From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-m49238.qiye.163.com (mail-m49238.qiye.163.com [45.254.49.238]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D2DA24BBEB; Mon, 12 Jan 2026 01:56:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.254.49.238 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768182987; cv=none; b=qiGZD0+yeF8kLLYd7j5BCOfNgZIBiIelj2LqZb4V8418unNsJCAbBTEaUhHJ+hJtdK/qB5E81R6cjLYJVa1DfJd6HJ9iXOnyRF5tKcdnHvJdwcmq5BlaNWmFQbZ0B07U5uy0uoLN39J87t9/NK5dwWQ/WO/TmM9o7Y2lcgSQAz4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768182987; c=relaxed/simple; bh=85V/kSD5DV50NM9PuhTGBYZFnOYu1dLPby/MWS87gM8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=UvvDYNSRDrSRgFZcCcBK2ZShxNYFk9KSSnHnT5nxYrilnPRpXKBh2OEMV3e8EPEkgeD3hX8dLdLjwXqY8ASRHdK8GvbEyFqgxLit8x1AiF+u/SFzwifuMUVuixtlzwdUZEFn/DSzrFp2CVqfdxxsydWm+POESbELfTl/UGUfa98= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rock-chips.com; spf=pass smtp.mailfrom=rock-chips.com; dkim=pass (1024-bit key) header.d=rock-chips.com header.i=@rock-chips.com header.b=Oxd0oj2q; arc=none smtp.client-ip=45.254.49.238 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rock-chips.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rock-chips.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=rock-chips.com header.i=@rock-chips.com header.b="Oxd0oj2q" Received: from localhost.localdomain (unknown [58.22.7.114]) by smtp.qiye.163.com (Hmail) with ESMTP id 303e91937; Mon, 12 Jan 2026 09:20:33 +0800 (GMT+08:00) From: Shawn Lin To: Manivannan Sadhasivam , Bjorn Helgaas Cc: linux-rockchip@lists.infradead.org, linux-pci@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Steven Rostedt , Masami Hiramatsu , Shawn Lin Subject: [PATCH v3 3/3] PCI: dw-rockchip: Add pcie_ltssm_state_transition trace support Date: Mon, 12 Jan 2026 09:20:00 +0800 Message-Id: <1768180800-63364-4-git-send-email-shawn.lin@rock-chips.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1768180800-63364-1-git-send-email-shawn.lin@rock-chips.com> References: <1768180800-63364-1-git-send-email-shawn.lin@rock-chips.com> X-HM-Tid: 0a9bafca5b9109cckunme7c7221b25b240 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFDSUNOT01LS0k3V1ktWUFJV1kPCRoVCBIfWUFZGksaTFZITBgfQ0hKSB9KTxpWFRQJFh oXVRMBExYaEhckFA4PWVdZGBILWUFZTkNVSUlVTFVKSk9ZV1kWGg8SFR0UWUFZT0tIVUpLSU9PT0 hVSktLVUpCS0tZBg++ DKIM-Signature: a=rsa-sha256; b=Oxd0oj2qIKPgVMH/gYNeLYzPhsF9UrEMkF0ZkPa2uQG/p5D0nhzXQPAdYuKasOkyj87H6dR8vc2E+xAPSGr0RMxCQfHp4nXgIeTOKtjhAmbZsYpSJsQ3bo9ochxnDXSfMnv9bBEdqA7wfDGHxM3QdczLRKI0g6CAMRV7rpl0KtQ=; s=default; c=relaxed/relaxed; d=rock-chips.com; v=1; bh=ZgxJOYtEUZZ9lDjUn8KCpSUAe2bzrN8TYgmqnZ6nm/I=; h=date:mime-version:subject:message-id:from; Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Rockchip platforms provide a 64x4 bytes debug FIFO to trace the LTSSM history. Any LTSSM change will be recorded. It's userful for debug purpose, for example link failure, etc. Signed-off-by: Shawn Lin --- Changes in v3: - reorder variables(Mani) - rename loop to i; rename en to enable(Mani) - use FIELD_GET(Mani) - add comment about how the FIFO works(Mani) Changes in v2: - use tracepoint drivers/pci/controller/dwc/pcie-dw-rockchip.c | 104 ++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c index 352f513..344e0b9 100644 --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c @@ -22,6 +22,8 @@ #include #include #include +#include +#include #include "../../pci.h" #include "pcie-designware.h" @@ -73,6 +75,20 @@ #define PCIE_CLIENT_CDM_RASDES_TBA_L1_1 BIT(4) #define PCIE_CLIENT_CDM_RASDES_TBA_L1_2 BIT(5) +/* Debug FIFO information */ +#define PCIE_CLIENT_DBG_FIFO_MODE_CON 0x310 +#define PCIE_CLIENT_DBG_EN 0xffff0007 +#define PCIE_CLIENT_DBG_DIS 0xffff0000 +#define PCIE_CLIENT_DBG_FIFO_PTN_HIT_D0 0x320 +#define PCIE_CLIENT_DBG_FIFO_PTN_HIT_D1 0x324 +#define PCIE_CLIENT_DBG_FIFO_TRN_HIT_D0 0x328 +#define PCIE_CLIENT_DBG_FIFO_TRN_HIT_D1 0x32c +#define PCIE_CLIENT_DBG_TRANSITION_DATA 0xffff0000 +#define PCIE_CLIENT_DBG_FIFO_STATUS 