linux/drivers/net/ibm_newemac/mal.c
David Gibson 1d3bb99648 Device tree aware EMAC driver
Based on BenH's earlier work, this is a new version of the EMAC driver
for the built-in ethernet found on PowerPC 4xx embedded CPUs.  The
same ASIC is also found in the Axon bridge chip.  This new version is
designed to work in the arch/powerpc tree, using the device tree to
probe the device, rather than the old and ugly arch/ppc OCP layer.

This driver is designed to sit alongside the old driver (that lies in
drivers/net/ibm_emac and this one in drivers/net/ibm_newemac).  The
old driver is left in place to support arch/ppc until arch/ppc itself
reaches its final demise (not too long now, with luck).

This driver still has a number of things that could do with cleaning
up, but I think they can be fixed up after merging.  Specifically:
	- Should be adjusted to properly use the dma mapping API.
Axon needs this.
	- Probe logic needs reworking, in conjuction with the general
probing code for of_platform devices.  The dependencies here between
EMAC, MAL, ZMII etc. make this complicated.  At present, it usually
works, because we initialize and register the sub-drivers before the
EMAC driver itself, and (being in driver code) runs after the devices
themselves have been instantiated from the device tree.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-10-10 16:51:52 -07:00

729 lines
18 KiB
C

/*
* drivers/net/ibm_newemac/mal.c
*
* Memory Access Layer (MAL) support
*
* Copyright (c) 2004, 2005 Zultys Technologies.
* Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
*
* Based on original work by
* Benjamin Herrenschmidt <benh@kernel.crashing.org>,
* David Gibson <hermes@gibson.dropbear.id.au>,
*
* Armin Kuster <akuster@mvista.com>
* Copyright 2002 MontaVista Softare Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
*/
#include <linux/delay.h>
#include "core.h"
static int mal_count;
int __devinit mal_register_commac(struct mal_instance *mal,
struct mal_commac *commac)
{
unsigned long flags;
spin_lock_irqsave(&mal->lock, flags);
MAL_DBG(mal, "reg(%08x, %08x)" NL,
commac->tx_chan_mask, commac->rx_chan_mask);
/* Don't let multiple commacs claim the same channel(s) */
if ((mal->tx_chan_mask & commac->tx_chan_mask) ||
(mal->rx_chan_mask & commac->rx_chan_mask)) {
spin_unlock_irqrestore(&mal->lock, flags);
printk(KERN_WARNING "mal%d: COMMAC channels conflict!\n",
mal->index);
return -EBUSY;
}
mal->tx_chan_mask |= commac->tx_chan_mask;
mal->rx_chan_mask |= commac->rx_chan_mask;
list_add(&commac->list, &mal->list);
spin_unlock_irqrestore(&mal->lock, flags);
return 0;
}
void __devexit mal_unregister_commac(struct mal_instance *mal,
struct mal_commac *commac)
{
unsigned long flags;
spin_lock_irqsave(&mal->lock, flags);
MAL_DBG(mal, "unreg(%08x, %08x)" NL,
commac->tx_chan_mask, commac->rx_chan_mask);
mal->tx_chan_mask &= ~commac->tx_chan_mask;
mal->rx_chan_mask &= ~commac->rx_chan_mask;
list_del_init(&commac->list);
spin_unlock_irqrestore(&mal->lock, flags);
}
int mal_set_rcbs(struct mal_instance *mal, int channel, unsigned long size)
{
BUG_ON(channel < 0 || channel >= mal->num_rx_chans ||
