[RFC,v2,5/6] dmaengine: Add Synopsys eDMA IP PCIe glue-logic

From: Gustavo Pimentel <hidden>
Date: 2018-12-17 17:19:37
Also in: linux-pci
Subsystem: designware edma core ip driver, dma generic offload engine subsystem, the rest · Maintainers: Manivannan Sadhasivam, Vinod Koul, Linus Torvalds

Synopsys eDMA IP is normally distributed along with Synopsys PCIe
EndPoint IP (depends of the use and licensing agreement).

This IP requires some basic configurations, such as:
 - eDMA registers BAR
 - eDMA registers offset
 - eDMA linked list BAR
 - eDMA linked list offset
 - eDMA linked list size
 - eDMA version
 - eDMA mode

As a working example, PCIe glue-logic will attach to a Synopsys PCIe
EndPoint IP prototype kit (Vendor ID = 0x16c3, Device ID = 0xedda),
which has built-in an eDMA IP with this default configuration:
 - eDMA registers BAR = 0
 - eDMA registers offset = 0x1000 (4 Kbytes)
 - eDMA linked list BAR = 2
 - eDMA linked list offset = 0x0 (0 Kbytes)
 - eDMA linked list size = 0x20000 (128 Kbytes)
 - eDMA version = 0
 - eDMA mode = EDMA_MODE_UNROLL

This driver can be compile as built-in or external module in kernel.

To enable this driver just select DW_EDMA_PCIE option in kernel
configuration, however it requires and selects automatically DW_EDMA
option too.

Changes:
RFC v1->RFC v2:
 - Replace comments // (C99 style) by /**/
 - Merge two pcim_iomap_regions() calls into just one call
 - Remove pci_try_set_mwi() call
 - Replace some dev_info() by dev_dbg() to reduce *noise*
 - Remove pci_name(pdev) call after being call dw_edma_remove()
 - Remove all power management support
 - Fix the headers of the .c and .h files according to the most recent
   convention
 - Fix errors and checks pointed out by checkpatch with --strict option
 - Replace patch small description tag from dma by dmaengine

