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linux/drivers/gpu/drm/nouveau/nouveau_i2c.c
Ben Skeggs f553b79c03 drm/nouveau/i2c: handle bit-banging ourselves 
i2c-algo-bit doesn't actually work very well on one card I have access to
(NVS 300), random single-bit errors occur most of the time - what we're
doing now is closer to what xf86i2c.c does.

The original plan was to figure out why i2c-algo-bit fails on the NVS 300,
and fix it.  However, while investigating I discovered i2c-algo-bit calls
cond_resched(), which makes it a bad idea for us to be using as we execute
VBIOS scripts from a tasklet, and there may very well be i2c transfers as
a result.

So, since I already wrote this code in userspace to track down the NVS 300
bug, and it's not really much code - lets use it.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2011-12-21 19:01:41 +10:00

551 lines
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/*
* Copyright 2009 Red Hat Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Authors: Ben Skeggs
*/
#include <linux/module.h>
#include "drmP.h"
#include "nouveau_drv.h"
#include "nouveau_i2c.h"
#include "nouveau_hw.h"
#define T_TIMEOUT 2200000
#define T_RISEFALL 1000
#define T_HOLD 5000
static void
i2c_drive_scl(void *data, int state)
{
struct nouveau_i2c_chan *port = data;
if (port->type == 0) {
u8 val = NVReadVgaCrtc(port->dev, 0, port->drive);
if (state) val |= 0x20;
else val &= 0xdf;
NVWriteVgaCrtc(port->dev, 0, port->drive, val | 0x01);
} else
if (port->type == 4) {
nv_mask(port->dev, port->drive, 0x2f, state ? 0x21 : 0x01);
} else
if (port->type == 5) {
if (state) port->state |= 0x01;
else port->state &= 0xfe;
nv_wr32(port->dev, port->drive, 4 | port->state);
}
}
static void
i2c_drive_sda(void *data, int state)
{
struct nouveau_i2c_chan *port = data;
if (port->type == 0) {
u8 val = NVReadVgaCrtc(port->dev, 0, port->drive);
if (state) val |= 0x10;
else val &= 0xef;
NVWriteVgaCrtc(port->dev, 0, port->drive, val | 0x01);
} else
if (port->type == 4) {
nv_mask(port->dev, port->drive, 0x1f, state ? 0x11 : 0x01);
} else
if (port->type == 5) {
if (state) port->state |= 0x02;
else port->state &= 0xfd;
nv_wr32(port->dev, port->drive, 4 | port->state);
}
}
static int
i2c_sense_scl(void *data)
{
struct nouveau_i2c_chan *port = data;
struct drm_nouveau_private *dev_priv = port->dev->dev_private;
if (port->type == 0) {
return !!(NVReadVgaCrtc(port->dev, 0, port->sense) & 0x04);
} else
if (port->type == 4) {
return !!(nv_rd32(port->dev, port->sense) & 0x00040000);
} else
if (port->type == 5) {
if (dev_priv->card_type < NV_D0)
return !!(nv_rd32(port->dev, port->sense) & 0x01);
else
return !!(nv_rd32(port->dev, port->sense) & 0x10);
}
return 0;
}
static int
i2c_sense_sda(void *data)
{
struct nouveau_i2c_chan *port = data;
struct drm_nouveau_private *dev_priv = port->dev->dev_private;
if (port->type == 0) {
return !!(NVReadVgaCrtc(port->dev, 0, port->sense) & 0x08);
} else
if (port->type == 4) {
return !!(nv_rd32(port->dev, port->sense) & 0x00080000);
} else
if (port->type == 5) {
if (dev_priv->card_type < NV_D0)
return !!(nv_rd32(port->dev, port->sense) & 0x02);
else
return !!(nv_rd32(port->dev, port->sense) & 0x20);
}
return 0;
}
static void
i2c_delay(struct nouveau_i2c_chan *port, u32 nsec)
{
udelay((nsec + 500) / 1000);
}
static bool
i2c_raise_scl(struct nouveau_i2c_chan *port)
{
u32 timeout = T_TIMEOUT / T_RISEFALL;
i2c_drive_scl(port, 1);
do {
i2c_delay(port, T_RISEFALL);
} while (!i2c_sense_scl(port) && --timeout);
return timeout != 0;
}
static int
i2c_start(struct nouveau_i2c_chan *port)
{
