NULL is not a problem. > > Case-3 and Case-4 are described later in this mail. > > >> 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. > > Yes Roger, thank you for pointing it out. When I wrote "cpts is disabled", I had > meant that the following section is executed within the am65_cpsw_init_cpts() > function: > > Case-3: > > cpts = am65_cpts_create(dev, reg_base, node); > if (IS_ERR(cpts)) { > int ret = PTR_ERR(cpts); > > of_node_put(node); > if (ret == -EOPNOTSUPP) { > dev_info(dev, "cpts disabled\n"); > return 0; > }
This code block is unreachable, because of config earlier. 1916 static int am65_cpsw_init_cpts(struct am65_cpsw_common *common) 1917 { ... 1923 if (!IS_ENABLED(CONFIG_TI_K3_AM65_CPTS)) 1924 return 0; ... 1933 cpts = am65_cpts_create(dev, reg_base, node); 1934 if (IS_ERR(cpts)) { 1935 int ret = PTR_ERR(cpts); 1936 1937 of_node_put(node); 1938 if (ret == -EOPNOTSUPP) { 1939 dev_info(dev, "cpts disabled\n"); 1940 return 0; 1941 }
You should delete all the logic above.
Thanks
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