Signed-off-by: Gustavo Pimentel <redacted>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Dan Williams <redacted>
Cc: Eugeniy Paltsev <redacted>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Russell King <redacted>
Cc: Niklas Cassel <redacted>
Cc: Lorenzo Pieralisi <redacted>
Cc: Joao Pinto <redacted>
Cc: Jose Abreu <jose.abreu@synopsys.com>
Cc: Luis Oliveira <redacted>
Cc: Vitor Soares <redacted>
Cc: Nelson Costa <redacted>
Cc: Pedro Sousa <pedrom.sousa@synopsys.com>
---
 drivers/dma/dw-edma/Kconfig        |   9 ++
 drivers/dma/dw-edma/Makefile       |   1 +
 drivers/dma/dw-edma/dw-edma-pcie.c | 258 +++++++++++++++++++++++++++++++++++++
 3 files changed, 268 insertions(+)
 create mode 100644 drivers/dma/dw-edma/dw-edma-pcie.c
diff --git a/drivers/dma/dw-edma/Kconfig b/drivers/dma/dw-edma/Kconfig
index 3016bed..c0838ce 100644
--- a/drivers/dma/dw-edma/Kconfig
+++ b/drivers/dma/dw-edma/Kconfig
@@ -7,3 +7,12 @@ config DW_EDMA
 	help
 	  Support the Synopsys DesignWare eDMA controller, normally
 	  implemented on endpoints SoCs.
+
+config DW_EDMA_PCIE
+	tristate "Synopsys DesignWare eDMA PCIe driver"
+	depends on PCI && PCI_MSI
+	select DW_EDMA
+	help
+	  Provides a glue-logic between the Synopsys DesignWare
+	  eDMA controller and an endpoint PCIe device. This also serves
+	  as a reference design to whom desires to use this IP.
diff --git a/drivers/dma/dw-edma/Makefile b/drivers/dma/dw-edma/Makefile
index 0c53033..8d45c0d 100644
--- a/drivers/dma/dw-edma/Makefile
+++ b/drivers/dma/dw-edma/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_DW_EDMA)		+= dw-edma.o
 dw-edma-$(CONFIG_DEBUG_FS)	:= dw-edma-v0-debugfs.o
 dw-edma-objs			:= dw-edma-core.o \
 					dw-edma-v0-core.o $(dw-edma-y)
+obj-$(CONFIG_DW_EDMA_PCIE)	+= dw-edma-pcie.o
diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
new file mode 100644
index 0000000..6305768
--- /dev/null
+++ b/drivers/dma/dw-edma/dw-edma-pcie.c
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 Synopsys, Inc. and/or its affiliates.
+ * Synopsys DesignWare eDMA PCIe driver
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/device.h>
+#include <linux/dma/edma.h>
+
+#include "dw-edma-core.h"
+
+enum dw_edma_pcie_bar {
+	BAR_0,
+	BAR_1,
+	BAR_2,
+	BAR_3,
+	BAR_4,
+	BAR_5
+};
+
+struct dw_edma_pcie_data {
+	enum dw_edma_pcie_bar		regs_bar;
+	u64				regs_off;
+	enum dw_edma_pcie_bar		ll_bar;
+	u64				ll_off;
+	size_t				ll_sz;
+	u32				version;
+	enum dw_edma_mode		mode;
+};
+
+static const struct dw_edma_pcie_data snps_edda_data = {
+	/* eDMA registers location */
+	.regs_bar			= BAR_0,
+	.regs_off			= 0x1000,	/*   4 KBytes */
+	/* eDMA memory linked list location */
+	.ll_bar				= BAR_2,
+	.ll_off				= 0,		/*   0 KBytes */
+	.ll_sz				= 0x20000,	/* 128 KBytes */
+	/* Other */
+	.version			= 0,
+	.mode				= EDMA_MODE_UNROLL,
+};
+
+static int dw_edma_pcie_probe(struct pci_dev *pdev,
+			      const struct pci_device_id *pid)
+{
+	const struct dw_edma_pcie_data *pdata = (void *)pid->driver_data;
+	struct device *dev = &pdev->dev;
+	struct dw_edma_chip *chip;
+	struct dw_edma *dw;
+	void __iomem *reg;
+	int err, irq = -1;
+	u32 addr_hi, addr_lo;
+	u16 flags;
+	u8 cap_off;
+
+	if (!pdata) {
+		dev_err(dev, "%s missing data struture\n",
+			pci_name(pdev));
+		return -EFAULT;
+	}
+
+	err = pcim_enable_device(pdev);
+	if (err) {
+		dev_err(dev, "%s enabling device failed\n",
+			pci_name(pdev));
+		return err;
+	}
+
+	err = pcim_iomap_regions(pdev,
+				 BIT(pdata->regs_bar) | BIT(pdata->ll_bar),
+				 pci_name(pdev));
+	if (err) {
+		dev_err(dev, "%s eDMA BAR I/O remapping failed\n",
+			pci_name(pdev));
+		return err;
+	}
+
+	pci_set_master(pdev);
+
+	err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+	if (err) {
+		dev_err(dev, "%s DMA mask set failed\n",
+			pci_name(pdev));
+		return err;
+	}
+
+	err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
+	if (err) {
+		dev_err(dev, "%s consistent DMA mask set failed\n",
+			pci_name(pdev));
+		return err;
+	}
+
+	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	dw = devm_kzalloc(&pdev->dev, sizeof(*dw), GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+
