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Wed, 19 Apr 2023 09:57:42 -0700 (PDT) Received: from stbsrv-and-01.and.broadcom.net ([192.19.144.250]) by smtp.gmail.com with ESMTPSA id s9-20020aa78d49000000b005abc30d9445sm11188135pfe.180.2023.04.19.09.57.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Apr 2023 09:57:42 -0700 (PDT) From: Jim Quinlan To: linux-pci@vger.kernel.org, Nicolas Saenz Julienne , Bjorn Helgaas , Lorenzo Pieralisi , Cyril Brulebois , Phil Elwell , bcm-kernel-feedback-list@broadcom.com, jim2101024@gmail.com, james.quinlan@broadcom.com Cc: Florian Fainelli , Lorenzo Pieralisi , =?utf-8?q?Krzysztof_Wilczy=C5=84?= =?utf-8?q?ski?= , Rob Herring , Krzysztof Kozlowski , linux-rpi-kernel@lists.infradead.org (moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE), linux-arm-kernel@lists.infradead.org (moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE), devicetree@vger.kernel.org (open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS), linux-kernel@vger.kernel.org (open list) Subject: [PATCH v3 1/3] dt-bindings: PCI: brcmstb: brcm,{enable-l1ss,completion-timeout-us} props Date: Wed, 19 Apr 2023 12:57:18 -0400 Message-Id: <20230419165721.29533-2-jim2101024@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230419165721.29533-1-jim2101024@gmail.com> References: <20230419165721.29533-1-jim2101024@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230419_095745_609152_4E449AA5 X-CRM114-Status: GOOD ( 16.14 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org This commit introduces two new properties: brcm,enable-l1ss (bool): The Broadcom STB/CM PCIe HW -- a core that is also used by RPi SOCs -- requires the driver probe() to deliberately place the HW one of three CLKREQ# modes: (a) CLKREQ# driven by the RC unconditionally (b) CLKREQ# driven by the EP for ASPM L0s, L1 (c) Bidirectional CLKREQ#, as used for L1 Substates (L1SS). The HW+driver can tell the difference between downstream devices that need (a) and (b), but does not know when to configure (c). All devices should work fine when the driver chooses (a) or (b), but (c) may be desired to realize the extra power savings that L1SS offers. So we introduce the boolean "brcm,enable-l1ss" property to inform the driver that (c) is desired. Setting this property only makes sense when the downstream device is L1SS-capable and the OS is configured to activate this mode (e.g. policy==superpowersave). This property is already present in the Raspian version of Linux, but the upstream driver implementaion that follows adds more details and discerns between (a) and (b). brcm,completion-timeout-us (u32): Our HW will cause a CPU abort on any PCI transaction completion abort error. It makes sense then to increase the timeout value for this type of error in hopes that the response is merely delayed. Further, L1SS-capable devices may have a long L1SS exit time and may require a custom timeout value: we've been asked by our customers to make this configurable for just this reason. Signed-off-by: Jim Quinlan Reviewed-by: Rob Herring --- .../devicetree/bindings/pci/brcm,stb-pcie.yaml | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml index 7e15aae7d69e..239cc95545bd 100644 --- a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml +++ b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml @@ -64,6 +64,22 @@ properties: aspm-no-l0s: true + brcm,enable-l1ss: + description: Indicates that PCIe L1SS power savings + are desired, the downstream device is L1SS-capable, and the + OS has been configured to enable this mode. For boards + using a mini-card connector, this mode may not meet the + TCRLon maximum time of 400ns, as specified in 3.2.5.2.5 + of the PCI Express Mini CEM 2.0 specification. + type: boolean + + brcm,completion-timeout-us: + description: Number of microseconds before PCI transaction + completion timeout abort is signalled. + minimum: 16 + default: 1000000 + maximum: 19884107 + brcm,scb-sizes: description: u64 giving the 64bit PCIe memory viewport size of a memory controller. 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Wed, 19 Apr 2023 09:57:45 -0700 (PDT) Received: from stbsrv-and-01.and.broadcom.net ([192.19.144.250]) by smtp.gmail.com with ESMTPSA id s9-20020aa78d49000000b005abc30d9445sm11188135pfe.180.2023.04.19.09.57.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Apr 2023 09:57:45 -0700 (PDT) From: Jim Quinlan To: linux-pci@vger.kernel.org, Nicolas Saenz Julienne , Bjorn Helgaas , Lorenzo Pieralisi , Cyril Brulebois , Phil Elwell , bcm-kernel-feedback-list@broadcom.com, jim2101024@gmail.com, james.quinlan@broadcom.com Cc: Florian Fainelli , Lorenzo Pieralisi , =?utf-8?q?Krzysztof_Wilczy=C5=84?