PCI: cadence: Use "dma-ranges" instead of "cdns,no-bar-match-nbits" property

Cadence PCIe core driver (host mode) uses "cdns,no-bar-match-nbits"
property to configure the number of bits passed through from PCIe
address to internal address in Inbound Address Translation register.
This only used the NO MATCH BAR.

However standard PCI dt-binding already defines "dma-ranges" to
describe the address ranges accessible by PCIe controller. Add support
in Cadence PCIe host driver to parse dma-ranges and configure the
inbound regions for BAR0, BAR1 and NO MATCH BAR. Cadence IP specifies
maximum size for BAR0 as 256GB, maximum size for BAR1 as 2 GB.

This adds support to take the next biggest region in "dma-ranges" and
find the smallest BAR that each of the regions fit in and if there is
no BAR big enough to hold the region, split the region to see if it can
be fitted using multiple BARs.

"dma-ranges" of J721E will be
dma-ranges = <0x02000000 0x0 0x0 0x0 0x0 0x10000 0x0>;
Since there is no BAR which can hold 2^48 size, NO_MATCH_BAR will be
used here.

Legacy device tree binding compatibility is maintained by retaining
support for "cdns,no-bar-match-nbits".

Link: https://lore.kernel.org/r/20200722110317.4744-2-kishon@ti.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>

1 files changed, 238 insertions, 14 deletions

diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c
index 8c2543f28ba0..2f599eb62bcf 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-host.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
@@ -4,6 +4,7 @@
 // Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
 
 #include <linux/kernel.h>
+#include <linux/list_sort.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
 #include <linux/platform_device.h>
@@ -11,6 +12,17 @@
 
 #include "pcie-cadence.h"
 
+static u64 bar_max_size[] = {
+	[RP_BAR0] = _ULL(128 * SZ_2G),
+	[RP_BAR1] = SZ_2G,
+	[RP_NO_BAR] = _BITULL(63),
+};
+
+static u8 bar_aperture_mask[] = {
+	[RP_BAR0] = 0x1F,
+	[RP_BAR1] = 0xF,
+};
+
 static void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
 				      int where)
 {
@@ -101,6 +113,218 @@ static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
 	return 0;
 }
 
