drivers/dma/hsu/pci.c

   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
  27 static 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
  48 static void hsu_pci_dma_remove(void *chip)
  49 {
  50         hsu_dma_remove(chip);
  51 }
  52
  53 static 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
 118 static 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 };
 123 MODULE_DEVICE_TABLE(pci, hsu_pci_id_table);
 124
 125 static 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
 131 module_pci_driver(hsu_pci_driver);
 132
 133 MODULE_LICENSE("GPL v2");
 134 MODULE_DESCRIPTION("High Speed UART DMA PCI driver");
 135 MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");