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(addr: chip->regs + HSU_PCI_DMAISR);
37 for_each_set_bit(i, &dmaisr, chip->hsu->nr_channels) {
38 err = hsu_dma_get_status(chip, nr: i, status: &status);
39 if (err > 0)
40 ret |= 1;
41 else if (err == 0)
42 ret |= hsu_dma_do_irq(chip, nr: 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), name: 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(dev: pdev);
70 pci_try_set_mwi(dev: pdev);
71
72 ret = dma_set_mask_and_coherent(dev: &pdev->dev, DMA_BIT_MASK(32));
73 if (ret)
74 return ret;
75
76 chip = devm_kzalloc(dev: &pdev->dev, size: sizeof(*chip), GFP_KERNEL);
77 if (!chip)
78 return -ENOMEM;
79
80 ret = pci_alloc_irq_vectors(dev: pdev, min_vecs: 1, max_vecs: 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(dev: pdev, nr: 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, irq: chip->irq, handler: hsu_pci_irq, irqflags: 0, devname: "hsu_dma_pci", dev_id: 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(irq: chip->irq);
112
113 pci_set_drvdata(pdev, data: 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

source code of linux/drivers/dma/hsu/pci.c