0x350 +#define PCIE_DBG_FIFO_RATE_MASK GENMASK(22, 20) +#define PCIE_DBG_FIFO_L1SUB_MASK GENMASK(10, 8) +#define PCIE_DBG_LTSSM_HISTORY_CNT 64 + /* Hot Reset Control Register */ #define PCIE_CLIENT_HOT_RESET_CTRL 0x180 #define PCIE_LTSSM_APP_DLY2_EN BIT(1) @@ -96,6 +112,7 @@ struct rockchip_pcie { struct irq_domain *irq_domain; const struct rockchip_pcie_of_data *data; bool supports_clkreq; + struct delayed_work trace_work; }; struct rockchip_pcie_of_data { @@ -206,6 +223,89 @@ static enum dw_pcie_ltssm rockchip_pcie_get_ltssm(struct dw_pcie *pci) return rockchip_pcie_get_ltssm_reg(rockchip) & PCIE_LTSSM_STATUS_MASK; } +#ifdef CONFIG_TRACING +static void rockchip_pcie_ltssm_trace_work(struct work_struct *work) +{ + struct rockchip_pcie *rockchip = container_of(work, struct rockchip_pcie, + trace_work.work); + struct dw_pcie *pci = &rockchip->pci; + enum dw_pcie_ltssm state; + u32 i, l1ss, prev_val = DW_PCIE_LTSSM_UNKNOWN, rate, val; + + for (i = 0; i < PCIE_DBG_LTSSM_HISTORY_CNT; i++) { + val = rockchip_pcie_readl_apb(rockchip, PCIE_CLIENT_DBG_FIFO_STATUS); + rate = FIELD_GET(PCIE_DBG_FIFO_RATE_MASK, val); + l1ss = FIELD_GET(PCIE_DBG_FIFO_L1SUB_MASK, val); + val = FIELD_GET(PCIE_LTSSM_STATUS_MASK, val); + + /* + * Hardware Mechanism: The ring FIFO employs two tracking counters: + * - 'last-read-point': maintains the user's last read position + * - 'last-valid-point': tracks the hardware's last state update + * + * Software Handling: When two consecutive LTSSM states are identical, + * it indicates invalid subsequent data in the FIFO. In this case, we + * skip the remaining entries. The dual-counter design ensures that on + * the next state transition, reading can resume from the last user + * position. + */ + if ((i > 0 && val == prev_val) || val > DW_PCIE_LTSSM_RCVRY_EQ3) + break; + + state = prev_val = val; + if (val == DW_PCIE_LTSSM_L1_IDLE) { + if (l1ss == 2) + state = DW_PCIE_LTSSM_L1_2; + else if (l1ss == 1) + state = DW_PCIE_LTSSM_L1_1; + } + + trace_pcie_ltssm_state_transition(dev_name(pci->dev), + dw_pcie_ltssm_status_string(state), + ((rate + 1) > pci->max_link_speed) ? + PCI_SPEED_UNKNOWN : PCIE_SPEED_2_5GT + rate); + } + + schedule_delayed_work(&rockchip->trace_work, msecs_to_jiffies(5000)); +} + +static void rockchip_pcie_ltssm_trace(struct rockchip_pcie *rockchip, + bool enable) +{ + if (enable) { + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_TRANSITION_DATA, + PCIE_CLIENT_DBG_FIFO_PTN_HIT_D0); + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_TRANSITION_DATA, + PCIE_CLIENT_DBG_FIFO_PTN_HIT_D1); + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_TRANSITION_DATA, + PCIE_CLIENT_DBG_FIFO_TRN_HIT_D0); + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_TRANSITION_DATA, + PCIE_CLIENT_DBG_FIFO_TRN_HIT_D1); + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_EN, + PCIE_CLIENT_DBG_FIFO_MODE_CON); + + INIT_DELAYED_WORK(&rockchip->trace_work, + rockchip_pcie_ltssm_trace_work); + schedule_delayed_work(&rockchip->trace_work, 0); + } else { + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_DIS, + PCIE_CLIENT_DBG_FIFO_MODE_CON); + cancel_delayed_work_sync(&rockchip->trace_work); + } +} +#else +static void rockchip_pcie_ltssm_trace(struct rockchip_pcie *rockchip, + bool enable) +{ +} +#endif + static void rockchip_pcie_enable_ltssm(struct rockchip_pcie *rockchip) { rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_ENABLE_LTSSM, @@ -289,6 +389,9 @@ static int rockchip_pcie_start_link(struct dw_pcie *pci) * 100us as we don't know how long should the device need to reset. */ msleep(PCIE_T_PVPERL_MS); + + rockchip_pcie_ltssm_trace(rockchip, true); + gpiod_set_value_cansleep(rockchip->rst_gpio, 1); return 0; @@ -299,6 +402,7 @@ static void rockchip_pcie_stop_link(struct dw_pcie *pci) struct rockchip_pcie *rockchip = to_rockchip_pcie(pci); rockchip_pcie_disable_ltssm(rockchip); + rockchip_pcie_ltssm_trace(rockchip, false); } static int rockchip_pcie_host_init(struct dw_pcie_rp *pp) -- 2.7.4