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Fix/Rewrite of the mipsnet driver]
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This is Thiemo's patch.

----- Forwarded message from Thiemo Seufer <ths@networkno.de> -----

From: Thiemo Seufer <ths@networkno.de>
Date: Sat, 17 Nov 2007 22:29:13 +0000
To: netdev@vger.kernel.org
Cc: linux-mips@linux-mips.org, ralf@linux-mips.org
Subject: [PATCH, REPOST] Fix/Rewrite of the mipsnet driver
Content-Type: text/plain; charset=us-ascii

Hello All,

currently the mipsnet driver fails after transmitting a number of
packages because SKBs are allocated but never freed. I fixed that
and coudn't refrain from removing the most egregious warts.

- mipsnet.h folded into mipsnet.c, as it doesn't provide any
  useful external interface.
- Free SKB after transmission.
- Call free_irq in mipsnet_close, to balance the request_irq in
  mipsnet_open.
- Removed duplicate read of rxDataCount.
- Some identifiers are now less verbose.
- Removed dead and/or unnecessarily complex code.
- Code formatting fixes.

Tested on Qemu's mipssim emulation, with this patch it can boot a
Debian NFSroot.

Thiemo

Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Ralf Baechle authored and David S. Miller committed Feb 3, 2008
1 parent ba64f58 commit c800c5c
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Showing 2 changed files with 135 additions and 180 deletions.
203 changes: 135 additions & 68 deletions drivers/net/mipsnet.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,6 @@
* for more details.
*/

#define DEBUG

#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
Expand All @@ -15,11 +13,93 @@
#include <linux/platform_device.h>
#include <asm/mips-boards/simint.h>

#include "mipsnet.h" /* actual device IO mapping */
#define MIPSNET_VERSION "2007-11-17"

/*
* Net status/control block as seen by sw in the core.
*/
struct mipsnet_regs {
/*
* Device info for probing, reads as MIPSNET%d where %d is some
* form of version.
*/
u64 devId; /*0x00 */

#define MIPSNET_VERSION "2005-06-20"
/*
* read only busy flag.
* Set and cleared by the Net Device to indicate that an rx or a tx
* is in progress.
*/
u32 busy; /*0x08 */

#define mipsnet_reg_address(dev, field) (dev->base_addr + field_offset(field))
/*
* Set by the Net Device.
* The device will set it once data has been received.
* The value is the number of bytes that should be read from
* rxDataBuffer. The value will decrease till 0 until all the data
* from rxDataBuffer has been read.
*/
u32 rxDataCount; /*0x0c */
#define MIPSNET_MAX_RXTX_DATACOUNT (1 << 16)

/*
* Settable from the MIPS core, cleared by the Net Device.
* The core should set the number of bytes it wants to send,
* then it should write those bytes of data to txDataBuffer.
* The device will clear txDataCount has been processed (not
* necessarily sent).
*/
u32 txDataCount; /*0x10 */

/*
* Interrupt control
*
* Used to clear the interrupted generated by this dev.
* Write a 1 to clear the interrupt. (except bit31).
*
* Bit0 is set if it was a tx-done interrupt.
* Bit1 is set when new rx-data is available.
* Until this bit is cleared there will be no other RXs.
*
* Bit31 is used for testing, it clears after a read.
* Writing 1 to this bit will cause an interrupt to be generated.
* To clear the test interrupt, write 0 to this register.
*/
u32 interruptControl; /*0x14 */
#define MIPSNET_INTCTL_TXDONE (1u << 0)
#define MIPSNET_INTCTL_RXDONE (1u << 1)
#define MIPSNET_INTCTL_TESTBIT (1u << 31)

/*
* Readonly core-specific interrupt info for the device to signal
* the core. The meaning of the contents of this field might change.
*/
/* XXX: the whole memIntf interrupt scheme is messy: the device
* should have no control what so ever of what VPE/register set is
* being used.
* The MemIntf should only expose interrupt lines, and something in
* the config should be responsible for the line<->core/vpe bindings.
*/
u32 interruptInfo; /*0x18 */

