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From: Bjorn Helgaas <helgaas@kernel.org>
To: Niklas Cassel <cassel@kernel.org>, Shawn Lin <shawn.lin@rock-chips.com>
Cc: "Manivannan Sadhasivam" <mani@kernel.org>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
	"Rob Herring" <robh@kernel.org>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Kever Yang" <kever.yang@rock-chips.com>,
	"Simon Xue" <xxm@rock-chips.com>,
	"Damien Le Moal" <dlemoal@kernel.org>,
	"Dragan Simic" <dsimic@manjaro.org>,
	"FUKAUMI Naoki" <naoki@radxa.com>,
	"Diederik de Haas" <diederik@cknow-tech.com>,
	"Richard Zhu" <hongxing.zhu@nxp.com>,
	"Frank Li" <Frank.li@nxp.com>,
	"Lucas Stach" <l.stach@pengutronix.de>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Fabio Estevam" <festevam@gmail.com>,
	"Conor Dooley" <conor@kernel.org>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Jonathan Hunter" <jonathanh@nvidia.com>,
	"Hans Zhang" <hans.zhang@cixtech.com>,
	linux-tegra@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, kernel@pengutronix.de,
	"Bjorn Helgaas" <bhelgaas@google.com>
Subject: [PATCH v2 2/4] PCI: tegra194: Remove unnecessary L1SS disable code
Date: Tue, 18 Nov 2025 15:42:16 -0600	[thread overview]
Message-ID: <20251118214312.2598220-3-helgaas@kernel.org> (raw)
In-Reply-To: <20251118214312.2598220-1-helgaas@kernel.org>

From: Bjorn Helgaas <bhelgaas@google.com>

The DWC core clears the L1 Substates Supported bits unless the driver sets
the "dw_pcie.l1ss_support" flag.

The tegra194 init_host_aspm() sets "dw_pcie.l1ss_support" if the platform
has the "supports-clkreq" DT property.  If "supports-clkreq" is absent,
"dw_pcie.l1ss_support" is not set, and the DWC core will clear the L1
Substates Supported bits.

The tegra194 code to clear the L1 Substates Supported bits is unnecessary,
so remove it.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/controller/dwc/pcie-tegra194.c | 45 +++-------------------
 1 file changed, 5 insertions(+), 40 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 3934757baa30..0ddeef70726d 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -260,7 +260,6 @@ struct tegra_pcie_dw {
 	u32 msi_ctrl_int;
 	u32 num_lanes;
 	u32 cid;
-	u32 cfg_link_cap_l1sub;
 	u32 ras_des_cap;
 	u32 pcie_cap_base;
 	u32 aspm_cmrt;
@@ -475,8 +474,7 @@ static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg)
 		return IRQ_HANDLED;
 
 	/* If EP doesn't advertise L1SS, just return */
-	val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub);
-	if (!(val & (PCI_L1SS_CAP_ASPM_L1_1 | PCI_L1SS_CAP_ASPM_L1_2)))
+	if (!pci->l1ss_support)
 		return IRQ_HANDLED;
 
 	/* Check if BME is set to '1' */
@@ -608,24 +606,6 @@ static struct pci_ops tegra_pci_ops = {
 };
 
 #if defined(CONFIG_PCIEASPM)
-static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
-{
-	u32 val;
-
-	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
-	val &= ~PCI_L1SS_CAP_ASPM_L1_1;
-	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
-}
-
-static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
-{
-	u32 val;
-
-	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
-	val &= ~PCI_L1SS_CAP_ASPM_L1_2;
-	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
-}
-
 static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
 {
 	u32 val;
@@ -682,10 +662,9 @@ static int aspm_state_cnt(struct seq_file *s, void *data)
 static void init_host_aspm(struct tegra_pcie_dw *pcie)
 {
 	struct dw_pcie *pci = &pcie->pci;
-	u32 val;
+	u32 l1ss, val;
 
