linux-kernel - [RFC PATCH 3/3] PCI: iproc: Add dma reserve resources to host

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Date:   Wed, 12 Dec 2018 11:16:09 +0530
From:   Srinath Mannam <srinath.mannam@...adcom.com>
To:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Ray Jui <rjui@...adcom.com>
Cc:     bcm-kernel-feedback-list@...adcom.com, linux-pci@...r.kernel.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Srinath Mannam <srinath.mannam@...adcom.com>
Subject: [RFC PATCH 3/3] PCI: iproc: Add dma reserve resources to host

IPROC host has the limitation that it can use
only those address ranges given by dma-ranges
property as inbound address.
So that the memory address holes in dma-ranges
should be reserved to allocate as DMA address.

All such reserved addresses are created as resource
entries and add to dma_resv list of pci host bridge.

These dma reserve resources created by parsing
dma-ranges parameter.

Ex:
dma-ranges = < \
  0x43000000 0x00 0x80000000 0x00 0x80000000 0x00 0x80000000 \
  0x43000000 0x08 0x00000000 0x08 0x00000000 0x08 0x00000000 \
  0x43000000 0x80 0x00000000 0x80 0x00000000 0x40 0x00000000>

In the above example of dma-ranges, memory address from
0x0 - 0x80000000,
0x100000000 - 0x800000000,
0x1000000000 - 0x8000000000 and
0x10000000000 - 0xffffffffffffffff.
are not allowed to use as inbound addresses.
So that we need to add these address range to dma_resv
list to reserve their IOVA address ranges.

Signed-off-by: Srinath Mannam <srinath.mannam@...adcom.com>
---
 drivers/pci/controller/pcie-iproc.c | 49 +++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c
index 3160e93..43e465a 100644
--- a/drivers/pci/controller/pcie-iproc.c
+++ b/drivers/pci/controller/pcie-iproc.c
@@ -1154,25 +1154,74 @@ static int iproc_pcie_setup_ib(struct iproc_pcie *pcie,
 	return ret;
 }
 
+static int
+iproc_pcie_add_dma_resv_range(struct device *dev, struct list_head *resources,
+			      uint64_t start, uint64_t end)
+{
+	struct resource *res;
+
+	res = devm_kzalloc(dev, sizeof(struct resource), GFP_KERNEL);
+	if (!res)
+		return -ENOMEM;
+
+	res->start = (resource_size_t)start;
+	res->end = (resource_size_t)end;
+	pci_add_resource_offset(resources, res, 0);
+
+	return 0;
+}
+
 static int iproc_pcie_map_dma_ranges(struct iproc_pcie *pcie)
 {
+	struct pci_host_bridge *host = pci_host_bridge_from_priv(pcie);
 	struct of_pci_range range;
 	struct of_pci_range_parser parser;
 	int ret;
+	uint64_t start, end;
+	LIST_HEAD(resources);
 
 	/* Get the dma-ranges from DT */
 	ret = of_pci_dma_range_parser_init(&parser, pcie->dev->of_node);
 	if (ret)
 		return ret;
 
+	start = 0;
 	for_each_of_pci_range(&parser, &range) {
+		end = range.pci_addr;
+		/* dma-ranges list expected in sorted order */
+		if (end < start) {
+			ret = -EINVAL;
+			goto out;
+		}
 		/* Each range entry corresponds to an inbound mapping region */
 		ret = iproc_pcie_setup_ib(pcie, &range, IPROC_PCIE_IB_MAP_MEM);
 		if (ret)
 			return ret;
+
+		if (end - start) {
+			ret = iproc_pcie_add_dma_resv_range(pcie->dev,
+							    &resources,
+							    start, end);
+			if (ret)
+				goto out;
+		}
+		start = range.pci_addr + range.size;
 	}
 
+	end = ~0;
+	if (end - start) {
+		ret = iproc_pcie_add_dma_resv_range(pcie->dev, &resources,
+						    start, end);
+		if (ret)
+			goto out;
+	}
+
+	list_splice_init(&resources, &host->dma_resv);
+
 	return 0;
+out:
+	pci_free_resource_list(&resources);
+	return ret;
 }
 
 static int iproce_pcie_get_msi(struct iproc_pcie *pcie,
-- 
2.7.4