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From:   Zhangfei Gao <zhangfei.gao@linaro.org>
To:     Bjorn Helgaas <bhelgaas@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        jean-philippe <jean-philippe@linaro.org>,
        kenneth-lee-2012@foxmail.com, Wangzhou <wangzhou1@hisilicon.com>
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        Zhangfei Gao <zhangfei.gao@linaro.org>
Subject: [PATCH v4 1/3] PCI: PASID can be enabled without TLP prefix
Date:   Wed,  9 Jun 2021 11:36:39 +0800
Message-Id: <1623209801-1709-2-git-send-email-zhangfei.gao@linaro.org>
In-Reply-To: <1623209801-1709-1-git-send-email-zhangfei.gao@linaro.org>
References: <1623209801-1709-1-git-send-email-zhangfei.gao@linaro.org>
Precedence: bulk

A PASID-like feature is implemented on AMBA without using TLP prefixes
and these devices have PASID capability though not supporting TLP.
Adding a pasid_no_tlp bit for "PASID works without TLP prefixes" and
pci_enable_pasid() checks pasid_no_tlp as well as eetlp_prefix_path.

Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
---
 drivers/pci/ats.c   | 2 +-
 include/linux/pci.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index 6d7d649..c967ad6 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -376,7 +376,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features)
 	if (WARN_ON(pdev->pasid_enabled))
 		return -EBUSY;
 
-	if (!pdev->eetlp_prefix_path)
+	if (!pdev->eetlp_prefix_path && !pdev->pasid_no_tlp)
 		return -EINVAL;
 
 	if (!pasid)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c20211e..766dca1 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -388,6 +388,7 @@ struct pci_dev {
 					   supported from root to here */
 	u16		l1ss;		/* L1SS Capability pointer */
 #endif
+	unsigned int	pasid_no_tlp:1;		/* PASID works without TLP Prefix */
 	unsigned int	eetlp_prefix_path:1;	/* End-to-End TLP Prefix */
 
 	pci_channel_state_t error_state;	/* Current connectivity state */
-- 
2.7.4