= =?utf-8?q?ski?= , Rob Herring , linux-rpi-kernel@lists.infradead.org (moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE), linux-arm-kernel@lists.infradead.org (moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE), linux-kernel@vger.kernel.org (open list) Subject: [PATCH v3 2/3] PCI: brcmstb: Configure HW CLKREQ# mode appropriate for downstream device Date: Wed, 19 Apr 2023 12:57:19 -0400 Message-Id: <20230419165721.29533-3-jim2101024@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230419165721.29533-1-jim2101024@gmail.com> References: <20230419165721.29533-1-jim2101024@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230419_095748_485288_B80EB083 X-CRM114-Status: GOOD ( 20.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The Broadcom STB/CM PCIe HW core, which is also used in RPi SOCs, must be deliberately set by the RC probe() into one of three mutually exclusive modes: (a) No CLKREQ# expected or required, refclk is always available. (b) CLKREQ# is expected to be driven by downstream device when needed. (c) Bidirectional CLKREQ# for L1SS capable devices. Previously, only (b) was supported by the driver, as almost all STB/CM boards operate in this mode. But now there is interest in activating L1SS power savings from STB/CM customers, and also interest in accommodating mode (a) for designs such as the RPi CM4 with IO board. The HW+driver is able to tell us when mode (a) or (b) is needed. All devices should be functional using the RC-driver selected (a) or (b) mode. For those with L1SS-capable devices that desire the power savings that come with mode (c) we rely on the DT prop "brcm,enable-l1ss". It would be nice to do this automatically but there is no easy way to determine this at the time the PCI RC driver executes its probe(). Using this mode only makes sense when the downstream device is L1SS-capable and the OS has been configured to activate L1SS (e.g. policy==powersupersave). The "brcm,enable-l1ss" property has already been in use by Raspian Linux, but this implementation adds more details and discerns between (a) and (b) automatically. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217276 Tested-by: Florian Fainelli Signed-off-by: Jim Quinlan --- drivers/pci/controller/pcie-brcmstb.c | 69 +++++++++++++++++++++++---- 1 file changed, 59 insertions(+), 10 deletions(-) diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c index edf283e2b5dd..c4b076ea5180 100644 --- a/drivers/pci/controller/pcie-brcmstb.c +++ b/drivers/pci/controller/pcie-brcmstb.c @@ -48,10 +48,17 @@ #define PCIE_RC_CFG_PRIV1_LINK_CAPABILITY 0x04dc #define PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK 0xc00 +#define PCIE_RC_CFG_PRIV1_ROOT_CAP 0x4f8 +#define PCIE_RC_CFG_PRIV1_ROOT_CAP_L1SS_MODE_MASK 0xf8 + #define PCIE_RC_DL_MDIO_ADDR 0x1100 #define PCIE_RC_DL_MDIO_WR_DATA 0x1104 #define PCIE_RC_DL_MDIO_RD_DATA 0x1108 +#define PCIE_0_RC_PL_PHY_DBG_CLKREQ2_0 0x1e30 +#define CLKREQ2_0_CLKREQ_IN_CNT_MASK 0x3f000000 +#define CLKREQ2_0_CLKREQ_IN_MASK 0x40000000 + #define PCIE_MISC_MISC_CTRL 0x4008 #define PCIE_MISC_MISC_CTRL_PCIE_RCB_64B_MODE_MASK 0x80 #define PCIE_MISC_MISC_CTRL_PCIE_RCB_MPS_MODE_MASK 0x400 @@ -121,9 +128,12 @@ #define PCIE_MISC_HARD_PCIE_HARD_DEBUG 0x4204 #define PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK 0x2 +#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_L1SS_ENABLE_MASK 0x200000 #define PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK 0x08000000 #define PCIE_BMIPS_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK 0x00800000 - +#define PCIE_CLKREQ_MASK \ + (PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK | \ + PCIE_MISC_HARD_PCIE_HARD_DEBUG_L1SS_ENABLE_MASK) #define PCIE_INTR2_CPU_BASE 0x4300 #define PCIE_MSI_INTR2_BASE 0x4500 @@ -1024,13 +1034,58 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie) return 0; } +static void brcm_config_clkreq(struct brcm_pcie *pcie) +{ + bool l1ss = of_property_read_bool(pcie->np, "brcm,enable-l1ss"); + void __iomem *base = pcie->base; + u32 clkreq_set, tmp = readl(base + PCIE_0_RC_PL_PHY_DBG_CLKREQ2_0); + bool clkreq_in_seen; + + /* + * We have "seen" CLKREQ# if it is asserted or has been in the past. + * Note that the CLKREQ_IN_MASK is 1 if CLKREQ# is asserted. + */ + clkreq_in_seen = !!