cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ems_pcmcia.c (7884B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright (C) 2008 Sebastian Haas (initial chardev implementation)
      4 * Copyright (C) 2010 Markus Plessing <plessing@ems-wuensche.com>
      5 * Rework for mainline by Oliver Hartkopp <socketcan@hartkopp.net>
      6 */
      7
      8#include <linux/kernel.h>
      9#include <linux/module.h>
     10#include <linux/interrupt.h>
     11#include <linux/netdevice.h>
     12#include <linux/delay.h>
     13#include <linux/io.h>
     14#include <pcmcia/cistpl.h>
     15#include <pcmcia/ds.h>
     16#include <linux/can.h>
     17#include <linux/can/dev.h>
     18#include "sja1000.h"
     19
     20#define DRV_NAME "ems_pcmcia"
     21
     22MODULE_AUTHOR("Markus Plessing <plessing@ems-wuensche.com>");
     23MODULE_DESCRIPTION("Socket-CAN driver for EMS CPC-CARD cards");
     24MODULE_LICENSE("GPL v2");
     25
     26#define EMS_PCMCIA_MAX_CHAN 2
     27
     28struct ems_pcmcia_card {
     29	int channels;
     30	struct pcmcia_device *pcmcia_dev;
     31	struct net_device *net_dev[EMS_PCMCIA_MAX_CHAN];
     32	void __iomem *base_addr;
     33};
     34
     35#define EMS_PCMCIA_CAN_CLOCK (16000000 / 2)
     36
     37/*
     38 * The board configuration is probably following:
     39 * RX1 is connected to ground.
     40 * TX1 is not connected.
     41 * CLKO is not connected.
     42 * Setting the OCR register to 0xDA is a good idea.
     43 * This means  normal output mode , push-pull and the correct polarity.
     44 */
     45#define EMS_PCMCIA_OCR (OCR_TX0_PUSHPULL | OCR_TX1_PUSHPULL)
     46
     47/*
     48 * In the CDR register, you should set CBP to 1.
     49 * You will probably also want to set the clock divider value to 7
     50 * (meaning direct oscillator output) because the second SJA1000 chip
     51 * is driven by the first one CLKOUT output.
     52 */
     53#define EMS_PCMCIA_CDR (CDR_CBP | CDR_CLKOUT_MASK)
     54#define EMS_PCMCIA_MEM_SIZE 4096 /* Size of the remapped io-memory */
     55#define EMS_PCMCIA_CAN_BASE_OFFSET 0x100 /* Offset where controllers starts */
     56#define EMS_PCMCIA_CAN_CTRL_SIZE 0x80 /* Memory size for each controller */
     57
     58#define EMS_CMD_RESET 0x00 /* Perform a reset of the card */
     59#define EMS_CMD_MAP   0x03 /* Map CAN controllers into card' memory */
     60#define EMS_CMD_UMAP  0x02 /* Unmap CAN controllers from card' memory */
     61
     62static struct pcmcia_device_id ems_pcmcia_tbl[] = {
     63	PCMCIA_DEVICE_PROD_ID123("EMS_T_W", "CPC-Card", "V2.0", 0xeab1ea23,
     64				 0xa338573f, 0xe4575800),
     65	PCMCIA_DEVICE_NULL,
     66};
     67
     68MODULE_DEVICE_TABLE(pcmcia, ems_pcmcia_tbl);
     69
     70static u8 ems_pcmcia_read_reg(const struct sja1000_priv *priv, int port)
     71{
     72	return readb(priv->reg_base + port);
     73}
     74
     75static void ems_pcmcia_write_reg(const struct sja1000_priv *priv, int port,
     76				 u8 val)
     77{
     78	writeb(val, priv->reg_base + port);
     79}
     80
     81static irqreturn_t ems_pcmcia_interrupt(int irq, void *dev_id)
     82{
     83	struct ems_pcmcia_card *card = dev_id;
     84	struct net_device *dev;
     85	irqreturn_t retval = IRQ_NONE;
     86	int i, again;
     87
     88	/* Card not present */
     89	if (readw(card->base_addr) != 0xAA55)
