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From:   "Jiang, Dave" <dave.jiang@intel.com>
To:     Kishon Vijay Abraham I <kishon@ti.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Arnd Bergmann <arnd@arndb.de>, Jon Mason <jdmason@kudzu.us>,
        Allen Hubbe <allenbh@gmail.com>,
        Tom Joseph <tjoseph@cadence.com>, Rob Herring <robh@kernel.org>
CC:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-ntb@googlegroups.com" <linux-ntb@googlegroups.com>
Subject: RE: [PATCH v8 15/18] NTB: Add support for EPF PCI-Express
 Non-Transparent Bridge
Thread-Topic: [PATCH v8 15/18] NTB: Add support for EPF PCI-Express
 Non-Transparent Bridge
Thread-Index: AQHWuEC81UR/T28UFE+kPrdLACt5ianr8lFA
Date:   Mon, 7 Dec 2020 15:57:56 +0000
Message-ID: <b63d37bccd4f4afc833fd0b9078c3b89@intel.com>
References: <20201111153559.19050-1-kishon@ti.com>
 <20201111153559.19050-16-kishon@ti.com>
In-Reply-To: <20201111153559.19050-16-kishon@ti.com>
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> -----Original Message-----
> From: Kishon Vijay Abraham I <kishon@ti.com>
> Sent: Wednesday, November 11, 2020 8:36 AM
> To: Bjorn Helgaas <bhelgaas@google.com>; Jonathan Corbet
> <corbet@lwn.net>; Kishon Vijay Abraham I <kishon@ti.com>; Lorenzo
> Pieralisi <lorenzo.pieralisi@arm.com>; Arnd Bergmann <arnd@arndb.de>;
> Jon Mason <jdmason@kudzu.us>; Jiang, Dave <dave.jiang@intel.com>;
> Allen Hubbe <allenbh@gmail.com>; Tom Joseph <tjoseph@cadence.com>;
> Rob Herring <robh@kernel.org>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; linux-
> pci@vger.kernel.org; linux-doc@vger.kernel.org; linux-
> kernel@vger.kernel.org; linux-ntb@googlegroups.com
> Subject: [PATCH v8 15/18] NTB: Add support for EPF PCI-Express Non-
> Transparent Bridge
> 
> Add support for EPF PCI-Express Non-Transparent Bridge (NTB) device.
> This driver is platform independent and could be used by any platform which
> have multiple PCIe endpoint instances configured using the pci-epf-ntb
> driver. The driver connnects to the standard NTB sub-system interface. The
> EPF NTB device has configurable number of memory windows (Max 4),
> configurable number of doorbell (Max 32), and configurable number of
> scratch-pad registers.
> 
> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
> ---
>  drivers/ntb/hw/Kconfig          |   1 +
>  drivers/ntb/hw/Makefile         |   1 +
>  drivers/ntb/hw/epf/Kconfig      |   6 +
>  drivers/ntb/hw/epf/Makefile     |   1 +
>  drivers/ntb/hw/epf/ntb_hw_epf.c | 755
> ++++++++++++++++++++++++++++++++
>  5 files changed, 764 insertions(+)
>  create mode 100644 drivers/ntb/hw/epf/Kconfig  create mode 100644
> drivers/ntb/hw/epf/Makefile  create mode 100644
> drivers/ntb/hw/epf/ntb_hw_epf.c
> 
> diff --git a/drivers/ntb/hw/Kconfig b/drivers/ntb/hw/Kconfig index
> e77c587060ff..c325be526b80 100644
> --- a/drivers/ntb/hw/Kconfig
> +++ b/drivers/ntb/hw/Kconfig
> @@ -2,4 +2,5 @@
>  source "drivers/ntb/hw/amd/Kconfig"
>  source "drivers/ntb/hw/idt/Kconfig"
>  source "drivers/ntb/hw/intel/Kconfig"
> +source "drivers/ntb/hw/epf/Kconfig"
>  source "drivers/ntb/hw/mscc/Kconfig"
> diff --git a/drivers/ntb/hw/Makefile b/drivers/ntb/hw/Makefile index
> 4714d6238845..223ca592b5f9 100644
> --- a/drivers/ntb/hw/Makefile
> +++ b/drivers/ntb/hw/Makefile
> @@ -2,4 +2,5 @@
>  obj-$(CONFIG_NTB_AMD)	+= amd/
>  obj-$(CONFIG_NTB_IDT)	+= idt/
>  obj-$(CONFIG_NTB_INTEL)	+= intel/
> +obj-$(CONFIG_NTB_EPF)	+= epf/
>  obj-$(CONFIG_NTB_SWITCHTEC) += mscc/
> diff --git a/drivers/ntb/hw/epf/Kconfig b/drivers/ntb/hw/epf/Kconfig new
> file mode 100644 index 000000000000..6197d1aab344
> --- /dev/null
> +++ b/drivers/ntb/hw/epf/Kconfig
> @@ -0,0 +1,6 @@
> +config NTB_EPF
> +	tristate "Generic EPF Non-Transparent Bridge support"
> +	depends on m
> +	help
> +	  This driver supports EPF NTB on configurable endpoint.