size > MAL_MAX_RX_SIZE);
MAL_DBG(mal, "set_rbcs(%d, %lu)" NL, channel, size);
if (size & 0xf) {
printk(KERN_WARNING
"mal%d: incorrect RX size %lu for the channel %d\n",
mal->index, size, channel);
return -EINVAL;
}
set_mal_dcrn(mal, MAL_RCBS(channel), size >> 4);
return 0;
}
int mal_tx_bd_offset(struct mal_instance *mal, int channel)
{
BUG_ON(channel < 0 || channel >= mal->num_tx_chans);
return channel * NUM_TX_BUFF;
}
int mal_rx_bd_offset(struct mal_instance *mal, int channel)
{
BUG_ON(channel < 0 || channel >= mal->num_rx_chans);
return mal->num_tx_chans * NUM_TX_BUFF + channel * NUM_RX_BUFF;
}
void mal_enable_tx_channel(struct mal_instance *mal, int channel)
{
unsigned long flags;
spin_lock_irqsave(&mal->lock, flags);
MAL_DBG(mal, "enable_tx(%d)" NL, channel);
set_mal_dcrn(mal, MAL_TXCASR,
get_mal_dcrn(mal, MAL_TXCASR) | MAL_CHAN_MASK(channel));
spin_unlock_irqrestore(&mal->lock, flags);
}
void mal_disable_tx_channel(struct mal_instance *mal, int channel)
{
set_mal_dcrn(mal, MAL_TXCARR, MAL_CHAN_MASK(channel));
MAL_DBG(mal, "disable_tx(%d)" NL, channel);
}
void mal_enable_rx_channel(struct mal_instance *mal, int channel)
{
unsigned long flags;
spin_lock_irqsave(&mal->lock, flags);
MAL_DBG(mal, "enable_rx(%d)" NL, channel);
set_mal_dcrn(mal, MAL_RXCASR,
get_mal_dcrn(mal, MAL_RXCASR) | MAL_CHAN_MASK(channel));
spin_unlock_irqrestore(&mal->lock, flags);
}
void mal_disable_rx_channel(struct mal_instance *mal, int channel)
{
set_mal_dcrn(mal, MAL_RXCARR, MAL_CHAN_MASK(channel));
MAL_DBG(mal, "disable_rx(%d)" NL, channel);
}
void mal_poll_add(struct mal_instance *mal, struct mal_commac *commac)
{
unsigned long flags;
spin_lock_irqsave(&mal->lock, flags);
MAL_DBG(mal, "poll_add(%p)" NL, commac);
/* starts disabled */
set_bit(MAL_COMMAC_POLL_DISABLED, &commac->flags);
list_add_tail(&commac->poll_list, &mal->poll_list);
spin_unlock_irqrestore(&mal->lock, flags);
}
void mal_poll_del(struct mal_instance *mal, struct mal_commac *commac)
{
unsigned long flags;
spin_lock_irqsave(&mal->lock, flags);
MAL_DBG(mal, "poll_del(%p)" NL, commac);
list_del(&commac->poll_list);
spin_unlock_irqrestore(&mal->lock, flags);
}
/* synchronized by mal_poll() */
static inline void mal_enable_eob_irq(struct mal_instance *mal)
{
MAL_DBG2(mal, "enable_irq" NL);
// XXX might want to cache MAL_CFG as the DCR read can be slooooow
set_mal_dcrn(mal, MAL_CFG, get_mal_dcrn(mal, MAL_CFG) | MAL_CFG_EOPIE);
}
/* synchronized by __LINK_STATE_RX_SCHED bit in ndev->state */
static inline void mal_disable_eob_irq(struct mal_instance *mal)
{
// XXX might want to cache MAL_CFG as the DCR read can be slooooow
set_mal_dcrn(mal, MAL_CFG, get_mal_dcrn(mal, MAL_CFG) & ~MAL_CFG_EOPIE);
MAL_DBG2(mal, "disable_irq" NL);
}
static irqreturn_t mal_serr(int irq, void *dev_instance)
{
struct mal_instance *mal = dev_instance;
u32 esr = get_mal_dcrn(mal, MAL_ESR);
/* Clear the error status register */
set_mal_dcrn(mal, MAL_ESR, esr);
MAL_DBG(mal, "SERR %08x" NL, esr);
if (esr & MAL_ESR_EVB) {
if (esr & MAL_ESR_DE) {
/* We ignore Descriptor error,
* TXDE or RXDE interrupt will be generated anyway.