-	val = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS);
-	pcie->cfg_link_cap_l1sub = val + PCI_L1SS_CAP;
+	l1ss = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS);
 
 	pcie->ras_des_cap = dw_pcie_find_ext_capability(&pcie->pci,
 							PCI_EXT_CAP_ID_VNDR);
@@ -697,11 +676,11 @@ static void init_host_aspm(struct tegra_pcie_dw *pcie)
 			   PCIE_RAS_DES_EVENT_COUNTER_CONTROL, val);
 
 	/* Program T_cmrt and T_pwr_on values */
-	val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub);
+	val = dw_pcie_readl_dbi(pci, l1ss + PCI_L1SS_CAP);
 	val &= ~(PCI_L1SS_CAP_CM_RESTORE_TIME | PCI_L1SS_CAP_P_PWR_ON_VALUE);
 	val |= (pcie->aspm_cmrt << 8);
 	val |= (pcie->aspm_pwr_on_t << 19);
-	dw_pcie_writel_dbi(pci, pcie->cfg_link_cap_l1sub, val);
+	dw_pcie_writel_dbi(pci, l1ss + PCI_L1SS_CAP, val);
 
 	if (pcie->supports_clkreq)
 		pci->l1ss_support = true;
@@ -729,8 +708,6 @@ static void init_debugfs(struct tegra_pcie_dw *pcie)
 				    aspm_state_cnt);
 }
 #else
-static inline void disable_aspm_l12(struct tegra_pcie_dw *pcie) { return; }
-static inline void disable_aspm_l11(struct tegra_pcie_dw *pcie) { return; }
 static inline void init_host_aspm(struct tegra_pcie_dw *pcie) { return; }
 static inline void init_debugfs(struct tegra_pcie_dw *pcie) { return; }
 #endif
@@ -934,12 +911,6 @@ static int tegra_pcie_dw_host_init(struct dw_pcie_rp *pp)
 
 	init_host_aspm(pcie);
 
-	/* Disable ASPM-L1SS advertisement if there is no CLKREQ routing */
-	if (!pcie->supports_clkreq) {
-		disable_aspm_l11(pcie);
-		disable_aspm_l12(pcie);
-	}
-
 	if (!pcie->of_data->has_l1ss_exit_fix) {
 		val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
 		val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
@@ -1874,12 +1845,6 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
 
 	init_host_aspm(pcie);
 
-	/* Disable ASPM-L1SS advertisement if there is no CLKREQ routing */
-	if (!pcie->supports_clkreq) {
-		disable_aspm_l11(pcie);
-		disable_aspm_l12(pcie);
-	}
-
 	if (!pcie->of_data->has_l1ss_exit_fix) {
 		val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
 		val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
-- 
2.43.0


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  parent reply	other threads:[~2025-11-18 21:43 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-18 21:42 [PATCH v2 0/4] PCI: dwc: Advertise L1 PM Substates only if driver requests it Bjorn Helgaas
2025-11-18 21:42 ` [PATCH v2 1/4] " Bjorn Helgaas
2025-11-18 22:20   ` Frank Li
2025-11-18 22:45     ` Niklas Cassel
2025-11-19  0:45       ` Frank Li
2025-11-18 22:34   ` Frank Li
2025-11-19 11:08     ` Niklas Cassel
2025-11-19 15:58       ` Frank Li
2025-11-20  0:53         ` Shawn Lin
2025-11-24 21:22       ` Bjorn Helgaas
2025-11-20  7:52     ` Manivannan Sadhasivam
2025-11-20  7:40   ` Manivannan Sadhasivam
2025-11-24 21:19     ` Bjorn Helgaas
2025-11-25  5:25       ` Manivannan Sadhasivam
2025-11-18 21:42 ` Bjorn Helgaas [this message]
2025-11-18 21:42 ` [PATCH v2 3/4] PCI: dw-rockchip: Configure L1SS support Bjorn Helgaas
2025-11-18 21:42 ` [PATCH v2 4/4] arm64: dts: rockchip: Add PCIe clkreq stuff for RK3588 EVB1 Bjorn Helgaas
2025-11-24 22:50 ` [PATCH v2 0/4] PCI: dwc: Advertise L1 PM Substates only if driver requests it Bjorn Helgaas

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