     90		return IRQ_HANDLED;
     91
     92	do {
     93		again = 0;
     94
     95		/* Check interrupt for each channel */
     96		for (i = 0; i < card->channels; i++) {
     97			dev = card->net_dev[i];
     98			if (!dev)
     99				continue;
    100
    101			if (sja1000_interrupt(irq, dev) == IRQ_HANDLED)
    102				again = 1;
    103		}
    104		/* At least one channel handled the interrupt */
    105		if (again)
    106			retval = IRQ_HANDLED;
    107
    108	} while (again);
    109
    110	return retval;
    111}
    112
    113/*
    114 * Check if a CAN controller is present at the specified location
    115 * by trying to set 'em into the PeliCAN mode
    116 */
    117static inline int ems_pcmcia_check_chan(struct sja1000_priv *priv)
    118{
    119	/* Make sure SJA1000 is in reset mode */
    120	ems_pcmcia_write_reg(priv, SJA1000_MOD, 1);
    121	ems_pcmcia_write_reg(priv, SJA1000_CDR, CDR_PELICAN);
    122
    123	/* read reset-values */
    124	if (ems_pcmcia_read_reg(priv, SJA1000_CDR) == CDR_PELICAN)
    125		return 1;
    126
    127	return 0;
    128}
    129
    130static void ems_pcmcia_del_card(struct pcmcia_device *pdev)
    131{
    132	struct ems_pcmcia_card *card = pdev->priv;
    133	struct net_device *dev;
    134	int i;
    135
    136	free_irq(pdev->irq, card);
    137
    138	for (i = 0; i < card->channels; i++) {
    139		dev = card->net_dev[i];
    140		if (!dev)
    141			continue;
    142
    143		printk(KERN_INFO "%s: removing %s on channel #%d\n",
    144		       DRV_NAME, dev->name, i);
    145		unregister_sja1000dev(dev);
    146		free_sja1000dev(dev);
    147	}
    148
    149	writeb(EMS_CMD_UMAP, card->base_addr);
    150	iounmap(card->base_addr);
    151	kfree(card);
    152
    153	pdev->priv = NULL;
    154}
    155
    156/*
    157 * Probe PCI device for EMS CAN signature and register each available
    158 * CAN channel to SJA1000 Socket-CAN subsystem.
    159 */
    160static int ems_pcmcia_add_card(struct pcmcia_device *pdev, unsigned long base)
    161{
    162	struct sja1000_priv *priv;
    163	struct net_device *dev;
    164	struct ems_pcmcia_card *card;
    165	int err, i;
    166
    167	/* Allocating card structures to hold addresses, ... */
    168	card = kzalloc(sizeof(struct ems_pcmcia_card), GFP_KERNEL);
    169	if (!card)
    170		return -ENOMEM;
    171
    172	pdev->priv = card;
    173	card->channels = 0;
    174
    175	card->base_addr = ioremap(base, EMS_PCMCIA_MEM_SIZE);
    176	if (!card->base_addr) {
    177		err = -ENOMEM;
    178		goto failure_cleanup;
    179	}
    180
    181	/* Check for unique EMS CAN signature */
    182	if (readw(card->base_addr) != 0xAA55) {
    183		err = -ENODEV;
    184		goto failure_cleanup;
    185	}
    186
    187	/* Request board reset */
    188	writeb(EMS_CMD_RESET, card->base_addr);
    189
    190	/* Make sure CAN controllers are mapped into card's memory space */
    191	writeb(EMS_CMD_MAP, card->base_addr);
    192
    193	/* Detect available channels */
    194	for (i = 0; i < EMS_PCMCIA_MAX_CHAN; i++) {
    195		dev = alloc_sja1000dev(0);
    196		if (!dev) {
    197			err = -ENOMEM;
    198			goto failure_cleanup;
    199		}
    200
    201		card->net_dev[i] = dev;
    202		priv = netdev_priv(dev);
    203		priv->priv = card;
    204		SET_NETDEV_DEV(dev, &pdev->dev);
    205		dev->dev_id = i;
    206
    207		priv->irq_flags = IRQF_SHARED;