*/
return IRQ_HANDLED;
}
if (esr & MAL_ESR_PEIN) {
/* PLB error, it's probably buggy hardware or
* incorrect physical address in BD (i.e. bug)
*/
if (net_ratelimit())
printk(KERN_ERR
"mal%d: system error, "
"PLB (ESR = 0x%08x)\n",
mal->index, esr);
return IRQ_HANDLED;
}
/* OPB error, it's probably buggy hardware or incorrect
* EBC setup
*/
if (net_ratelimit())
printk(KERN_ERR
"mal%d: system error, OPB (ESR = 0x%08x)\n",
mal->index, esr);
}
return IRQ_HANDLED;
}
static inline void mal_schedule_poll(struct mal_instance *mal)
{
if (likely(netif_rx_schedule_prep(&mal->poll_dev))) {
MAL_DBG2(mal, "schedule_poll" NL);
mal_disable_eob_irq(mal);
__netif_rx_schedule(&mal->poll_dev);
} else
MAL_DBG2(mal, "already in poll" NL);
}
static irqreturn_t mal_txeob(int irq, void *dev_instance)
{
struct mal_instance *mal = dev_instance;
u32 r = get_mal_dcrn(mal, MAL_TXEOBISR);
MAL_DBG2(mal, "txeob %08x" NL, r);
mal_schedule_poll(mal);
set_mal_dcrn(mal, MAL_TXEOBISR, r);
return IRQ_HANDLED;
}
static irqreturn_t mal_rxeob(int irq, void *dev_instance)
{
struct mal_instance *mal = dev_instance;
u32 r = get_mal_dcrn(mal, MAL_RXEOBISR);
MAL_DBG2(mal, "rxeob %08x" NL, r);
mal_schedule_poll(mal);
set_mal_dcrn(mal, MAL_RXEOBISR, r);
return IRQ_HANDLED;
}
static irqreturn_t mal_txde(int irq, void *dev_instance)
{
struct mal_instance *mal = dev_instance;
u32 deir = get_mal_dcrn(mal, MAL_TXDEIR);
set_mal_dcrn(mal, MAL_TXDEIR, deir);
MAL_DBG(mal, "txde %08x" NL, deir);
if (net_ratelimit())
printk(KERN_ERR
"mal%d: TX descriptor error (TXDEIR = 0x%08x)\n",
mal->index, deir);
return IRQ_HANDLED;
}
static irqreturn_t mal_rxde(int irq, void *dev_instance)
{
struct mal_instance *mal = dev_instance;
struct list_head *l;
u32 deir = get_mal_dcrn(mal, MAL_RXDEIR);
MAL_DBG(mal, "rxde %08x" NL, deir);
list_for_each(l, &mal->list) {
struct mal_commac *mc = list_entry(l, struct mal_commac, list);
if (deir & mc->rx_chan_mask) {
set_bit(MAL_COMMAC_RX_STOPPED, &mc->flags);
mc->ops->rxde(mc->dev);
}
}
mal_schedule_poll(mal);
set_mal_dcrn(mal, MAL_RXDEIR, deir);
return IRQ_HANDLED;
}
void mal_poll_disable(struct mal_instance *mal, struct mal_commac *commac)
{
/* Spinlock-type semantics: only one caller disable poll at a time */
while (test_and_set_bit(MAL_COMMAC_POLL_DISABLED, &commac->flags))
msleep(1);
/* Synchronize with the MAL NAPI poller. */
while (test_bit(__LINK_STATE_RX_SCHED, &mal->poll_dev.state))
msleep(1);
}
void mal_poll_enable(struct mal_instance *mal, struct mal_commac *commac)
{
smp_wmb();
clear_bit(MAL_COMMAC_POLL_DISABLED, &commac->flags);
// XXX might want to kick a poll now...
}
static int mal_poll(struct net_device *ndev, int *budget)
{
struct mal_instance *mal = netdev_priv(ndev);
struct list_head *l;
int rx_work_limit = min(ndev->quota, *budget), received = 0, done;
unsigned long flags;
MAL_DBG2(mal, "poll(%d) %d ->" NL, *budget,
rx_work_limit);
again:
/* Process TX skbs */
list_for_each(l, &mal->poll_list) {
struct mal_commac *mc =
list_entry(l, struct mal_commac, poll_list);
mc->ops->poll_tx(mc->dev);
}
/* Process RX skbs.
*
* We _might_ need something more smart here to enforce polling
* fairness.