> +	  If unsure, say N.
> diff --git a/drivers/ntb/hw/epf/Makefile b/drivers/ntb/hw/epf/Makefile
> new file mode 100644 index 000000000000..2f560a422bc6
> --- /dev/null
> +++ b/drivers/ntb/hw/epf/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_NTB_EPF) += ntb_hw_epf.o
> diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c
> b/drivers/ntb/hw/epf/ntb_hw_epf.c new file mode 100644 index
> 000000000000..3855bb0ecacd
> --- /dev/null
> +++ b/drivers/ntb/hw/epf/ntb_hw_epf.c
> @@ -0,0 +1,755 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/**
> + * Host side endpoint driver to implement Non-Transparent Bridge
> +functionality
> + *
> + * Copyright (C) 2020 Texas Instruments
> + * Author: Kishon Vijay Abraham I <kishon@ti.com>  */
> +
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/slab.h>
> +#include <linux/ntb.h>
> +
> +#define NTB_EPF_COMMAND		0x0
> +#define CMD_CONFIGURE_DOORBELL	1
> +#define CMD_TEARDOWN_DOORBELL	2
> +#define CMD_CONFIGURE_MW	3
> +#define CMD_TEARDOWN_MW		4
> +#define CMD_LINK_UP		5
> +#define CMD_LINK_DOWN		6
> +
> +#define NTB_EPF_ARGUMENT	0x4
> +#define MSIX_ENABLE		BIT(16)
> +
> +#define NTB_EPF_CMD_STATUS	0x8
> +#define COMMAND_STATUS_OK	1
> +#define COMMAND_STATUS_ERROR	2
> +
> +#define NTB_EPF_LINK_STATUS	0x0A
> +#define LINK_STATUS_UP		BIT(0)
> +
> +#define NTB_EPF_TOPOLOGY	0x0C
> +#define NTB_EPF_LOWER_ADDR	0x10
> +#define NTB_EPF_UPPER_ADDR	0x14
> +#define NTB_EPF_LOWER_SIZE	0x18
> +#define NTB_EPF_UPPER_SIZE	0x1C
> +#define NTB_EPF_MW_COUNT	0x20
> +#define NTB_EPF_MW1_OFFSET	0x24
> +#define NTB_EPF_SPAD_OFFSET	0x28
> +#define NTB_EPF_SPAD_COUNT	0x2C
> +#define NTB_EPF_DB_ENTRY_SIZE	0x30
> +#define NTB_EPF_DB_DATA(n)	(0x34 + (n) * 4)
> +#define NTB_EPF_DB_OFFSET(n)	(0xB4 + (n) * 4)
> +
> +#define NTB_EPF_MIN_DB_COUNT	3
> +#define NTB_EPF_MAX_DB_COUNT	31
> +#define NTB_EPF_MW_OFFSET	2
> +
> +#define NTB_EPF_COMMAND_TIMEOUT	1000 /* 1 Sec */
> +
> +enum pci_barno {
> +	BAR_0,
> +	BAR_1,
> +	BAR_2,
> +	BAR_3,
> +	BAR_4,
> +	BAR_5,
> +};
> +
> +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;
> +
> +	unsigned int mw_count;
> +	unsigned int spad_count;
> +	unsigned int db_count;
> +
> +	void __iomem *ctrl_reg;
> +	void __iomem *db_reg;
> +	void __iomem *peer_spad_reg;
> +
> +	unsigned int self_spad;
> +	unsigned int peer_spad;
> +
> +	int db_val;
> +	u64 db_valid_mask;
> +};
> +
> +#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;
> +};
> +
> +static int ntb_epf_send_command(struct ntb_epf_dev *ndev, u32
> command,
> +				u32 argument)
> +{
> +	ktime_t timeout;
> +	bool timedout;
> +	int ret = 0;
> +	u32 status;
> +
> +	mutex_lock(&ndev->cmd_lock);
> +	writel(argument, ndev->ctrl_reg + NTB_EPF_ARGUMENT);
> +	writel(command, ndev->ctrl_reg + NTB_EPF_COMMAND);
> +
> +	timeout = ktime_add_ms(ktime_get(),
> NTB_EPF_COMMAND_TIMEOUT);
> +	while (1) {
> +		timedout = ktime_after(ktime_get(), timeout);
> +		status = readw(ndev->ctrl_reg + NTB_EPF_CMD_STATUS);
> +
> +		if (status == COMMAND_STATUS_ERROR) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +
> +		if (status == COMMAND_STATUS_OK)
> +			break;
> +
> +		if (WARN_ON(timedout)) {
> +			ret = -ETIMEDOUT;
> +			break;
> +		}
> +
> +		usleep_range(5, 10);
> +	}
> +
> +	writew(0, ndev->ctrl_reg + NTB_EPF_CMD_STATUS);