/*
* This is where the received data is read out.
* There is more data to read until rxDataReady is 0.
* Only 1 byte at this regs offset is used.
*/
u32 rxDataBuffer; /*0x1c */

/*
* This is where the data to transmit is written.
* Data should be written for the amount specified in the
* txDataCount register.
* Only 1 byte at this regs offset is used.
*/
u32 txDataBuffer; /*0x20 */
};

#define regaddr(dev, field) \
(dev->base_addr + offsetof(struct mipsnet_regs, field))

static char mipsnet_string[] = "mipsnet";

Expand All @@ -29,32 +109,27 @@ static char mipsnet_string[] = "mipsnet";
static int ioiocpy_frommipsnet(struct net_device *dev, unsigned char *kdata,
int len)
{
uint32_t available_len = inl(mipsnet_reg_address(dev, rxDataCount));

if (available_len < len)
return -EFAULT;

for (; len > 0; len--, kdata++)
*kdata = inb(mipsnet_reg_address(dev, rxDataBuffer));
*kdata = inb(regaddr(dev, rxDataBuffer));

return inl(mipsnet_reg_address(dev, rxDataCount));
return inl(regaddr(dev, rxDataCount));
}

static inline ssize_t mipsnet_put_todevice(struct net_device *dev,
static inline void mipsnet_put_todevice(struct net_device *dev,
struct sk_buff *skb)
{
int count_to_go = skb->len;
char *buf_ptr = skb->data;

outl(skb->len, mipsnet_reg_address(dev, txDataCount));
outl(skb->len, regaddr(dev, txDataCount));

for (; count_to_go; buf_ptr++, count_to_go--)
outb(*buf_ptr, mipsnet_reg_address(dev, txDataBuffer));
outb(*buf_ptr, regaddr(dev, txDataBuffer));

dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;

return skb->len;
dev_kfree_skb(skb);
}

static int mipsnet_xmit(struct sk_buff *skb, struct net_device *dev)
Expand All @@ -69,18 +144,20 @@ static int mipsnet_xmit(struct sk_buff *skb, struct net_device *dev)
return 0;
}

static inline ssize_t mipsnet_get_fromdev(struct net_device *dev, size_t count)
static inline ssize_t mipsnet_get_fromdev(struct net_device *dev, size_t len)
{
struct sk_buff *skb;
size_t len = count;

skb = alloc_skb(len + 2, GFP_KERNEL);
if (!len)
return len;

skb = dev_alloc_skb(len + NET_IP_ALIGN);
if (!skb) {
dev->stats.rx_dropped++;
return -ENOMEM;
}

skb_reserve(skb, 2);
skb_reserve(skb, NET_IP_ALIGN);
if (ioiocpy_frommipsnet(dev, skb_put(skb, len), len))
return -EFAULT;

Expand All @@ -92,50 +169,42 @@ static inline ssize_t mipsnet_get_fromdev(struct net_device *dev, size_t count)
dev->stats.rx_packets++;
dev->stats.rx_bytes += len;

return count;
return len;
}

static irqreturn_t mipsnet_interrupt(int irq, void *dev_id)
{
struct net_device *dev = dev_id;

irqreturn_t retval = IRQ_NONE;
uint64_t interruptFlags;

if (irq == dev->irq) {
retval = IRQ_HANDLED;

interruptFlags =
inl(mipsnet_reg_address(dev, interruptControl));

if (interruptFlags & MIPSNET_INTCTL_TXDONE) {
outl(MIPSNET_INTCTL_TXDONE,
mipsnet_reg_address(dev, interruptControl));
/* only one packet at a time, we are done. */
netif_wake_queue(dev);
} else if (interruptFlags & MIPSNET_INTCTL_RXDONE) {
mipsnet_get_fromdev(dev,
inl(mipsnet_reg_address(dev, rxDataCount)));
outl(MIPSNET_INTCTL_RXDONE,
mipsnet_reg_address(dev, interruptControl));