*/
list_for_each(l, &mal->poll_list) {
struct mal_commac *mc =
list_entry(l, struct mal_commac, poll_list);
int n;
if (unlikely(test_bit(MAL_COMMAC_POLL_DISABLED, &mc->flags)))
continue;
n = mc->ops->poll_rx(mc->dev, rx_work_limit);
if (n) {
received += n;
rx_work_limit -= n;
if (rx_work_limit <= 0) {
done = 0;
// XXX What if this is the last one ?
goto more_work;
}
}
}
/* We need to disable IRQs to protect from RXDE IRQ here */
spin_lock_irqsave(&mal->lock, flags);
__netif_rx_complete(ndev);
mal_enable_eob_irq(mal);
spin_unlock_irqrestore(&mal->lock, flags);
done = 1;
/* Check for "rotting" packet(s) */
list_for_each(l, &mal->poll_list) {
struct mal_commac *mc =
list_entry(l, struct mal_commac, poll_list);
if (unlikely(test_bit(MAL_COMMAC_POLL_DISABLED, &mc->flags)))
continue;
if (unlikely(mc->ops->peek_rx(mc->dev) ||
test_bit(MAL_COMMAC_RX_STOPPED, &mc->flags))) {
MAL_DBG2(mal, "rotting packet" NL);
if (netif_rx_reschedule(ndev, received))
mal_disable_eob_irq(mal);
else
MAL_DBG2(mal, "already in poll list" NL);
if (rx_work_limit > 0)
goto again;
else
goto more_work;
}
mc->ops->poll_tx(mc->dev);
}
more_work:
ndev->quota -= received;
*budget -= received;
MAL_DBG2(mal, "poll() %d <- %d" NL, *budget,
done ? 0 : 1);
return done ? 0 : 1;
}
static void mal_reset(struct mal_instance *mal)
{
int n = 10;
MAL_DBG(mal, "reset" NL);
set_mal_dcrn(mal, MAL_CFG, MAL_CFG_SR);
/* Wait for reset to complete (1 system clock) */
while ((get_mal_dcrn(mal, MAL_CFG) & MAL_CFG_SR) && n)
--n;
if (unlikely(!n))
printk(KERN_ERR "mal%d: reset timeout\n", mal->index);
}
int mal_get_regs_len(struct mal_instance *mal)
{
return sizeof(struct emac_ethtool_regs_subhdr) +
sizeof(struct mal_regs);
}
void *mal_dump_regs(struct mal_instance *mal, void *buf)
{
struct emac_ethtool_regs_subhdr *hdr = buf;
struct mal_regs *regs = (struct mal_regs *)(hdr + 1);
int i;
hdr->version = mal->version;
hdr->index = mal->index;
regs->tx_count = mal->num_tx_chans;
regs->rx_count = mal->num_rx_chans;
regs->cfg = get_mal_dcrn(mal, MAL_CFG);
regs->esr = get_mal_dcrn(mal, MAL_ESR);
regs->ier = get_mal_dcrn(mal, MAL_IER);
regs->tx_casr = get_mal_dcrn(mal, MAL_TXCASR);
regs->tx_carr = get_mal_dcrn(mal, MAL_TXCARR);
regs->tx_eobisr = get_mal_dcrn(mal, MAL_TXEOBISR);
regs->tx_deir = get_mal_dcrn(mal, MAL_TXDEIR);
regs->rx_casr = get_mal_dcrn(mal, MAL_RXCASR);
regs->rx_carr = get_mal_dcrn(mal, MAL_RXCARR);
regs->rx_eobisr = get_mal_dcrn(mal, MAL_RXEOBISR);
regs->rx_deir = get_mal_dcrn(mal, MAL_RXDEIR);
for (i = 0; i < regs->tx_count; ++i)
regs->tx_ctpr[i] = get_mal_dcrn(mal, MAL_TXCTPR(i));
for (i = 0; i < regs->rx_count; ++i) {
regs->rx_ctpr[i] = get_mal_dcrn(mal, MAL_RXCTPR(i));
regs->rcbs[i] = get_mal_dcrn(mal, MAL_RCBS(i));
}
return regs + 1;
}
static int __devinit mal_probe(struct of_device *ofdev,
const struct of_device_id *match)
{
struct mal_instance *mal;
int err = 0, i, bd_size;
int index = mal_count++;
