From patchwork Thu Oct 28 18:56:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Marek_Beh=C3=BAn?= X-Patchwork-Id: 12590909 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07347C433FE for ; Thu, 28 Oct 2021 18:57:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2CA76023E for ; Thu, 28 Oct 2021 18:57:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230517AbhJ1S7f (ORCPT ); Thu, 28 Oct 2021 14:59:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:57030 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230505AbhJ1S7e (ORCPT ); Thu, 28 Oct 2021 14:59:34 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D317460232; Thu, 28 Oct 2021 18:57:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635447427; bh=dqIcLzKobLU15jhsBn8y0D5cnA9xwu5wfL8NwiVCOcg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OSGyRzkSqWcqKk/nBaxU/pmpG4vK/ik0s+6UsYMkRaE+wZtUDglVxiQ7AaAthxteY hjN4eWyio6tDD++VciI6Lo6NA7qe+rT4HfOmqsrU/HZrnbvXG8zi91puh3fu97IOkK XgcvTXH8O0luxYhw3C7ORsxihW9d4l/2ubIgtJ7wfUTCdu9Zj3ckdxe+KJiTV3UB+t z4iJMyE4SDz1Z+MIvaPdyLbkGY5MDMF2+vPyoI6yI9G7KzILTuYmrmuTtUzFeRpO+u qAkaOUqDjjs1Db0s/bvmln6dYVB5T00IEX9w1guV5pauS66wVAt8Pq1KxDgiSmqXDH qnWItPrICcfDg== From: =?utf-8?q?Marek_Beh=C3=BAn?= To: Lorenzo Pieralisi Cc: linux-pci@vger.kernel.org, pali@kernel.org, =?utf-8?q?Marek_Beh=C3=BAn?= Subject: [PATCH v2 4/7] PCI: aardvark: Fix support for bus mastering and PCI_COMMAND on emulated bridge Date: Thu, 28 Oct 2021 20:56:56 +0200 Message-Id: <20211028185659.20329-5-kabel@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211028185659.20329-1-kabel@kernel.org> References: <20211028185659.20329-1-kabel@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Pali Rohár From very vague, ambiguous and incomplete information from Marvell we deduced that the 32-bit Aardvark register at address 0x4 (PCIE_CORE_CMD_STATUS_REG), which is not documented for Root Complex mode in the Functional Specification (only for Endpoint mode), controls two 16-bit PCIe registers: Command Register and Status Registers of PCIe Root Port. This means that bit 2 controls bus mastering and forwarding of memory and I/O requests in the upstream direction. According to PCI specifications bits [0:2] of Command Register, this should be by default disabled on reset. So explicitly disable these bits at early setup of the Aardvark driver. Remove code which unconditionally enables all 3 bits and let kernel code (via pci_set_master() function) to handle bus mastering of Root PCIe Bridge via emulated PCI_COMMAND on emulated bridge. Fixes: 8a3ebd8de328 ("PCI: aardvark: Implement emulated root PCI bridge config space") Signed-off-by: Pali Rohár Signed-off-by: Marek Behún Cc: stable@vger.kernel.org # b2a56469d550 ("PCI: aardvark: Add FIXME comment for PCIE_CORE_CMD_STATUS_REG access") --- drivers/pci/controller/pci-aardvark.c | 54 +++++++++++++++++++-------- 1 file changed, 38 insertions(+), 16 deletions(-) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index 389ebba1dd9b..d7db03da4d1c 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -31,9 +31,6 @@ /* PCIe core registers */ #define PCIE_CORE_DEV_ID_REG 0x0 #define PCIE_CORE_CMD_STATUS_REG 0x4 -#define PCIE_CORE_CMD_IO_ACCESS_EN BIT(0) -#define PCIE_CORE_CMD_MEM_ACCESS_EN BIT(1) -#define PCIE_CORE_CMD_MEM_IO_REQ_EN BIT(2) #define PCIE_CORE_DEV_REV_REG 0x8 #define PCIE_CORE_PCIEXP_CAP 0xc0 #define PCIE_CORE_ERR_CAPCTL_REG 0x118 @@ -514,6 +511,11 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie) reg = (PCI_VENDOR_ID_MARVELL << 16) | PCI_VENDOR_ID_MARVELL; advk_writel(pcie, reg, VENDOR_ID_REG); + /* Disable Root Bridge I/O space, memory space and bus mastering */ + reg = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG); + reg &= ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER); + advk_writel(pcie, reg, PCIE_CORE_CMD_STATUS_REG); + /* Set Advanced Error Capabilities and Control PF0 register */ reg = PCIE_CORE_ERR_CAPCTL_ECRC_CHK_TX | PCIE_CORE_ERR_CAPCTL_ECRC_CHK_TX_EN | @@ -612,19 +614,6 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie) advk_pcie_disable_ob_win(pcie, i); advk_pcie_train_link(pcie); - - /* - * FIXME: The following register update is suspicious. This register is - * applicable only when the PCI controller is configured for Endpoint - * mode, not as a Root Complex. But apparently when this code is - * removed, some cards stop working. This should be investigated and - * a comment explaining this should be put here. - */ - reg = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG); - reg |= PCIE_CORE_CMD_MEM_ACCESS_EN | - PCIE_CORE_CMD_IO_ACCESS_EN | - PCIE_CORE_CMD_MEM_IO_REQ_EN; - advk_writel(pcie, reg, PCIE_CORE_CMD_STATUS_REG); } static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u32 *val) @@ -753,6 +742,37 @@ static int advk_pcie_wait_pio(struct advk_pcie *pcie) return -ETIMEDOUT; } +static pci_bridge_emul_read_status_t +advk_pci_bridge_emul_base_conf_read(struct pci_bridge_emul *bridge, + int reg, u32 *value) +{ + struct advk_pcie *pcie = bridge->data; + + switch (reg) { + case PCI_COMMAND: + *value = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG); + return PCI_BRIDGE_EMUL_HANDLED; + + default: + return PCI_BRIDGE_EMUL_NOT_HANDLED; + } +} + +static void +advk_pci_bridge_emul_base_conf_write(struct pci_bridge_emul *bridge, + int reg, u32 old, u32 new, u32 mask) +{ + struct advk_pcie *pcie = bridge->data; + + switch (reg) { + case PCI_COMMAND: + advk_writel(pcie, new, PCIE_CORE_CMD_STATUS_REG); + break; + + default: + break; + } +} static pci_bridge_emul_read_status_t advk_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge, @@ -854,6 +874,8 @@ advk_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge, } static struct pci_bridge_emul_ops advk_pci_bridge_emul_ops = { + .read_base = advk_pci_bridge_emul_base_conf_read, + .write_base = advk_pci_bridge_emul_base_conf_write, .read_pcie = advk_pci_bridge_emul_pcie_conf_read, .write_pcie = advk_pci_bridge_emul_pcie_conf_write, };