} else if (interruptFlags & MIPSNET_INTCTL_TESTBIT) {
/*
* TESTBIT is cleared on read.
* And takes effect after a write with 0
*/
outl(0, mipsnet_reg_address(dev, interruptControl));
} else {
/* Maybe shared IRQ, just ignore, no clearing. */
retval = IRQ_NONE;
}

} else {
printk(KERN_INFO "%s: %s(): irq %d for unknown device\n",
dev->name, __FUNCTION__, irq);
retval = IRQ_NONE;
u32 int_flags;
irqreturn_t ret = IRQ_NONE;

if (irq != dev->irq)
goto out_badirq;

/* TESTBIT is cleared on read. */
int_flags = inl(regaddr(dev, interruptControl));
if (int_flags & MIPSNET_INTCTL_TESTBIT) {
/* TESTBIT takes effect after a write with 0. */
outl(0, regaddr(dev, interruptControl));
ret = IRQ_HANDLED;
} else if (int_flags & MIPSNET_INTCTL_TXDONE) {
/* Only one packet at a time, we are done. */
dev->stats.tx_packets++;
netif_wake_queue(dev);
outl(MIPSNET_INTCTL_TXDONE,
regaddr(dev, interruptControl));
ret = IRQ_HANDLED;
} else if (int_flags & MIPSNET_INTCTL_RXDONE) {
mipsnet_get_fromdev(dev, inl(regaddr(dev, rxDataCount)));
outl(MIPSNET_INTCTL_RXDONE, regaddr(dev, interruptControl));
ret = IRQ_HANDLED;
}
return retval;
return ret;

out_badirq:
printk(KERN_INFO "%s: %s(): irq %d for unknown device\n",
dev->name, __FUNCTION__, irq);
return ret;
}

static int mipsnet_open(struct net_device *dev)
Expand All @@ -144,26 +213,23 @@ static int mipsnet_open(struct net_device *dev)

err = request_irq(dev->irq, &mipsnet_interrupt,
IRQF_SHARED, dev->name, (void *) dev);

if (err) {
release_region(dev->base_addr, MIPSNET_IO_EXTENT);
release_region(dev->base_addr, sizeof(struct mipsnet_regs));
return err;
}

netif_start_queue(dev);

/* test interrupt handler */
outl(MIPSNET_INTCTL_TESTBIT,
mipsnet_reg_address(dev, interruptControl));

outl(MIPSNET_INTCTL_TESTBIT, regaddr(dev, interruptControl));

return 0;
}

static int mipsnet_close(struct net_device *dev)
{
netif_stop_queue(dev);

free_irq(dev->irq, dev);
return 0;
}

Expand Down Expand Up @@ -194,10 +260,11 @@ static int __init mipsnet_probe(struct device *dev)
*/
netdev->base_addr = 0x4200;
netdev->irq = MIPS_CPU_IRQ_BASE + MIPSCPU_INT_MB0 +
inl(mipsnet_reg_address(netdev, interruptInfo));
inl(regaddr(netdev, interruptInfo));

/* Get the io region now, get irq on open() */
if (!request_region(netdev->base_addr, MIPSNET_IO_EXTENT, "mipsnet")) {
if (!request_region(netdev->base_addr, sizeof(struct mipsnet_regs),
"mipsnet")) {
err = -EBUSY;
goto out_free_netdev;
}
Expand All @@ -217,7 +284,7 @@ static int __init mipsnet_probe(struct device *dev)
return 0;

out_free_region:
release_region(netdev->base_addr, MIPSNET_IO_EXTENT);
release_region(netdev->base_addr, sizeof(struct mipsnet_regs));

out_free_netdev:
free_netdev(netdev);
Expand All @@ -231,7 +298,7 @@ static int __devexit mipsnet_device_remove(struct device *device)
struct net_device *dev = dev_get_drvdata(device);

unregister_netdev(dev);
release_region(dev->base_addr, MIPSNET_IO_EXTENT);
release_region(dev->base_addr, sizeof(struct mipsnet_regs));
free_netdev(dev);
dev_set_drvdata(device, NULL);

Expand Down
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