+	irq = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI | PCI_IRQ_MSIX);
+	if (irq < 0) {
+		dev_err(dev, "%s failed to alloc IRQ vector\n",
+			pci_name(pdev));
+		return -EPERM;
+	}
+
+	chip->dw = dw;
+	chip->dev = dev;
+	chip->id = pdev->devfn;
+	chip->irq = pdev->irq;
+
+	dw->regs = pcim_iomap_table(pdev)[pdata->regs_bar];
+	dw->regs += pdata->regs_off;
+
+	dw->va_ll = pcim_iomap_table(pdev)[pdata->ll_bar];
+	dw->va_ll += pdata->ll_off;
+	dw->pa_ll = pdev->resource[pdata->ll_bar].start;
+	dw->pa_ll += pdata->ll_off;
+	dw->ll_sz = pdata->ll_sz;
+
+	dw->msi_addr = 0;
+	dw->msi_data = 0;
+
+	dw->version = pdata->version;
+	dw->mode = pdata->mode;
+
+	dev_dbg(dev, "Version:\t%u\n", dw->version);
+
+	dev_dbg(dev, "Mode:\t%s\n",
+		dw->mode == EDMA_MODE_LEGACY ? "Legacy" : "Unroll");
+
+	dev_dbg(dev, "Registers:\tBAR=%u, off=0x%.16llx B, addr=0x%.8lx\n",
+		pdata->regs_bar, pdata->regs_off,
+		(unsigned long)dw->regs);
+
+	dev_dbg(dev, "L. List:\tBAR=%u, off=0x%.16llx B, sz=0x%.8x B, vaddr=0x%.8lx, paddr=0x%.8lx",
+		pdata->ll_bar, pdata->ll_off, pdata->ll_sz,
+		(unsigned long)dw->va_ll,
+		(unsigned long)dw->pa_ll);
+
+	if (pdev->msi_cap && pdev->msi_enabled) {
+		cap_off = pdev->msi_cap + PCI_MSI_FLAGS;
+		pci_read_config_word(pdev, cap_off, &flags);
+		if (flags & PCI_MSI_FLAGS_ENABLE) {
+			cap_off = pdev->msi_cap + PCI_MSI_ADDRESS_LO;
+			pci_read_config_dword(pdev, cap_off, &addr_lo);
+
+			if (flags & PCI_MSI_FLAGS_64BIT) {
+				cap_off = pdev->msi_cap + PCI_MSI_ADDRESS_HI;
+				pci_read_config_dword(pdev, cap_off, &addr_hi);
+				cap_off = pdev->msi_cap + PCI_MSI_DATA_64;
+			} else {
+				addr_hi = 0;
+				cap_off = pdev->msi_cap + PCI_MSI_DATA_32;
+			}
+
+			dw->msi_addr = addr_hi;
+			dw->msi_addr <<= 32;
+			dw->msi_addr |= addr_lo;
+
+			pci_read_config_dword(pdev, cap_off, &dw->msi_data);
+			dw->msi_data &= 0xffff;
+
+			dev_dbg(dev, "MSI:\t\taddr=0x%.16llx, data=0x%.8x, nr=%d\n",
+				dw->msi_addr, dw->msi_data, pdev->irq);
+		}
+	}
+
+	if (pdev->msix_cap && pdev->msix_enabled) {
+		u32 offset;
+		u8 bir;
+
+		cap_off = pdev->msix_cap + PCI_MSIX_FLAGS;
+		pci_read_config_word(pdev, cap_off, &flags);
+
+		if (flags & PCI_MSIX_FLAGS_ENABLE) {
+			cap_off = pdev->msix_cap + PCI_MSIX_TABLE;
+			pci_read_config_dword(pdev, cap_off, &offset);
+
+			bir = offset & PCI_MSIX_TABLE_BIR;
+			offset &= PCI_MSIX_TABLE_OFFSET;
+
+			reg = pcim_iomap_table(pdev)[bir];
+			reg += offset;
+
+			addr_lo = readl(reg + PCI_MSIX_ENTRY_LOWER_ADDR);
+			addr_hi = readl(reg + PCI_MSIX_ENTRY_UPPER_ADDR);
+			dw->msi_addr = addr_hi;
+			dw->msi_addr <<= 32;
+			dw->msi_addr |= addr_lo;
+
+			dw->msi_data = readl(reg + PCI_MSIX_ENTRY_DATA);
+
+			dev_dbg(dev,
+				"MSI-X:\taddr=0x%.16llx, data=0x%.8x, nr=%d\n",
+				dw->msi_addr, dw->msi_data, pdev->irq);
+		}
+	}
+
+	if (!pdev->msi_enabled && !pdev->msix_enabled) {
+		dev_err(dev, "%s enable interrupt failed\n",
+			pci_name(pdev));
+		return -EPERM;
+	}
+
+	err = dw_edma_probe(chip);
+	if (err) {
+		dev_err(dev, "%s eDMA probe failed\n",
+			pci_name(pdev));
+		return err;
+	}
+
+	pci_set_drvdata(pdev, chip);
+
+	dev_info(dev, "DesignWare eDMA PCIe driver loaded completely\n");
+
+	return 0;
+}
+
+static void dw_edma_pcie_remove(struct pci_dev *pdev)
+{
+	struct dw_edma_chip *chip = pci_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+	int err;
+
+	err = dw_edma_remove(chip);
+	if (err)
+		dev_warn(dev, "can't remove device properly: %d\n", err);
+
+	pci_free_irq_vectors(pdev);
+
+	dev_info(dev, "DesignWare eDMA PCIe driver unloaded completely\n");
+}
+
+static const struct pci_device_id dw_edma_pcie_id_table[] = {
+	{ PCI_DEVICE_DATA(SYNOPSYS, EDDA, &snps_edda_data) },
+	{ }
+};
+MODULE_DEVICE_TABLE(pci, dw_edma_pcie_id_table);
+
+static struct pci_driver dw_edma_pcie_driver = {
+	.name		= "dw-edma-pcie",
+	.id_table	= dw_edma_pcie_id_table,
+	.probe		= dw_edma_pcie_probe,
+	.remove		= dw_edma_pcie_remove,
+};
+
+module_pci_driver(dw_edma_pcie_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Synopsys DesignWare eDMA PCIe driver");
+MODULE_AUTHOR("Gustavo Pimentel <gustavo.pimentel@synopsys.com>");
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