> +	mutex_unlock(&ndev->cmd_lock);
> +
> +	return ret;
> +}
> +
> +static int ntb_epf_mw_to_bar(struct ntb_epf_dev *ndev, int idx) {
> +	struct device *dev = ndev->dev;
> +
> +	if (idx < 0 || idx > ndev->mw_count) {
> +		dev_err(dev, "Unsupported Memory Window index %d\n",
> idx);
> +		return -EINVAL;
> +	}
> +
> +	return idx + 2;
> +}
> +
> +static int ntb_epf_mw_count(struct ntb_dev *ntb, int pidx) {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +
> +	if (pidx != NTB_DEF_PEER_IDX) {
> +		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
> +		return -EINVAL;
> +	}
> +
> +	return ndev->mw_count;
> +}
> +
> +static int ntb_epf_mw_get_align(struct ntb_dev *ntb, int pidx, int idx,
> +				resource_size_t *addr_align,
> +				resource_size_t *size_align,
> +				resource_size_t *size_max)
> +{
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +	int bar;
> +
> +	if (pidx != NTB_DEF_PEER_IDX) {
> +		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
> +		return -EINVAL;
> +	}
> +
> +	bar = ntb_epf_mw_to_bar(ndev, idx);
> +	if (bar < 0)
> +		return bar;
> +
> +	if (addr_align)
> +		*addr_align = SZ_4K;
> +
> +	if (size_align)
> +		*size_align = 1;
> +
> +	if (size_max)
> +		*size_max = pci_resource_len(ndev->ntb.pdev, bar);
> +
> +	return 0;
> +}
> +
> +static u64 ntb_epf_link_is_up(struct ntb_dev *ntb,
> +			      enum ntb_speed *speed,
> +			      enum ntb_width *width)
> +{
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	u32 status;
> +
> +	status = readw(ndev->ctrl_reg + NTB_EPF_LINK_STATUS);
> +
> +	return status & LINK_STATUS_UP;
> +}
> +
> +static u32 ntb_epf_spad_read(struct ntb_dev *ntb, int idx) {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +	u32 offset;
> +
> +	if (idx < 0 || idx >= ndev->spad_count) {
> +		dev_err(dev, "READ: Invalid ScratchPad Index %d\n", idx);
> +		return 0;
> +	}
> +
> +	offset = readl(ndev->ctrl_reg + NTB_EPF_SPAD_OFFSET);
> +	offset += (idx << 2);
> +
> +	return readl(ndev->ctrl_reg + offset); }
> +
> +static int ntb_epf_spad_write(struct ntb_dev *ntb,
> +			      int idx, u32 val)
> +{
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +	u32 offset;
> +
> +	if (idx < 0 || idx >= ndev->spad_count) {
> +		dev_err(dev, "WRITE: Invalid ScratchPad Index %d\n", idx);
> +		return -EINVAL;
> +	}
> +
> +	offset = readl(ndev->ctrl_reg + NTB_EPF_SPAD_OFFSET);
> +	offset += (idx << 2);
> +	writel(val, ndev->ctrl_reg + offset);
> +
> +	return 0;
> +}
> +
> +static u32 ntb_epf_peer_spad_read(struct ntb_dev *ntb, int pidx, int
> +idx) {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +	u32 offset;
> +
> +	if (pidx != NTB_DEF_PEER_IDX) {
> +		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
> +		return -EINVAL;
> +	}
> +
> +	if (idx < 0 || idx >= ndev->spad_count) {
> +		dev_err(dev, "WRITE: Invalid Peer ScratchPad Index %d\n",
> idx);
> +		return -EINVAL;
> +	}
> +
> +	offset = (idx << 2);
> +	return readl(ndev->peer_spad_reg + offset); }
> +
> +static int ntb_epf_peer_spad_write(struct ntb_dev *ntb, int pidx,
> +				   int idx, u32 val)
> +{
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +	u32 offset;
> +
> +	if (pidx != NTB_DEF_PEER_IDX) {
> +		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