+static int cdns_pcie_host_bar_ib_config(struct cdns_pcie_rc *rc,
+					enum cdns_pcie_rp_bar bar,
+					u64 cpu_addr, u64 size,
+					unsigned long flags)
+{
+	struct cdns_pcie *pcie = &rc->pcie;
+	u32 addr0, addr1, aperture, value;
+
+	if (!rc->avail_ib_bar[bar])
+		return -EBUSY;
+
+	rc->avail_ib_bar[bar] = false;
+
+	aperture = ilog2(size);
+	addr0 = CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS(aperture) |
+		(lower_32_bits(cpu_addr) & GENMASK(31, 8));
+	addr1 = upper_32_bits(cpu_addr);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR0(bar), addr0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR1(bar), addr1);
+
+	if (bar == RP_NO_BAR)
+		return 0;
+
+	value = cdns_pcie_readl(pcie, CDNS_PCIE_LM_RC_BAR_CFG);
+	value &= ~(LM_RC_BAR_CFG_CTRL_MEM_64BITS(bar) |
+		   LM_RC_BAR_CFG_CTRL_PREF_MEM_64BITS(bar) |
+		   LM_RC_BAR_CFG_CTRL_MEM_32BITS(bar) |
+		   LM_RC_BAR_CFG_CTRL_PREF_MEM_32BITS(bar) |
+		   LM_RC_BAR_CFG_APERTURE(bar, bar_aperture_mask[bar] + 2));
+	if (size + cpu_addr >= SZ_4G) {
+		if (!(flags & IORESOURCE_PREFETCH))
+			value |= LM_RC_BAR_CFG_CTRL_MEM_64BITS(bar);
+		value |= LM_RC_BAR_CFG_CTRL_PREF_MEM_64BITS(bar);
+	} else {
+		if (!(flags & IORESOURCE_PREFETCH))
+			value |= LM_RC_BAR_CFG_CTRL_MEM_32BITS(bar);
+		value |= LM_RC_BAR_CFG_CTRL_PREF_MEM_32BITS(bar);
+	}
+
+	value |= LM_RC_BAR_CFG_APERTURE(bar, aperture);
+	cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
+
+	return 0;
+}
+
+static enum cdns_pcie_rp_bar
+cdns_pcie_host_find_min_bar(struct cdns_pcie_rc *rc, u64 size)
+{
+	enum cdns_pcie_rp_bar bar, sel_bar;
+
+	sel_bar = RP_BAR_UNDEFINED;
+	for (bar = RP_BAR0; bar <= RP_NO_BAR; bar++) {
+		if (!rc->avail_ib_bar[bar])
+			continue;
+
+		if (size <= bar_max_size[bar]) {
+			if (sel_bar == RP_BAR_UNDEFINED) {
+				sel_bar = bar;
+				continue;
+			}
+
+			if (bar_max_size[bar] < bar_max_size[sel_bar])
+				sel_bar = bar;
+		}
+	}
+
+	return sel_bar;
+}
+
+static enum cdns_pcie_rp_bar
+cdns_pcie_host_find_max_bar(struct cdns_pcie_rc *rc, u64 size)
+{
+	enum cdns_pcie_rp_bar bar, sel_bar;
+
+	sel_bar = RP_BAR_UNDEFINED;
+	for (bar = RP_BAR0; bar <= RP_NO_BAR; bar++) {
+		if (!rc->avail_ib_bar[bar])
+			continue;
+
+		if (size >= bar_max_size[bar]) {
+			if (sel_bar == RP_BAR_UNDEFINED) {
+				sel_bar = bar;
+				continue;
+			}
+
+			if (bar_max_size[bar] > bar_max_size[sel_bar])
+				sel_bar = bar;
+		}
+	}
+
+	return sel_bar;
+}
+
+static int cdns_pcie_host_bar_config(struct cdns_pcie_rc *rc,
+				     struct resource_entry *entry)
+{
+	u64 cpu_addr, pci_addr, size, winsize;
+	struct cdns_pcie *pcie = &rc->pcie;
+	struct device *dev = pcie->dev;
+	enum cdns_pcie_rp_bar bar;
+	unsigned long flags;
+	int ret;
+
+	cpu_addr = entry->res->start;
+	pci_addr = entry->res->start - entry->offset;
+	flags = entry->res->flags;
+	size = resource_size(entry->res);
+
+	if (entry->offset) {
+		dev_err(dev, "PCI addr: %llx must be equal to CPU addr: %llx\n",
+			pci_addr, cpu_addr);
+		return -EINVAL;
+	}
+
+	while (size > 0) {
+		/*
+		 * Try to find a minimum BAR whose size is greater than
+		 * or equal to the remaining resource_entry size. This will
+		 * fail if the size of each of the available BARs is less than
+		 * the remaining resource_entry size.
+		 * If a minimum BAR is found, IB ATU will be configured and
+		 * exited.
+		 */
+		bar = cdns_pcie_host_find_min_bar(rc, size);
+		if (bar != RP_BAR_UNDEFINED) {
+			ret = cdns_pcie_host_bar_ib_config(rc, bar, cpu_addr,
+							   size, flags);
+			if (ret)
+				dev_err(dev, "IB BAR: %d config failed\n", bar);
+			return ret;
+		}
+
+		/*
+		 * If the control reaches here, it would mean the remaining
+		 * resource_entry size cannot be fitted in a single BAR. So we
+		 * find a maximum BAR whose size is less than or equal to the
+		 * remaining resource_entry size and split the resource entry
+		 * so that part of resource entry is fitted inside the maximum
+		 * BAR. The remaining size would be fitted during the next
+		 * iteration of the loop.
+		 * If a maximum BAR is not found, there is no way we can fit
+		 * this resource_entry, so we error out.
+		 */
+		bar = cdns_pcie_host_find_max_bar(rc, size);
+		if (bar == RP_BAR_UNDEFINED) {
+			dev_err(dev, "No free BAR to map cpu_addr %llx\n",
+				cpu_addr);
+			return -EINVAL;
+		}
+
+		winsize = bar_max_size[bar];
+		ret = cdns_pcie_host_bar_ib_config(rc, bar, cpu_addr, winsize,
+						   flags);
+		if (ret) {
+			dev_err(dev, "IB BAR: %d config failed\n", bar);
+			return ret;
+		}
+
+		size -= winsize;
+		cpu_addr += winsize;
+	}
+
+	return 0;
+}
+
+static int cdns_pcie_host_dma_ranges_cmp(void *priv, struct list_head *a, struct list_head *b)
+{
+	struct resource_entry *entry1, *entry2;
+
+        entry1 = container_of(a, struct resource_entry, node);
+        entry2 = container_of(b, struct resource_entry, node);
+
+        return resource_size(entry2->res) - resource_size(entry1->res);
+}
+
+static int cdns_pcie_host_map_dma_ranges(struct cdns_pcie_rc *rc)
+{
+	struct cdns_pcie *pcie = &rc->pcie;
+	struct device *dev = pcie->dev;
+	struct device_node *np = dev->of_node;
+	struct pci_host_bridge *bridge;
+	struct resource_entry *entry;
+	u32 no_bar_nbits = 32;
+	int err;
+
+	bridge = pci_host_bridge_from_priv(rc);
+	if (!bridge)
+		return -ENOMEM;
+
+	if (list_empty(&bridge->dma_ranges)) {
+		of_property_read_u32(np, "cdns,no-bar-match-nbits",
+				     &no_bar_nbits);
+		err = cdns_pcie_host_bar_ib_config(rc, RP_NO_BAR, 0x0,
+						   (u64)1 << no_bar_nbits, 0);
+		if (err)
+			dev_err(dev, "IB BAR: %d config failed\n", RP_NO_BAR);
+		return err;
+	}
+
+	list_sort(NULL, &bridge->dma_ranges, cdns_pcie_host_dma_ranges_cmp);
+
+	resource_list_for_each_entry(entry, &bridge->dma_ranges) {
+		err = cdns_pcie_host_bar_config(rc, entry);
+		if (err) {
+			dev_err(dev, "Fail to configure IB using dma-ranges\n");
+			return err;
+		}
+	}
+
+	return 0;
+}
+
 static int cdns_pcie_host_init_address_translation(struct cdns_pcie_rc *rc)
 {
 	struct cdns_pcie *pcie = &rc->pcie;
@@ -154,16 +378,9 @@ static int cdns_pcie_host_init_address_translation(struct cdns_pcie_rc *rc)
 		r++;
 	}
 
