1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PCI driver for the High Speed UART DMA
4 *
5 * Copyright (C) 2015 Intel Corporation
6 * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
7 *
8 * Partially based on the bits found in drivers/tty/serial/mfd.c.
9 */
10
11#include <linux/bitops.h>
12#include <linux/device.h>
13#include <linux/interrupt.h>
14#include <linux/module.h>
15#include <linux/pci.h>
16
17#include "hsu.h"
18
19#define HSU_PCI_DMASR		0x00
20#define HSU_PCI_DMAISR		0x04
21
22#define HSU_PCI_CHAN_OFFSET	0x100
23
24#define PCI_DEVICE_ID_INTEL_MFLD_HSU_DMA	0x081e
25#define PCI_DEVICE_ID_INTEL_MRFLD_HSU_DMA	0x1192
26
27static irqreturn_t hsu_pci_irq(int irq, void *dev)
28{
29	struct hsu_dma_chip *chip = dev;
30	unsigned long dmaisr;
31	unsigned short i;
32	u32 status;
33	int ret = 0;
34	int err;
35
36	dmaisr = readl(chip->regs + HSU_PCI_DMAISR);
37	for_each_set_bit(i, &dmaisr, chip->hsu->nr_channels) {
38		err = hsu_dma_get_status(chip, i, &status);
39		if (err > 0)
40			ret |= 1;
41		else if (err == 0)
42			ret |= hsu_dma_do_irq(chip, i, status);
43	}
44
45	return IRQ_RETVAL(ret);
46}
47
48static void hsu_pci_dma_remove(void *chip)
49{
50	hsu_dma_remove(chip);
51}
52
53static int hsu_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
54{
55	struct device *dev = &pdev->dev;
56	struct hsu_dma_chip *chip;
57	int ret;
58
59	ret = pcim_enable_device(pdev);
60	if (ret)
61		return ret;
62
63	ret = pcim_iomap_regions(pdev, BIT(0), pci_name(pdev));
64	if (ret) {
65		dev_err(&pdev->dev, "I/O memory remapping failed\n");
66		return ret;
67	}
68
69	pci_set_master(pdev);
70	pci_try_set_mwi(pdev);
71
72	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
73	if (ret)
74		return ret;
75
76	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
77	if (!chip)
78		return -ENOMEM;
79
80	ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
81	if (ret < 0)
82		return ret;
83
84	chip->dev = &pdev->dev;
85	chip->regs = pcim_iomap_table(pdev)[0];
86	chip->length = pci_resource_len(pdev, 0);
87	chip->offset = HSU_PCI_CHAN_OFFSET;
88	chip->irq = pci_irq_vector(pdev, 0);
89
90	ret = hsu_dma_probe(chip);
91	if (ret)
92		return ret;
93
94	ret = devm_add_action_or_reset(dev, hsu_pci_dma_remove, chip);
95	if (ret)
96		return ret;
97
98	ret = devm_request_irq(dev, chip->irq, hsu_pci_irq, 0, "hsu_dma_pci", chip);
99	if (ret)
100		return ret;
101
102	/*
103	 * On Intel Tangier B0 and Anniedale the interrupt line, disregarding
104	 * to have different numbers, is shared between HSU DMA and UART IPs.
105	 * Thus on such SoCs we are expecting that IRQ handler is called in
106	 * UART driver only. Instead of handling the spurious interrupt
107	 * from HSU DMA here and waste CPU time and delay HSU UART interrupt
108	 * handling, disable the interrupt entirely.
109	 */
110	if (pdev->device == PCI_DEVICE_ID_INTEL_MRFLD_HSU_DMA)
111		disable_irq_nosync(chip->irq);
112
113	pci_set_drvdata(pdev, chip);
114
115	return 0;
116}
117
118static const struct pci_device_id hsu_pci_id_table[] = {
119	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_MFLD_HSU_DMA), 0 },
120	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_MRFLD_HSU_DMA), 0 },
121	{ }
122};
123MODULE_DEVICE_TABLE(pci, hsu_pci_id_table);
124
125static struct pci_driver hsu_pci_driver = {
126	.name		= "hsu_dma_pci",
127	.id_table	= hsu_pci_id_table,
128	.probe		= hsu_pci_probe,
129};
130
131module_pci_driver(hsu_pci_driver);
132
133MODULE_LICENSE("GPL v2");
134MODULE_DESCRIPTION("High Speed UART DMA PCI driver");
135MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
136