> +		return -EINVAL;
> +	}
> +
> +	if (idx < 0 || idx >= ndev->spad_count) {
> +		dev_err(dev, "WRITE: Invalid Peer ScratchPad Index %d\n",
> idx);
> +		return -EINVAL;
> +	}
> +
> +	offset = (idx << 2);
> +	writel(val, ndev->peer_spad_reg + offset);
> +
> +	return 0;
> +}
> +
> +static int ntb_epf_link_enable(struct ntb_dev *ntb,
> +			       enum ntb_speed max_speed,
> +			       enum ntb_width max_width)
> +{
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +	int ret;
> +
> +	ret = ntb_epf_send_command(ndev, CMD_LINK_UP, 0);
> +	if (ret) {
> +		dev_err(dev, "Fail to enable link\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ntb_epf_link_disable(struct ntb_dev *ntb) {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +	int ret;
> +
> +	ret = ntb_epf_send_command(ndev, CMD_LINK_DOWN, 0);
> +	if (ret) {
> +		dev_err(dev, "Fail to disable link\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static irqreturn_t ntb_epf_vec_isr(int irq, void *dev) {
> +	struct ntb_epf_dev *ndev = dev;
> +	int irq_no;
> +
> +	irq_no = irq - pci_irq_vector(ndev->ntb.pdev, 0);
> +	ndev->db_val = irq_no + 1;
> +
> +	if (irq_no == 0)
> +		ntb_link_event(&ndev->ntb);
> +	else
> +		ntb_db_event(&ndev->ntb, irq_no);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int ntb_epf_init_isr(struct ntb_epf_dev *ndev, int msi_min, int
> +msi_max) {
> +	struct pci_dev *pdev = ndev->ntb.pdev;
> +	struct device *dev = ndev->dev;
> +	u32 argument = MSIX_ENABLE;
> +	int irq;
> +	int ret;
> +	int i;
> +
> +	irq = pci_alloc_irq_vectors(pdev, msi_min, msi_max, PCI_IRQ_MSIX);
> +	if (irq < 0) {
> +		dev_dbg(dev, "Failed to get MSIX interrupts\n");
> +		irq = pci_alloc_irq_vectors(pdev, msi_min, msi_max,
> +					    PCI_IRQ_MSI);
> +		if (irq < 0) {
> +			dev_err(dev, "Failed to get MSI interrupts\n");
> +			return irq;
> +		}
> +		argument &= ~MSIX_ENABLE;
> +	}
> +
> +	for (i = 0; i < irq; i++) {
> +		ret = devm_request_irq(&pdev->dev, pci_irq_vector(pdev,
> i),
> +				       ntb_epf_vec_isr, 0, "ntb_epf", ndev);
> +		if (ret) {
> +			dev_err(dev, "Failed to request irq\n");
> +			goto err_request_irq;
> +		}
> +	}
> +
> +	ndev->db_count = irq - 1;
> +
> +	ret = ntb_epf_send_command(ndev, CMD_CONFIGURE_DOORBELL,
> +				   argument | irq);
> +	if (ret) {
> +		dev_err(dev, "Failed to configure doorbell\n");
> +		goto err_configure_db;
> +	}
> +
> +	return 0;
> +
> +err_configure_db:
> +	for (i = 0; i < ndev->db_count + 1; i++)
> +		devm_free_irq(dev, pci_irq_vector(pdev, i), ndev);
> +
> +err_request_irq:
> +	pci_free_irq_vectors(pdev);
> +
> +	return ret;
> +}
> +
> +static int ntb_epf_peer_mw_count(struct ntb_dev *ntb) {
> +	return ntb_ndev(ntb)->mw_count;
> +}
> +
> +static int ntb_epf_spad_count(struct ntb_dev *ntb) {
> +	return ntb_ndev(ntb)->spad_count;
> +}
> +
> +static u64 ntb_epf_db_valid_mask(struct ntb_dev *ntb) {
> +	return ntb_ndev(ntb)->db_valid_mask;
> +}
> +
> +static int ntb_epf_db_set_mask(struct ntb_dev *ntb, u64 db_bits) {
> +	return 0;
> +}
> +
> +static int ntb_epf_mw_set_trans(struct ntb_dev *ntb, int pidx, int idx,
> +				dma_addr_t addr, resource_size_t size) {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +	resource_size_t mw_size;
> +	int bar;
> +
> +	if (pidx != NTB_DEF_PEER_IDX) {
