PCI: PASID can be enabled without TLP prefix

driver inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I472UK?from=project-issue

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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: NBjorn Helgaas <helgaas@kernel.org>
Signed-off-by: NZhangfei Gao <zhangfei.gao@linaro.org>
Reviewed-by: NHao Fang <fanghao11@huawei.com>
Reviewed-by: NMingqiang Ling <lingmingqiang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/pci/ats.c

@@ -380,7 +380,7 @@ 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)

include/linux/pci.h

@@ -382,6 +382,7 @@ struct pci_dev {
 					   supported from root to here */
 	int		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 */