(tmp & CLKREQ2_0_CLKREQ_IN_MASK) || + !!FIELD_GET(CLKREQ2_0_CLKREQ_IN_CNT_MASK, tmp); + + /* Start with safest setting where we provide refclk regardless */ + clkreq_set = readl(pcie->base + PCIE_MISC_HARD_PCIE_HARD_DEBUG) & + ~PCIE_CLKREQ_MASK; + + if (l1ss && IS_ENABLED(CONFIG_PCIEASPM)) { + /* + * Note: For boards using a mini-card connector, this mode + * may not meet the TCRLon maximum time of 400ns, as + * specified in 3.2.5.2.5 of the PCI Express Mini CEM 2.0 + * specification. + */ + clkreq_set |= PCIE_MISC_HARD_PCIE_HARD_DEBUG_L1SS_ENABLE_MASK; + dev_info(pcie->dev, "bi-dir CLKREQ# for L1SS power savings"); + } else { + if (clkreq_in_seen && IS_ENABLED(CONFIG_PCIEASPM)) { + clkreq_set |= PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK; + dev_info(pcie->dev, "uni-dir CLKREQ# for L0s, L1 ASPM\n"); + } else { + dev_info(pcie->dev, "CLKREQ# ignored; no ASPM\n"); + /* Might as well unadvertise ASPM */ + tmp = readl(base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY) & + ~PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK; + writel(tmp, base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY); + } + /* Setting the field to 2 unadvertises L1SS support */ + tmp = readl(base + PCIE_RC_CFG_PRIV1_ROOT_CAP); + u32p_replace_bits(&tmp, 2, PCIE_RC_CFG_PRIV1_ROOT_CAP_L1SS_MODE_MASK); + writel(tmp, base + PCIE_RC_CFG_PRIV1_ROOT_CAP); + } + writel(clkreq_set, pcie->base + PCIE_MISC_HARD_PCIE_HARD_DEBUG); +} + static int brcm_pcie_start_link(struct brcm_pcie *pcie) { struct device *dev = pcie->dev; void __iomem *base = pcie->base; u16 nlw, cls, lnksta; bool ssc_good = false; - u32 tmp; int ret, i; /* Unassert the fundamental reset */ @@ -1055,6 +1110,8 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie) return -ENODEV; } + brcm_config_clkreq(pcie); + if (pcie->gen) brcm_pcie_set_gen(pcie, pcie->gen); @@ -1073,14 +1130,6 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie) pci_speed_string(pcie_link_speed[cls]), nlw, ssc_good ? "(SSC)" : "(!SSC)"); - /* - * Refclk from RC should be gated with CLKREQ# input when ASPM L0s,L1 - * is enabled => setting the CLKREQ_DEBUG_ENABLE field to 1. - */ - tmp = readl(base + PCIE_MISC_HARD_PCIE_HARD_DEBUG); - tmp |= PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK; - writel(tmp, base + PCIE_MISC_HARD_PCIE_HARD_DEBUG); - return 0; } From patchwork Wed Apr 19 16:57:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Quinlan X-Patchwork-Id: 13217149 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 36FA3C77B73 for ; Wed, 19 Apr 2023 16:58:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; 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Further, different devices and systems may requires a larger or smaller amount commensurate with their L1SS exit time, so the property "brcm,completion-timeout-us" may be used to set a custom timeout value. Tested-by: Florian Fainelli Signed-off-by: Jim Quinlan --- drivers/pci/controller/pcie-brcmstb.c | 30 +++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c index c4b076ea5180..c2cb683447ac 100644 --- a/drivers/pci/controller/pcie-brcmstb.c +++ b/drivers/pci/controller/pcie-brcmstb.c @@ -1080,6 +1080,35 @@ static void brcm_config_clkreq(struct brcm_pcie *pcie) writel(clkreq_set, pcie->base + PCIE_MISC_HARD_PCIE_HARD_DEBUG); } +static void brcm_config_completion_timeout(struct brcm_pcie *pcie) +{ + /* TIMEOUT register is two registers before RGR1_SW_INIT_1 */ + const char *fmt = "brcm,completion-timeout-us clamped to region [%u..%u]\n"; + const unsigned int REG_OFFSET = PCIE_RGR1_SW_INIT_1(pcie) - 8; + const u32 timeout_us_min = 16; + const u32 timeout_us_max = 19884107; + u32 timeout_us = 1000000; /* Our default, 1 second */ + int rval, ret; + + ret = of_property_read_u32(pcie->np, "brcm,completion-timeout-us", + &timeout_us); + if (ret && ret != -EINVAL) + dev_err(pcie->dev, "malformed/invalid 'brcm,completion-timeout-us'\n"); + + /* If needed, clamp the requested timeout value and issue a warning */ + if (timeout_us < timeout_us_min) { + timeout_us = timeout_us_min; + dev_warn(pcie->dev, fmt, timeout_us_min, timeout_us_max); + } else if (timeout_us > timeout_us_max) { + timeout_us = timeout_us_max; + dev_warn(pcie->dev, fmt, timeout_us_min, timeout_us_max); + } + + /* Each unit in timeout register is 1/216,000,000 seconds */ + rval = 216 * timeout_us; + writel(rval, pcie->base + REG_OFFSET); +} + static int brcm_pcie_start_link(struct brcm_pcie *pcie) { struct device *dev = pcie->dev; @@ -1110,6 +1139,7 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie) return -ENODEV; } + brcm_config_completion_timeout(pcie); brcm_config_clkreq(pcie); if (pcie->gen)