> +		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
> +		return -EINVAL;
> +	}
> +
> +	bar = idx + NTB_EPF_MW_OFFSET;
> +
> +	mw_size = pci_resource_len(ntb->pdev, bar);
> +
> +	if (size > mw_size) {
> +		dev_err(dev, "Size:%pa is greater than the MW size %pa\n",
> +			&size, &mw_size);
> +		return -EINVAL;
> +	}
> +
> +	writel(lower_32_bits(addr), ndev->ctrl_reg +
> NTB_EPF_LOWER_ADDR);
> +	writel(upper_32_bits(addr), ndev->ctrl_reg +
> NTB_EPF_UPPER_ADDR);
> +	writel(lower_32_bits(size), ndev->ctrl_reg + NTB_EPF_LOWER_SIZE);
> +	writel(upper_32_bits(size), ndev->ctrl_reg + NTB_EPF_UPPER_SIZE);
> +	ntb_epf_send_command(ndev, CMD_CONFIGURE_MW, idx);
> +
> +	return 0;
> +}
> +
> +static int ntb_epf_mw_clear_trans(struct ntb_dev *ntb, int pidx, int
> +idx) {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	struct device *dev = ndev->dev;
> +	int ret = 0;
> +
> +	ntb_epf_send_command(ndev, CMD_TEARDOWN_MW, idx);
> +	if (ret)
> +		dev_err(dev, "Failed to teardown memory window\n");
> +
> +	return ret;
> +}
> +
> +static int ntb_epf_peer_mw_get_addr(struct ntb_dev *ntb, int idx,
> +				    phys_addr_t *base, resource_size_t *size)
> {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	u32 offset = 0;
> +	int bar;
> +
> +	if (idx == 0)
> +		offset = readl(ndev->ctrl_reg + NTB_EPF_MW1_OFFSET);
> +
> +	bar = idx + NTB_EPF_MW_OFFSET;
> +
> +	if (base)
> +		*base = pci_resource_start(ndev->ntb.pdev, bar) + offset;
> +
> +	if (size)
> +		*size = pci_resource_len(ndev->ntb.pdev, bar) - offset;
> +
> +	return 0;
> +}
> +
> +static int ntb_epf_peer_db_set(struct ntb_dev *ntb, u64 db_bits) {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +	u32 interrupt_num = ffs(db_bits) + 1;
> +	struct device *dev = ndev->dev;
> +	u32 db_entry_size;
> +	u32 db_offset;
> +	u32 db_data;
> +
> +	if (interrupt_num > ndev->db_count) {
> +		dev_err(dev, "DB interrupt %d greater than Max Supported
> %d\n",
> +			interrupt_num, ndev->db_count);
> +		return -EINVAL;
> +	}
> +
> +	db_entry_size = readl(ndev->ctrl_reg + NTB_EPF_DB_ENTRY_SIZE);
> +
> +	db_data = readl(ndev->ctrl_reg +
> NTB_EPF_DB_DATA(interrupt_num));
> +	db_offset = readl(ndev->ctrl_reg +
> NTB_EPF_DB_OFFSET(interrupt_num));
> +	writel(db_data, ndev->db_reg + (db_entry_size * interrupt_num) +
> +	       db_offset);
> +
> +	return 0;
> +}
> +
> +static u64 ntb_epf_db_read(struct ntb_dev *ntb) {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +
> +	return ndev->db_val;
> +}
> +
> +static int ntb_epf_db_clear_mask(struct ntb_dev *ntb, u64 db_bits) {
> +	return 0;
> +}
> +
> +static int ntb_epf_db_clear(struct ntb_dev *ntb, u64 db_bits) {
> +	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
> +
> +	ndev->db_val = 0;
> +
> +	return 0;
> +}
> +
> +static const struct ntb_dev_ops ntb_epf_ops = {
> +	.mw_count		= ntb_epf_mw_count,
> +	.spad_count		= ntb_epf_spad_count,
> +	.peer_mw_count		= ntb_epf_peer_mw_count,
> +	.db_valid_mask		= ntb_epf_db_valid_mask,
> +	.db_set_mask		= ntb_epf_db_set_mask,
> +	.mw_set_trans		= ntb_epf_mw_set_trans,
> +	.mw_clear_trans		= ntb_epf_mw_clear_trans,
> +	.peer_mw_get_addr	= ntb_epf_peer_mw_get_addr,
> +	.link_enable		= ntb_epf_link_enable,
> +	.spad_read		= ntb_epf_spad_read,
> +	.spad_write		= ntb_epf_spad_write,