const u32 *prop;
u32 cfg;
mal = kzalloc(sizeof(struct mal_instance), GFP_KERNEL);
if (!mal) {
printk(KERN_ERR
"mal%d: out of memory allocating MAL structure!\n",
index);
return -ENOMEM;
}
mal->index = index;
mal->ofdev = ofdev;
mal->version = of_device_is_compatible(ofdev->node, "ibm,mcmal2") ? 2 : 1;
MAL_DBG(mal, "probe" NL);
prop = of_get_property(ofdev->node, "num-tx-chans", NULL);
if (prop == NULL) {
printk(KERN_ERR
"mal%d: can't find MAL num-tx-chans property!\n",
index);
err = -ENODEV;
goto fail;
}
mal->num_tx_chans = prop[0];
prop = of_get_property(ofdev->node, "num-rx-chans", NULL);
if (prop == NULL) {
printk(KERN_ERR
"mal%d: can't find MAL num-rx-chans property!\n",
index);
err = -ENODEV;
goto fail;
}
mal->num_rx_chans = prop[0];
mal->dcr_base = dcr_resource_start(ofdev->node, 0);
if (mal->dcr_base == 0) {
printk(KERN_ERR
"mal%d: can't find DCR resource!\n", index);
err = -ENODEV;
goto fail;
}
mal->dcr_host = dcr_map(ofdev->node, mal->dcr_base, 0x100);
if (!DCR_MAP_OK(mal->dcr_host)) {
printk(KERN_ERR
"mal%d: failed to map DCRs !\n", index);
err = -ENODEV;
goto fail;
}
mal->txeob_irq = irq_of_parse_and_map(ofdev->node, 0);
mal->rxeob_irq = irq_of_parse_and_map(ofdev->node, 1);
mal->serr_irq = irq_of_parse_and_map(ofdev->node, 2);
mal->txde_irq = irq_of_parse_and_map(ofdev->node, 3);
mal->rxde_irq = irq_of_parse_and_map(ofdev->node, 4);
if (mal->txeob_irq == NO_IRQ || mal->rxeob_irq == NO_IRQ ||
mal->serr_irq == NO_IRQ || mal->txde_irq == NO_IRQ ||
mal->rxde_irq == NO_IRQ) {
printk(KERN_ERR
"mal%d: failed to map interrupts !\n", index);
err = -ENODEV;
goto fail_unmap;
}
INIT_LIST_HEAD(&mal->poll_list);
set_bit(__LINK_STATE_START, &mal->poll_dev.state);
mal->poll_dev.weight = CONFIG_IBM_NEW_EMAC_POLL_WEIGHT;
mal->poll_dev.poll = mal_poll;
mal->poll_dev.priv = mal;
atomic_set(&mal->poll_dev.refcnt, 1);
INIT_LIST_HEAD(&mal->list);
spin_lock_init(&mal->lock);
/* Load power-on reset defaults */
mal_reset(mal);
/* Set the MAL configuration register */
cfg = (mal->version == 2) ? MAL2_CFG_DEFAULT : MAL1_CFG_DEFAULT;
cfg |= MAL_CFG_PLBB | MAL_CFG_OPBBL | MAL_CFG_LEA;
/* Current Axon is not happy with priority being non-0, it can
* deadlock, fix it up here
*/
if (of_device_is_compatible(ofdev->node, "ibm,mcmal-axon"))
cfg &= ~(MAL2_CFG_RPP_10 | MAL2_CFG_WPP_10);
/* Apply configuration */
set_mal_dcrn(mal, MAL_CFG, cfg);
/* Allocate space for BD rings */
BUG_ON(mal->num_tx_chans <= 0 || mal->num_tx_chans > 32);
BUG_ON(mal->num_rx_chans <= 0 || mal->num_rx_chans > 32);
bd_size = sizeof(struct mal_descriptor) *
(NUM_TX_BUFF * mal->num_tx_chans +
NUM_RX_BUFF * mal->num_rx_chans);
mal->bd_virt =
dma_alloc_coherent(&ofdev->dev, bd_size, &mal->bd_dma,
GFP_KERNEL);
if (mal->bd_virt == NULL) {
printk(KERN_ERR
"mal%d: out of memory allocating RX/TX descriptors!\n",
index);
err = -ENOMEM;
goto fail_unmap;
}
memset(mal->bd_virt, 0, bd_size);
for (i = 0; i < mal->num_tx_chans; ++i)