-	/*
-	 * Set Root Port no BAR match Inbound Translation registers:
-	 * needed for MSI and DMA.
-	 * Root Port BAR0 and BAR1 are disabled, hence no need to set their
-	 * inbound translation registers.
-	 */
-	addr0 = CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS(rc->no_bar_nbits);
-	addr1 = 0;
-	cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR0(RP_NO_BAR), addr0);
-	cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR1(RP_NO_BAR), addr1);
+	err = cdns_pcie_host_map_dma_ranges(rc);
+	if (err)
+		return err;
 
 	return 0;
 }
@@ -173,10 +390,16 @@ static int cdns_pcie_host_init(struct device *dev,
 			       struct cdns_pcie_rc *rc)
 {
 	struct resource *bus_range = NULL;
+	struct pci_host_bridge *bridge;
 	int err;
 
+	bridge = pci_host_bridge_from_priv(rc);
+	if (!bridge)
+		return -ENOMEM;
+
 	/* Parse our PCI ranges and request their resources */
-	err = pci_parse_request_of_pci_ranges(dev, resources, NULL, &bus_range);
+	err = pci_parse_request_of_pci_ranges(dev, resources,
+					      &bridge->dma_ranges, &bus_range);
 	if (err)
 		return err;
 
@@ -205,6 +428,7 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
 	struct device_node *np = dev->of_node;
 	struct pci_host_bridge *bridge;
 	struct list_head resources;
+	enum cdns_pcie_rp_bar bar;
 	struct cdns_pcie *pcie;
 	struct resource *res;
 	int ret;
@@ -216,9 +440,6 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
 	pcie = &rc->pcie;
 	pcie->is_rc = true;
 
-	rc->no_bar_nbits = 32;
-	of_property_read_u32(np, "cdns,no-bar-match-nbits", &rc->no_bar_nbits);
-
 	rc->vendor_id = 0xffff;
 	of_property_read_u32(np, "vendor-id", &rc->vendor_id);
 
@@ -248,6 +469,9 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
 
 	pcie->mem_res = res;
 
+	for (bar = RP_BAR0; bar <= RP_NO_BAR; bar++)
+		rc->avail_ib_bar[bar] = true;
+
 	ret = cdns_pcie_host_init(dev, &resources, rc);
 	if (ret)
 		goto err_init;