> +	.peer_spad_read		= ntb_epf_peer_spad_read,
> +	.peer_spad_write	= ntb_epf_peer_spad_write,
> +	.peer_db_set		= ntb_epf_peer_db_set,
> +	.db_read		= ntb_epf_db_read,
> +	.mw_get_align		= ntb_epf_mw_get_align,
> +	.link_is_up		= ntb_epf_link_is_up,
> +	.db_clear_mask		= ntb_epf_db_clear_mask,
> +	.db_clear		= ntb_epf_db_clear,
> +	.link_disable		= ntb_epf_link_disable,
> +};
> +
> +static inline void ntb_epf_init_struct(struct ntb_epf_dev *ndev,
> +				       struct pci_dev *pdev)
> +{
> +	ndev->ntb.pdev = pdev;
> +	ndev->ntb.topo = NTB_TOPO_NONE;
> +	ndev->ntb.ops = &ntb_epf_ops;
> +}
> +
> +static int ntb_epf_init_dev(struct ntb_epf_dev *ndev) {
> +	struct device *dev = ndev->dev;
> +	int ret;
> +
> +	/* One Link interrupt and rest doorbell interrupt */
> +	ret = ntb_epf_init_isr(ndev, NTB_EPF_MIN_DB_COUNT + 1,
> +			       NTB_EPF_MAX_DB_COUNT + 1);
> +	if (ret) {
> +		dev_err(dev, "Failed to init ISR\n");
> +		return ret;
> +	}
> +
> +	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);
> +
> +	return 0;
> +}
> +
> +static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
> +			    struct pci_dev *pdev)
> +{
> +	struct device *dev = ndev->dev;
> +	int ret;
> +
> +	pci_set_drvdata(pdev, ndev);
> +
> +	ret = pci_enable_device(pdev);
> +	if (ret) {
> +		dev_err(dev, "Cannot enable PCI device\n");
> +		goto err_pci_enable;
> +	}
> +
> +	ret = pci_request_regions(pdev, "ntb");
> +	if (ret) {
> +		dev_err(dev, "Cannot obtain PCI resources\n");
> +		goto err_pci_regions;
> +	}
> +
> +	pci_set_master(pdev);
> +
> +	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
> +	if (ret) {
> +		ret = dma_set_mask_and_coherent(dev,
> DMA_BIT_MASK(32));
> +		if (ret) {
> +			dev_err(dev, "Cannot set DMA mask\n");
> +			goto err_dma_mask;
> +		}
> +		dev_warn(&pdev->dev, "Cannot DMA highmem\n");
> +	}
> +
> +	ndev->ctrl_reg = pci_iomap(pdev, ndev->ctrl_reg_bar, 0);
> +	if (!ndev->ctrl_reg) {
> +		ret = -EIO;
> +		goto err_dma_mask;
> +	}
> +
> +	ndev->peer_spad_reg = pci_iomap(pdev, ndev-
> >peer_spad_reg_bar, 0);
> +	if (!ndev->peer_spad_reg) {
> +		ret = -EIO;
> +		goto err_dma_mask;
> +	}
> +
> +	ndev->db_reg = pci_iomap(pdev, ndev->db_reg_bar, 0);
> +	if (!ndev->db_reg) {
> +		ret = -EIO;
> +		goto err_dma_mask;
> +	}
> +
> +	return 0;
> +
> +err_dma_mask:
> +	pci_clear_master(pdev);
> +
> +err_pci_regions:
> +	pci_disable_device(pdev);
> +
> +err_pci_enable:
> +	pci_set_drvdata(pdev, NULL);
> +
> +	return ret;
> +}
> +
> +static void ntb_epf_deinit_pci(struct ntb_epf_dev *ndev) {
> +	struct pci_dev *pdev = ndev->ntb.pdev;
> +
> +	pci_iounmap(pdev, ndev->ctrl_reg);
> +	pci_iounmap(pdev, ndev->peer_spad_reg);
> +	pci_iounmap(pdev, ndev->db_reg);
> +
> +	pci_clear_master(pdev);
> +	pci_release_regions(pdev);
> +	pci_disable_device(pdev);
> +	pci_set_drvdata(pdev, NULL);
> +}
> +
> +static void ntb_epf_cleanup_isr(struct ntb_epf_dev *ndev) {
> +	struct pci_dev *pdev = ndev->ntb.pdev;
> +	struct device *dev = &pdev->dev;
> +	int i;
> +
> +	ntb_epf_send_command(ndev, CMD_TEARDOWN_DOORBELL,
> ndev->db_count + 1);
> +
> +	for (i = 0; i < ndev->db_count + 1; i++)
> +		devm_free_irq(dev, pci_irq_vector(pdev, i), ndev);

This is called during shutdown. Does that defeats the purpose of using devm API?

