[PATCH v2 1/2] NTB: epf: Allow arbitrary BAR mapping

[Jerome Brunet <jbrunet@baylibre.com>]

The NTB epf host driver assumes the BAR number associated with a memory
window is just incremented from the BAR number associated with MW1. This
seems to have been enough so far but this is not really how the endpoint
side work and the two could easily become mis-aligned.

ntb_epf_mw_to_bar() even assumes that the BAR number is the memory window
index + 2, which means the function only returns a proper result if BAR_2
is associated with MW1.

Instead, fully describe and allow arbitrary NTB BAR mapping.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/ntb/hw/epf/ntb_hw_epf.c | 105 +++++++++++++++++++++-------------------
 1 file changed, 54 insertions(+), 51 deletions(-)

diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c b/drivers/ntb/hw/epf/ntb_hw_epf.c
index 00f0e78f685bf7917b02dd8a52b5b35f68d5bb64..e8eb3adc6cecd2d52235a3f0b6b5a59ec58f1d73 100644
--- a/drivers/ntb/hw/epf/ntb_hw_epf.c
+++ b/drivers/ntb/hw/epf/ntb_hw_epf.c
@@ -49,6 +49,7 @@
 #define NTB_EPF_COMMAND_TIMEOUT	1000 /* 1 Sec */
 
 enum pci_barno {
+	NO_BAR = -1,
 	BAR_0,
 	BAR_1,
 	BAR_2,
@@ -57,16 +58,26 @@ enum pci_barno {
 	BAR_5,
 };
 
+enum epf_ntb_bar {
+	BAR_CONFIG,
+	BAR_PEER_SPAD,
+	BAR_DB,
+	BAR_MW1,
+	BAR_MW2,
+	BAR_MW3,
+	BAR_MW4,
+	NTB_BAR_NUM,
+};
+
+#define NTB_EPF_MAX_MW_COUNT	(NTB_BAR_NUM - BAR_MW1)
+
 struct ntb_epf_dev {
 	struct ntb_dev ntb;
 	struct device *dev;
 	/* Mutex to protect providing commands to NTB EPF */
 	struct mutex cmd_lock;
 
-	enum pci_barno ctrl_reg_bar;
-	enum pci_barno peer_spad_reg_bar;
-	enum pci_barno db_reg_bar;
-	enum pci_barno mw_bar;
+	const enum pci_barno *barno_map;
 
 	unsigned int mw_count;
 	unsigned int spad_count;
@@ -85,17 +96,6 @@ struct ntb_epf_dev {
 
 #define ntb_ndev(__ntb) container_of(__ntb, struct ntb_epf_dev, ntb)
 
-struct ntb_epf_data {
-	/* BAR that contains both control region and self spad region */
-	enum pci_barno ctrl_reg_bar;
-	/* BAR that contains peer spad region */
-	enum pci_barno peer_spad_reg_bar;
-	/* BAR that contains Doorbell region and Memory window '1' */
-	enum pci_barno db_reg_bar;
-	/* BAR that contains memory windows*/
-	enum pci_barno mw_bar;
-};
-
 static int ntb_epf_send_command(struct ntb_epf_dev *ndev, u32 command,
 				u32 argument)
 {
@@ -144,7 +144,7 @@ static int ntb_epf_mw_to_bar(struct ntb_epf_dev *ndev, int idx)
 		return -EINVAL;
 	}
 
-	return idx + 2;
+	return ndev->barno_map[BAR_MW1 + idx];
 }
 
 static int ntb_epf_mw_count(struct ntb_dev *ntb, int pidx)
@@ -413,7 +413,9 @@ static int ntb_epf_mw_set_trans(struct ntb_dev *ntb, int pidx, int idx,
 		return -EINVAL;
 	}
 
-	bar = idx + ndev->mw_bar;
+	bar = ntb_epf_mw_to_bar(ndev, idx);
+	if (bar < 0)
+		return bar;
 
 	mw_size = pci_resource_len(ntb->pdev, bar);
 
@@ -455,7 +457,9 @@ static int ntb_epf_peer_mw_get_addr(struct ntb_dev *ntb, int idx,
 	if (idx == 0)
 		offset = readl(ndev->ctrl_reg + NTB_EPF_MW1_OFFSET);
 
-	bar = idx + ndev->mw_bar;
+	bar = ntb_epf_mw_to_bar(ndev, idx);
+	if (bar < 0)
+		return bar;
 
 	if (base)
 		*base = pci_resource_start(ndev->ntb.pdev, bar) + offset;
@@ -557,8 +561,13 @@ static int ntb_epf_init_dev(struct ntb_epf_dev *ndev)
 	}
 
 	ndev->db_valid_mask = BIT_ULL(ndev->db_count) - 1;
-	ndev->mw_count = readl(ndev->ctrl_reg + NTB_EPF_MW_COUNT);
 	ndev->spad_count = readl(ndev->ctrl_reg + NTB_EPF_SPAD_COUNT);
+	ndev->mw_count = readl(ndev->ctrl_reg + NTB_EPF_MW_COUNT);
+
+	if (ndev->mw_count > NTB_EPF_MAX_MW_COUNT) {
+		dev_err(dev, "Unsupported MW count: %u\n", ndev->mw_count);
+		return -EINVAL;
+	}
 
 	return 0;
 }
@@ -596,14 +605,15 @@ static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
 		dev_warn(&pdev->dev, "Cannot DMA highmem\n");
 	}
 
