Re: [PATCH net-next 4/4] net: stmmac: socfpga: Add hardware supported cross-timestamp

[kernel test robot <lkp@intel.com>]

Hi Rohan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on a8abe8e210c175b1d5a7e53df069e107b65c13cb]

url:    https://github.com/intel-lab-lkp/linux/commits/Rohan-G-Thomas-via-B4-Relay/net-stmmac-socfpga-Agilex5-EMAC-platform-configuration/20251029-162502
base:   a8abe8e210c175b1d5a7e53df069e107b65c13cb
patch link:    https://lore.kernel.org/r/20251029-agilex5_ext-v1-4-1931132d77d6%40altera.com
patch subject: [PATCH net-next 4/4] net: stmmac: socfpga: Add hardware supported cross-timestamp
config: loongarch-allmodconfig (https://download.01.org/0day-ci/archive/20251030/202510301322.f0J41mwI-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251030/202510301322.f0J41mwI-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510301322.f0J41mwI-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c:390:9: warning: variable 'ret' is uninitialized when used here [-Wuninitialized]
     390 |         return ret;
         |                ^~~
   drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c:312:12: note: initialize the variable 'ret' to silence this warning
     312 |         int i, ret;
         |                   ^
         |                    = 0
   1 warning generated.


vim +/ret +390 drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c

   301	
   302	static int smtg_crosststamp(ktime_t *device, struct system_counterval_t *system,
   303				    void *ctx)
   304	{
   305		struct stmmac_priv *priv = (struct stmmac_priv *)ctx;
   306		u32 num_snapshot, gpio_value, acr_value;
   307		void __iomem *ptpaddr = priv->ptpaddr;
   308		void __iomem *ioaddr = priv->hw->pcsr;
   309		unsigned long flags;
   310		u64 smtg_time = 0;
   311		u64 ptp_time = 0;
   312		int i, ret;
   313	
   314		/* Both internal crosstimestamping and external triggered event
   315		 * timestamping cannot be run concurrently.
   316		 */
   317		if (priv->plat->flags & STMMAC_FLAG_EXT_SNAPSHOT_EN)
   318			return -EBUSY;
   319	
   320		mutex_lock(&priv->aux_ts_lock);
   321		/* Enable Internal snapshot trigger */
   322		acr_value = readl(ptpaddr + PTP_ACR);
   323		acr_value &= ~PTP_ACR_MASK;
   324		switch (priv->plat->int_snapshot_num) {
   325		case AUX_SNAPSHOT0:
   326			acr_value |= PTP_ACR_ATSEN0;
   327			break;
   328		case AUX_SNAPSHOT1:
   329			acr_value |= PTP_ACR_ATSEN1;
   330			break;
   331		case AUX_SNAPSHOT2:
   332			acr_value |= PTP_ACR_ATSEN2;
   333			break;
   334		case AUX_SNAPSHOT3:
   335			acr_value |= PTP_ACR_ATSEN3;
   336			break;
   337		default:
   338			mutex_unlock(&priv->aux_ts_lock);
   339			return -EINVAL;
   340		}
   341		writel(acr_value, ptpaddr + PTP_ACR);
   342	
   343		/* Clear FIFO */
   344		acr_value = readl(ptpaddr + PTP_ACR);
   345		acr_value |= PTP_ACR_ATSFC;
   346		writel(acr_value, ptpaddr + PTP_ACR);
   347		/* Release the mutex */
   348		mutex_unlock(&priv->aux_ts_lock);
   349	
   350		/* Trigger Internal snapshot signal. Create a rising edge by just toggle
   351		 * the GPO0 to low and back to high.
   352		 */
   353		gpio_value = readl(ioaddr + XGMAC_GPIO_STATUS);
   354		gpio_value &= ~XGMAC_GPIO_GPO0;
   355		writel(gpio_value, ioaddr + XGMAC_GPIO_STATUS);
   356		gpio_value |= XGMAC_GPIO_GPO0;
   357		writel(gpio_value, ioaddr + XGMAC_GPIO_STATUS);
   358	
   359		/* Time sync done Indication - Interrupt method */
   360		if (!wait_event_interruptible_timeout(priv->tstamp_busy_wait,
   361						      dwxgmac_cross_ts_isr(priv),
   362						      HZ / 100)) {
   363			priv->plat->flags &= ~STMMAC_FLAG_INT_SNAPSHOT_EN;
   364			return -ETIMEDOUT;
   365		}
   366	
   367		*system = (struct system_counterval_t) {
   368			.cycles = 0,
   369			.cs_id = CSID_ARM_ARCH_COUNTER,
   370			.use_nsecs = true,
   371		};
   372	
   373		num_snapshot = (readl(ioaddr + XGMAC_TIMESTAMP_STATUS) &
   374				XGMAC_TIMESTAMP_ATSNS_MASK) >>
   375				XGMAC_TIMESTAMP_ATSNS_SHIFT;
   376	
   377		/* Repeat until the timestamps are from the FIFO last segment */
   378		for (i = 0; i < num_snapshot; i++) {
   379			read_lock_irqsave(&priv->ptp_lock, flags);
   380			stmmac_get_ptptime(priv, ptpaddr, &ptp_time);
   381			*device = ns_to_ktime(ptp_time);
   382			read_unlock_irqrestore(&priv->ptp_lock, flags);
   383		}
   384	
   385		get_smtgtime(priv->mii, SMTG_MDIO_ADDR, &smtg_time);
   386		system->cycles = smtg_time;
   387	
   388		priv->plat->flags &= ~STMMAC_FLAG_INT_SNAPSHOT_EN;
   389	
 > 390		return ret;
   391	}
   392	

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