set_mal_dcrn(mal, MAL_TXCTPR(i), mal->bd_dma +
sizeof(struct mal_descriptor) *
mal_tx_bd_offset(mal, i));
for (i = 0; i < mal->num_rx_chans; ++i)
set_mal_dcrn(mal, MAL_RXCTPR(i), mal->bd_dma +
sizeof(struct mal_descriptor) *
mal_rx_bd_offset(mal, i));
err = request_irq(mal->serr_irq, mal_serr, 0, "MAL SERR", mal);
if (err)
goto fail2;
err = request_irq(mal->txde_irq, mal_txde, 0, "MAL TX DE", mal);
if (err)
goto fail3;
err = request_irq(mal->txeob_irq, mal_txeob, 0, "MAL TX EOB", mal);
if (err)
goto fail4;
err = request_irq(mal->rxde_irq, mal_rxde, 0, "MAL RX DE", mal);
if (err)
goto fail5;
err = request_irq(mal->rxeob_irq, mal_rxeob, 0, "MAL RX EOB", mal);
if (err)
goto fail6;
/* Enable all MAL SERR interrupt sources */
if (mal->version == 2)
set_mal_dcrn(mal, MAL_IER, MAL2_IER_EVENTS);
else
set_mal_dcrn(mal, MAL_IER, MAL1_IER_EVENTS);
/* Enable EOB interrupt */
mal_enable_eob_irq(mal);
printk(KERN_INFO
"MAL v%d %s, %d TX channels, %d RX channels\n",
mal->version, ofdev->node->full_name,
mal->num_tx_chans, mal->num_rx_chans);
/* Advertise this instance to the rest of the world */
wmb();
dev_set_drvdata(&ofdev->dev, mal);
mal_dbg_register(mal);
return 0;
fail6:
free_irq(mal->rxde_irq, mal);
fail5:
free_irq(mal->txeob_irq, mal);
fail4:
free_irq(mal->txde_irq, mal);
fail3:
free_irq(mal->serr_irq, mal);
fail2:
dma_free_coherent(&ofdev->dev, bd_size, mal->bd_virt, mal->bd_dma);
fail_unmap:
dcr_unmap(mal->dcr_host, mal->dcr_base, 0x100);
fail:
kfree(mal);
return err;
}
static int __devexit mal_remove(struct of_device *ofdev)
{
struct mal_instance *mal = dev_get_drvdata(&ofdev->dev);
MAL_DBG(mal, "remove" NL);
/* Syncronize with scheduled polling,
stolen from net/core/dev.c:dev_close()
*/
clear_bit(__LINK_STATE_START, &mal->poll_dev.state);
netif_poll_disable(&mal->poll_dev);
if (!list_empty(&mal->list)) {
/* This is *very* bad */
printk(KERN_EMERG
"mal%d: commac list is not empty on remove!\n",
mal->index);
WARN_ON(1);
}
dev_set_drvdata(&ofdev->dev, NULL);
free_irq(mal->serr_irq, mal);
free_irq(mal->txde_irq, mal);
free_irq(mal->txeob_irq, mal);
free_irq(mal->rxde_irq, mal);
free_irq(mal->rxeob_irq, mal);
mal_reset(mal);
mal_dbg_unregister(mal);
dma_free_coherent(&ofdev->dev,
sizeof(struct mal_descriptor) *
(NUM_TX_BUFF * mal->num_tx_chans +
NUM_RX_BUFF * mal->num_rx_chans), mal->bd_virt,
mal->bd_dma);
kfree(mal);
return 0;
}
static struct of_device_id mal_platform_match[] =
{
{
.compatible = "ibm,mcmal",
},
{
.compatible = "ibm,mcmal2",
},
/* Backward compat */
{
.type = "mcmal-dma",
.compatible = "ibm,mcmal",
},
{
.type = "mcmal-dma",
.compatible = "ibm,mcmal2",
},
{},
};
static struct of_platform_driver mal_of_driver = {
.name = "mcmal",
.match_table = mal_platform_match,
.probe = mal_probe,
.remove = mal_remove,
};
int __init mal_init(void)
{
return of_register_platform_driver(&mal_of_driver);
}
void mal_exit(void)
{
of_unregister_platform_driver(&mal_of_driver);
}