Re: [PATCH 1/3] phy: zynqmp: fix L0_TM_DISABLE_SCRAMBLE_ENCODER mask
From: Pandey, Radhey Shyam <hidden>
Date: 2026-05-20 10:37:46
Also in:
linux-phy
On 5/13/2026 3:05 AM, sashiko-bot@kernel.org wrote:
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [High] Unhandled Error Path in `xpsgtr_phy_init()` masks clock initialization failures. --
As AI review mentions - This isn't a bug introduced by this patch, but there is a pre-existing issue in xpsgtr_phy_init(). For this pre-existing issue is it ok to send a separate series and will include others error handling gaps. So far i have identified two issues. phy: zynqmp: balance pm_runtime on probe allocation failure phy: zynqmp: fix xpsgtr_phy_init() clock error handling Thanks, Radhey
commit f38f7c8479703290a0f18153b9a9207f41500566 Author: Nava kishore Manne [off-list ref] phy: zynqmp: fix L0_TM_DISABLE_SCRAMBLE_ENCODER mask The L0_TX_DIG_61 register bit 2 is a reserved read-only field. The previous mask value 0x0f incorrectly included bit 2, causing unintended writes to a reserved bit on every scrambler bypass operation. Correct the mask to (BIT(3) | GENMASK(1, 0)) to cover only the valid scramble bypass control bits.quoted
diff --git a/drivers/phy/xilinx/phy-zynqmp.c b/drivers/phy/xilinx/phy-zynqmp.c index fe6b4925d1662..c037d7c13d485 100644 --- a/drivers/phy/xilinx/phy-zynqmp.c +++ b/drivers/phy/xilinx/phy-zynqmp.c@@ -53,7 +53,7 @@ #define L0_TM_DIG_6 0x106c #define L0_TM_DIS_DESCRAMBLE_DECODER 0x0f #define L0_TX_DIG_61 0x00f4 -#define L0_TM_DISABLE_SCRAMBLE_ENCODER 0x0f +#define L0_TM_DISABLE_SCRAMBLE_ENCODER (BIT(3) | GENMASK(1, 0)) /* PLL Test Mode register parameters */ #define L0_TM_PLL_DIG_37 0x2094This isn't a bug introduced by this patch, but there is a pre-existing issue in xpsgtr_phy_init(). If clk_prepare_enable() fails, the error path appears to mask the failure: drivers/phy/xilinx/phy-zynqmp.c:xpsgtr_phy_init() { int ret = 0; mutex_lock(>r_dev->gtr_mutex); /* Configure and enable the clock when peripheral phy_init call */ if (clk_prepare_enable(gtr_dev->clk[gtr_phy->refclk])) goto out; ... out: mutex_unlock(>r_dev->gtr_mutex); return ret; } Since ret is initialized to 0, will this return 0 instead of the actual error code from clk_prepare_enable()? If the function falsely reports success, the PHY framework will consider the device initialized. During teardown, could xpsgtr_phy_exit() unconditionally call clk_disable_unprepare() on a clock that was never enabled, causing a clock reference count underflow and a kernel WARN_ON? Furthermore, would allowing the upper layer to access PHY registers without a running clock risk hanging the AXI bus on ZynqMP, potentially leading to an asynchronous external abort (system panic)?