drivers/dma/hsu/pci.c

   1 /*
   2  * PCI driver for the High Speed UART DMA
   3  *
   4  * Copyright (C) 2015 Intel Corporation
   5  * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
   6  *
   7  * Partially based on the bits found in drivers/tty/serial/mfd.c.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/bitops.h>
  15 #include <linux/device.h>
  16 #include <linux/module.h>
  17 #include <linux/pci.h>
  18
  19 #include "hsu.h"
  20
  21 #define HSU_PCI_DMASR           0x00
  22 #define HSU_PCI_DMAISR          0x04
  23
  24 #define HSU_PCI_CHAN_OFFSET     0x100
  25
  26 #define PCI_DEVICE_ID_INTEL_MFLD_HSU_DMA        0x081e
  27 #define PCI_DEVICE_ID_INTEL_MRFLD_HSU_DMA       0x1192
  28
  29 static irqreturn_t hsu_pci_irq(int irq, void *dev)
  30 {
  31         struct hsu_dma_chip *chip = dev;
  32         struct pci_dev *pdev = to_pci_dev(chip->dev);
  33         u32 dmaisr;
  34         u32 status;
  35         unsigned short i;
  36         int ret = 0;
  37         int err;
  38
  39         /*
  40          * On Intel Tangier B0 and Anniedale the interrupt line, disregarding
  41          * to have different numbers, is shared between HSU DMA and UART IPs.
  42          * Thus on such SoCs we are expecting that IRQ handler is called in
  43          * UART driver only.
  44          */
  45         if (pdev->device == PCI_DEVICE_ID_INTEL_MRFLD_HSU_DMA)
  46                 return IRQ_HANDLED;
  47
  48         dmaisr = readl(chip->regs + HSU_PCI_DMAISR);
  49         for (i = 0; i < chip->hsu->nr_channels; i++) {
  50                 if (dmaisr & 0x1) {
  51                         err = hsu_dma_get_status(chip, i, &status);
  52                         if (err > 0)
  53                                 ret |= 1;
  54                         else if (err == 0)
  55                                 ret |= hsu_dma_do_irq(chip, i, status);
  56                 }
  57                 dmaisr >>= 1;
  58         }
  59
  60         return IRQ_RETVAL(ret);
  61 }
  62
  63 static int hsu_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
  64 {
  65         struct hsu_dma_chip *chip;
  66         int ret;
  67
  68         ret = pcim_enable_device(pdev);
  69         if (ret)
  70                 return ret;
  71
  72         ret = pcim_iomap_regions(pdev, BIT(0), pci_name(pdev));
  73         if (ret) {
  74                 dev_err(&pdev->dev, "I/O memory remapping failed\n");
  75                 return ret;
  76         }
  77
  78         pci_set_master(pdev);
  79         pci_try_set_mwi(pdev);
  80
  81         ret = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
  82         if (ret)
  83                 return ret;
  84
  85         ret = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
  86         if (ret)
  87                 return ret;
  88
  89         chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
  90         if (!chip)
  91                 return -ENOMEM;
  92
  93         ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
  94         if (ret < 0)
  95                 return ret;
  96
  97         chip->dev = &pdev->dev;
  98         chip->regs = pcim_iomap_table(pdev)[0];
  99         chip->length = pci_resource_len(pdev, 0);
 100         chip->offset = HSU_PCI_CHAN_OFFSET;
 101         chip->irq = pci_irq_vector(pdev, 0);
 102
 103         ret = hsu_dma_probe(chip);
 104         if (ret)
 105                 return ret;
 106
 107         ret = request_irq(chip->irq, hsu_pci_irq, 0, "hsu_dma_pci", chip);
 108         if (ret)
 109                 goto err_register_irq;
 110
 111         pci_set_drvdata(pdev, chip);
 112
 113         return 0;
 114
 115 err_register_irq:
 116         hsu_dma_remove(chip);
 117         return ret;
 118 }
 119
 120 static void hsu_pci_remove(struct pci_dev *pdev)
 121 {
 122         struct hsu_dma_chip *chip = pci_get_drvdata(pdev);
 123
 124         free_irq(chip->irq, chip);
 125         hsu_dma_remove(chip);
 126 }
 127
 128 static const struct pci_device_id hsu_pci_id_table[] = {
 129         { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_MFLD_HSU_DMA), 0 },
 130         { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_MRFLD_HSU_DMA), 0 },
 131         { }
 132 };
 133 MODULE_DEVICE_TABLE(pci, hsu_pci_id_table);
 134
 135 static struct pci_driver hsu_pci_driver = {
 136         .name           = "hsu_dma_pci",
 137         .id_table       = hsu_pci_id_table,
 138         .probe          = hsu_pci_probe,
 139         .remove         = hsu_pci_remove,
 140 };
 141
 142 module_pci_driver(hsu_pci_driver);
 143
 144 MODULE_LICENSE("GPL v2");
 145 MODULE_DESCRIPTION("High Speed UART DMA PCI driver");
 146 MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");