- Dave

> +	pci_free_irq_vectors(pdev);
> +}
> +
> +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;
> +	struct device *dev = &pdev->dev;
> +	struct ntb_epf_data *data;
> +	struct ntb_epf_dev *ndev;
> +	int ret;
> +
> +	if (pci_is_bridge(pdev))
> +		return -ENODEV;
> +
> +	ndev = devm_kzalloc(dev, sizeof(*ndev), GFP_KERNEL);
> +	if (!ndev)
> +		return -ENOMEM;
> +
> +	data = (struct ntb_epf_data *)id->driver_data;
> +	if (data) {
> +		if (data->peer_spad_reg_bar)
> +			peer_spad_reg_bar = data->peer_spad_reg_bar;
> +		if (data->ctrl_reg_bar)
> +			ctrl_reg_bar = data->ctrl_reg_bar;
> +		if (data->db_reg_bar)
> +			db_reg_bar = data->db_reg_bar;
> +	}
> +
> +	ndev->peer_spad_reg_bar = peer_spad_reg_bar;
> +	ndev->ctrl_reg_bar = ctrl_reg_bar;
> +	ndev->db_reg_bar = db_reg_bar;
> +	ndev->dev = dev;
> +
> +	ntb_epf_init_struct(ndev, pdev);
> +	mutex_init(&ndev->cmd_lock);
> +
> +	ret = ntb_epf_init_pci(ndev, pdev);
> +	if (ret) {
> +		dev_err(dev, "Failed to init PCI\n");
> +		return ret;
> +	}
> +
> +	ret = ntb_epf_init_dev(ndev);
> +	if (ret) {
> +		dev_err(dev, "Failed to init device\n");
> +		goto err_init_dev;
> +	}
> +
> +	ret = ntb_register_device(&ndev->ntb);
> +	if (ret) {
> +		dev_err(dev, "Failed to register NTB device\n");
> +		goto err_register_dev;
> +	}
> +
> +	return 0;
> +
> +err_register_dev:
> +	ntb_epf_cleanup_isr(ndev);
> +
> +err_init_dev:
> +	ntb_epf_deinit_pci(ndev);
> +
> +	return ret;
> +}
> +
> +static void ntb_epf_pci_remove(struct pci_dev *pdev) {
> +	struct ntb_epf_dev *ndev = pci_get_drvdata(pdev);
> +
> +	ntb_unregister_device(&ndev->ntb);
> +	ntb_epf_cleanup_isr(ndev);
> +	ntb_epf_deinit_pci(ndev);
> +	kfree(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,
> +};
> +
> +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,
> +	},
> +	{ },
> +};
> +
> +static struct pci_driver ntb_epf_pci_driver = {
> +	.name		= KBUILD_MODNAME,
> +	.id_table	= ntb_epf_pci_tbl,
> +	.probe		= ntb_epf_pci_probe,
> +	.remove		= ntb_epf_pci_remove,
> +};
> +module_pci_driver(ntb_epf_pci_driver);
> +
> +MODULE_DESCRIPTION("PCI ENDPOINT NTB HOST DRIVER");
> +MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.17.1