    208		dev->irq = pdev->irq;
    209		priv->reg_base = card->base_addr + EMS_PCMCIA_CAN_BASE_OFFSET +
    210			(i * EMS_PCMCIA_CAN_CTRL_SIZE);
    211
    212		/* Check if channel is present */
    213		if (ems_pcmcia_check_chan(priv)) {
    214			priv->read_reg  = ems_pcmcia_read_reg;
    215			priv->write_reg = ems_pcmcia_write_reg;
    216			priv->can.clock.freq = EMS_PCMCIA_CAN_CLOCK;
    217			priv->ocr = EMS_PCMCIA_OCR;
    218			priv->cdr = EMS_PCMCIA_CDR;
    219			priv->flags |= SJA1000_CUSTOM_IRQ_HANDLER;
    220
    221			/* Register SJA1000 device */
    222			err = register_sja1000dev(dev);
    223			if (err) {
    224				free_sja1000dev(dev);
    225				goto failure_cleanup;
    226			}
    227
    228			card->channels++;
    229
    230			printk(KERN_INFO "%s: registered %s on channel "
    231			       "#%d at 0x%p, irq %d\n", DRV_NAME, dev->name,
    232			       i, priv->reg_base, dev->irq);
    233		} else
    234			free_sja1000dev(dev);
    235	}
    236
    237	if (!card->channels) {
    238		err = -ENODEV;
    239		goto failure_cleanup;
    240	}
    241
    242	err = request_irq(pdev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
    243			  DRV_NAME, card);
    244	if (!err)
    245		return 0;
    246
    247failure_cleanup:
    248	ems_pcmcia_del_card(pdev);
    249	return err;
    250}
    251
    252/*
    253 * Setup PCMCIA socket and probe for EMS CPC-CARD
    254 */
    255static int ems_pcmcia_probe(struct pcmcia_device *dev)
    256{
    257	int csval;
    258
    259	/* General socket configuration */
    260	dev->config_flags |= CONF_ENABLE_IRQ;
    261	dev->config_index = 1;
    262	dev->config_regs = PRESENT_OPTION;
    263
    264	/* The io structure describes IO port mapping */
    265	dev->resource[0]->end = 16;
    266	dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;
    267	dev->resource[1]->end = 16;
    268	dev->resource[1]->flags |= IO_DATA_PATH_WIDTH_16;
    269	dev->io_lines = 5;
    270
    271	/* Allocate a memory window */
    272	dev->resource[2]->flags =
    273		(WIN_DATA_WIDTH_8 | WIN_MEMORY_TYPE_CM | WIN_ENABLE);
    274	dev->resource[2]->start = dev->resource[2]->end = 0;
    275
    276	csval = pcmcia_request_window(dev, dev->resource[2], 0);
    277	if (csval) {
    278		dev_err(&dev->dev, "pcmcia_request_window failed (err=%d)\n",
    279			csval);
    280		return 0;
    281	}
    282
    283	csval = pcmcia_map_mem_page(dev, dev->resource[2], dev->config_base);
    284	if (csval) {
    285		dev_err(&dev->dev, "pcmcia_map_mem_page failed (err=%d)\n",
    286			csval);
    287		return 0;
    288	}
    289
    290	csval = pcmcia_enable_device(dev);
    291	if (csval) {
    292		dev_err(&dev->dev, "pcmcia_enable_device failed (err=%d)\n",
    293			csval);
    294		return 0;
    295	}
    296
    297	ems_pcmcia_add_card(dev, dev->resource[2]->start);
    298	return 0;
    299}
    300
    301/*
    302 * Release claimed resources
    303 */
    304static void ems_pcmcia_remove(struct pcmcia_device *dev)
    305{
    306	ems_pcmcia_del_card(dev);
    307	pcmcia_disable_device(dev);
    308}
    309
    310static struct pcmcia_driver ems_pcmcia_driver = {
    311	.name = DRV_NAME,
    312	.probe = ems_pcmcia_probe,
    313	.remove = ems_pcmcia_remove,
    314	.id_table = ems_pcmcia_tbl,
    315};
    316module_pcmcia_driver(ems_pcmcia_driver);