-	ndev->ctrl_reg = pci_iomap(pdev, ndev->ctrl_reg_bar, 0);
+	ndev->ctrl_reg = pci_iomap(pdev, ndev->barno_map[BAR_CONFIG], 0);
 	if (!ndev->ctrl_reg) {
 		ret = -EIO;
 		goto err_pci_regions;
 	}
 
-	if (ndev->peer_spad_reg_bar) {
-		ndev->peer_spad_reg = pci_iomap(pdev, ndev->peer_spad_reg_bar, 0);
+	if (ndev->barno_map[BAR_PEER_SPAD] != ndev->barno_map[BAR_CONFIG]) {
+		ndev->peer_spad_reg = pci_iomap(pdev,
+						ndev->barno_map[BAR_PEER_SPAD], 0);
 		if (!ndev->peer_spad_reg) {
 			ret = -EIO;
 			goto err_pci_regions;
@@ -614,7 +624,7 @@ static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
 		ndev->peer_spad_reg = ndev->ctrl_reg + spad_off  + spad_sz;
 	}
 
-	ndev->db_reg = pci_iomap(pdev, ndev->db_reg_bar, 0);
+	ndev->db_reg = pci_iomap(pdev, ndev->barno_map[BAR_DB], 0);
 	if (!ndev->db_reg) {
 		ret = -EIO;
 		goto err_pci_regions;
@@ -659,12 +669,7 @@ static void ntb_epf_cleanup_isr(struct ntb_epf_dev *ndev)
 static int ntb_epf_pci_probe(struct pci_dev *pdev,
 			     const struct pci_device_id *id)
 {
-	enum pci_barno peer_spad_reg_bar = BAR_1;
-	enum pci_barno ctrl_reg_bar = BAR_0;
-	enum pci_barno db_reg_bar = BAR_2;
-	enum pci_barno mw_bar = BAR_2;
 	struct device *dev = &pdev->dev;
-	struct ntb_epf_data *data;
 	struct ntb_epf_dev *ndev;
 	int ret;
 
@@ -675,18 +680,10 @@ static int ntb_epf_pci_probe(struct pci_dev *pdev,
 	if (!ndev)
 		return -ENOMEM;
 
-	data = (struct ntb_epf_data *)id->driver_data;
-	if (data) {
-		peer_spad_reg_bar = data->peer_spad_reg_bar;
-		ctrl_reg_bar = data->ctrl_reg_bar;
-		db_reg_bar = data->db_reg_bar;
-		mw_bar = data->mw_bar;
-	}
+	ndev->barno_map = (const enum pci_barno *)id->driver_data;
+	if (!ndev->barno_map)
+		return -EINVAL;
 
-	ndev->peer_spad_reg_bar = peer_spad_reg_bar;
-	ndev->ctrl_reg_bar = ctrl_reg_bar;
-	ndev->db_reg_bar = db_reg_bar;
-	ndev->mw_bar = mw_bar;
 	ndev->dev = dev;
 
 	ntb_epf_init_struct(ndev, pdev);
@@ -730,30 +727,36 @@ static void ntb_epf_pci_remove(struct pci_dev *pdev)
 	ntb_epf_deinit_pci(ndev);
 }
 
-static const struct ntb_epf_data j721e_data = {
-	.ctrl_reg_bar = BAR_0,
-	.peer_spad_reg_bar = BAR_1,
-	.db_reg_bar = BAR_2,
-	.mw_bar = BAR_2,
+static const enum pci_barno j721e_map[NTB_BAR_NUM] = {
+	[BAR_CONFIG]	= BAR_0,
+	[BAR_PEER_SPAD]	= BAR_1,
+	[BAR_DB]	= BAR_2,
+	[BAR_MW1]	= BAR_2,
+	[BAR_MW2]	= BAR_3,
+	[BAR_MW3]	= BAR_4,
+	[BAR_MW4]	= BAR_5
 };
 
-static const struct ntb_epf_data mx8_data = {
-	.ctrl_reg_bar = BAR_0,
-	.peer_spad_reg_bar = BAR_0,
-	.db_reg_bar = BAR_2,
-	.mw_bar = BAR_4,
+static const enum pci_barno mx8_map[NTB_BAR_NUM] = {
+	[BAR_CONFIG]	= BAR_0,
+	[BAR_PEER_SPAD]	= BAR_0,
+	[BAR_DB]	= BAR_2,
+	[BAR_MW1]	= BAR_4,
+	[BAR_MW2]	= BAR_5,
+	[BAR_MW3]	= NO_BAR,
+	[BAR_MW4]	= NO_BAR
 };
 
 static const struct pci_device_id ntb_epf_pci_tbl[] = {
 	{
 		PCI_DEVICE(PCI_VENDOR_ID_TI, PCI_DEVICE_ID_TI_J721E),
 		.class = PCI_CLASS_MEMORY_RAM << 8, .class_mask = 0xffff00,
-		.driver_data = (kernel_ulong_t)&j721e_data,
+		.driver_data = (kernel_ulong_t)j721e_map,
 	},
 	{
 		PCI_DEVICE(PCI_VENDOR_ID_FREESCALE, 0x0809),
 		.class = PCI_CLASS_MEMORY_RAM << 8, .class_mask = 0xffff00,
-		.driver_data = (kernel_ulong_t)&mx8_data,
+		.driver_data = (kernel_ulong_t)mx8_map,
 	},
 	{ },
 };

-- 
2.47.2