linux-kernel - [PATCH v4 05/10] cxl/pci: Make more use of cxl_register

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Date:   Sat, 09 Oct 2021 13:51:13 -0700
From:   Dan Williams <dan.j.williams@...el.com>
To:     linux-cxl@...r.kernel.org
Cc:     Ben Widawsky <ben.widawsky@...el.com>,
        kernel test robot <lkp@...el.com>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 05/10] cxl/pci: Make more use of cxl_register_map

From: Ben Widawsky <ben.widawsky@...el.com>

The structure exists to pass around information about register mapping.
Use it for passing @barno and @block_offset, and eliminate duplicate
local variables.

The helpers that use @map do not care about @cxlm, so just pass them a
pdev instead.

Signed-off-by: Ben Widawsky <ben.widawsky@...el.com>
Reported-by: kernel test robot <lkp@...el.com>
[djbw: separate @base conversion]
[djbw: reorder before cxl_pci_setup_regs() refactor to improver readability]
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
Changes since v3:
- Fix a 0day report about printing a resource_size_t

 drivers/cxl/pci.c |   55 ++++++++++++++++++++++-------------------------------
 1 file changed, 23 insertions(+), 32 deletions(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 21dd10a77eb3..f1de236ccd13 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -306,12 +306,13 @@ static int cxl_pci_setup_mailbox(struct cxl_mem *cxlm)
 	return 0;
 }
 
-static void __iomem *cxl_pci_map_regblock(struct cxl_mem *cxlm,
-					  u8 bar, u64 offset)
+static void __iomem *cxl_pci_map_regblock(struct pci_dev *pdev,
+					  struct cxl_register_map *map)
 {
 	void __iomem *addr;
-	struct device *dev = cxlm->dev;
-	struct pci_dev *pdev = to_pci_dev(dev);
+	int bar = map->barno;
+	struct device *dev = &pdev->dev;
+	resource_size_t offset = map->block_offset;
 
 	/* Basic sanity check that BAR is big enough */
 	if (pci_resource_len(pdev, bar) < offset) {
@@ -326,15 +327,15 @@ static void __iomem *cxl_pci_map_regblock(struct cxl_mem *cxlm,
 		return addr;
 	}
 
-	dev_dbg(dev, "Mapped CXL Memory Device resource bar %u @ %#llx\n",
-		bar, offset);
+	dev_dbg(dev, "Mapped CXL Memory Device resource bar %u @ %pa\n",
+		bar, &offset);
 
 	return addr;
 }
 
-static void cxl_pci_unmap_regblock(struct cxl_mem *cxlm, void __iomem *base)
+static void cxl_pci_unmap_regblock(struct pci_dev *pdev, void __iomem *base)
 {
-	pci_iounmap(to_pci_dev(cxlm->dev), base);
+	pci_iounmap(pdev, base);
 }
 
 static int cxl_pci_dvsec(struct pci_dev *pdev, int dvsec)
@@ -360,12 +361,12 @@ static int cxl_pci_dvsec(struct pci_dev *pdev, int dvsec)
 	return 0;
 }
 
-static int cxl_probe_regs(struct cxl_mem *cxlm, void __iomem *base,
+static int cxl_probe_regs(struct pci_dev *pdev, void __iomem *base,
 			  struct cxl_register_map *map)
 {
 	struct cxl_component_reg_map *comp_map;
 	struct cxl_device_reg_map *dev_map;
-	struct device *dev = cxlm->dev;
+	struct device *dev = &pdev->dev;
 
 	switch (map->reg_type) {
 	case CXL_REGLOC_RBI_COMPONENT:
@@ -420,12 +421,13 @@ static int cxl_map_regs(struct cxl_mem *cxlm, struct cxl_register_map *map)
 	return 0;
 }
 
-static void cxl_decode_register_block(u32 reg_lo, u32 reg_hi,
-				      u8 *bar, u64 *offset, u8 *reg_type)
+static void cxl_decode_regblock(u32 reg_lo, u32 reg_hi,
+				struct cxl_register_map *map)
 {
-	*offset = ((u64)reg_hi << 32) | (reg_lo & CXL_REGLOC_ADDR_MASK);
-	*bar = FIELD_GET(CXL_REGLOC_BIR_MASK, reg_lo);
-	*reg_type = FIELD_GET(CXL_REGLOC_RBI_MASK, reg_lo);
+	map->block_offset =
+		((u64)reg_hi << 32) | (reg_lo & CXL_REGLOC_ADDR_MASK);
+	map->barno = FIELD_GET(CXL_REGLOC_BIR_MASK, reg_lo);
+	map->reg_type = FIELD_GET(CXL_REGLOC_RBI_MASK, reg_lo);
 }
 
 /**
@@ -462,34 +464,23 @@ static int cxl_pci_setup_regs(struct cxl_mem *cxlm)
 
 	for (i = 0, n_maps = 0; i < regblocks; i++, regloc += 8) {
 		u32 reg_lo, reg_hi;
-		u8 reg_type;
-		u64 offset;
-		u8 bar;
 
 		pci_read_config_dword(pdev, regloc, &reg_lo);
 		pci_read_config_dword(pdev, regloc + 4, &reg_hi);
 
-		cxl_decode_register_block(reg_lo, reg_hi, &bar, &offset,
-					  &reg_type);
+		map = &maps[n_maps];
+		cxl_decode_regblock(reg_lo, reg_hi, map);
 
 		/* Ignore unknown register block types */
-		if (reg_type > CXL_REGLOC_RBI_MEMDEV)
+		if (map->reg_type > CXL_REGLOC_RBI_MEMDEV)
 			continue;
 
-		base = cxl_pci_map_regblock(cxlm, bar, offset);
+		base = cxl_pci_map_regblock(pdev, map);
 		if (!base)
 			return -ENOMEM;
 
-		map = &maps[n_maps];
-		map->barno = bar;
-		map->block_offset = offset;
-		map->reg_type = reg_type;
-
-		ret = cxl_probe_regs(cxlm, base + offset, map);
-
-		/* Always unmap the regblock regardless of probe success */
-		cxl_pci_unmap_regblock(cxlm, base);
-
+		ret = cxl_probe_regs(pdev, base + map->block_offset, map);
+		cxl_pci_unmap_regblock(pdev, base);
 		if (ret)
 			return ret;