int ret = 0;
port->state = i2c_sense_scl(port);
port->state |= i2c_sense_sda(port) << 1;
if (port->state != 3) {
i2c_drive_scl(port, 0);
i2c_drive_sda(port, 1);
if (!i2c_raise_scl(port))
ret = -EBUSY;
}
i2c_drive_sda(port, 0);
i2c_delay(port, T_HOLD);
i2c_drive_scl(port, 0);
i2c_delay(port, T_HOLD);
return ret;
}
static void
i2c_stop(struct nouveau_i2c_chan *port)
{
i2c_drive_scl(port, 0);
i2c_drive_sda(port, 0);
i2c_delay(port, T_RISEFALL);
i2c_drive_scl(port, 1);
i2c_delay(port, T_HOLD);
i2c_drive_sda(port, 1);
i2c_delay(port, T_HOLD);
}
static int
i2c_bitw(struct nouveau_i2c_chan *port, int sda)
{
i2c_drive_sda(port, sda);
i2c_delay(port, T_RISEFALL);
if (!i2c_raise_scl(port))
return -ETIMEDOUT;
i2c_delay(port, T_HOLD);
i2c_drive_scl(port, 0);
i2c_delay(port, T_HOLD);
return 0;
}
static int
i2c_bitr(struct nouveau_i2c_chan *port)
{
int sda;
i2c_drive_sda(port, 1);
i2c_delay(port, T_RISEFALL);
if (!i2c_raise_scl(port))
return -ETIMEDOUT;
i2c_delay(port, T_HOLD);
sda = i2c_sense_sda(port);
i2c_drive_scl(port, 0);
i2c_delay(port, T_HOLD);
return sda;
}
static int
i2c_get_byte(struct nouveau_i2c_chan *port, u8 *byte, bool last)
{
int i, bit;
*byte = 0;
for (i = 7; i >= 0; i--) {
bit = i2c_bitr(port);
if (bit < 0)
return bit;
*byte |= bit << i;
}
return i2c_bitw(port, last ? 1 : 0);
}
static int
i2c_put_byte(struct nouveau_i2c_chan *port, u8 byte)
{
int i, ret;
for (i = 7; i >= 0; i--) {
ret = i2c_bitw(port, !!(byte & (1 << i)));
if (ret < 0)
return ret;
}
ret = i2c_bitr(port);
if (ret == 1) /* nack */
ret = -EIO;
return ret;
}
static int
i2c_addr(struct nouveau_i2c_chan *port, struct i2c_msg *msg)
{
u32 addr = msg->addr << 1;
if (msg->flags & I2C_M_RD)
addr |= 1;
return i2c_put_byte(port, addr);
}
static int
i2c_bit_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
struct nouveau_i2c_chan *port = (struct nouveau_i2c_chan *)adap;
struct i2c_msg *msg = msgs;
int ret = 0, mcnt = num;
while (!ret && mcnt--) {
u8 remaining = msg->len;
u8 *ptr = msg->buf;
ret = i2c_start(port);
if (ret == 0)
ret = i2c_addr(port, msg);
if (msg->flags & I2C_M_RD) {
while (!ret && remaining--)
ret = i2c_get_byte(port, ptr++, !remaining);
} else {
while (!ret && remaining--)
ret = i2c_put_byte(port, *ptr++);
}
msg++;
}
i2c_stop(port);
return (ret < 0) ? ret : num;
}
static u32
i2c_bit_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
const struct i2c_algorithm i2c_bit_algo = {
.master_xfer = i2c_bit_xfer,
.functionality = i2c_bit_func
};
static const uint32_t nv50_i2c_port[] = {
0x00e138, 0x00e150, 0x00e168, 0x00e180,
0x00e254, 0x00e274, 0x00e764, 0x00e780,
0x00e79c, 0x00e7b8
};
static u8 *
i2c_table(struct drm_device *dev, u8 *version)
{
u8 *dcb = dcb_table(dev), *i2c = NULL;
if (dcb) {
if (dcb[0] >= 0x15)
i2c = ROMPTR(dev, dcb[2]);
if (dcb[0] >= 0x30)
i2c = ROMPTR(dev, dcb[4]);
}
/* early revisions had no version number, use dcb version */
if (i2c) {
*version = dcb[0];
if (*version >= 0x30)
*version = i2c[0];
}
return i2c;
}
int
nouveau_i2c_init(struct drm_device *dev)
{
struct drm_nouveau_private *dev_priv = dev->dev_private;
struct nvbios *bios = &dev_priv->vbios;
struct nouveau_i2c_chan *port;
u8 *i2c, *entry, legacy[2][4] = {};
u8 version, entries, recordlen;
int ret, i;
INIT_LIST_HEAD(&dev_priv->i2c_ports);
i2c = i2c_table(dev, &version);
if (!i2c) {
u8 *bmp = &bios->data[bios->offset];
if (bios->type != NVBIOS_BMP)
return -ENODEV;
legacy[0][0] = NV_CIO_CRE_DDC_WR__INDEX;
legacy[0][1] = NV_CIO_CRE_DDC_STATUS__INDEX;
legacy[1][0] = NV_CIO_CRE_DDC0_WR__INDEX;
legacy[1][1] = NV_CIO_CRE_DDC0_STATUS__INDEX;
/* BMP (from v4.0) has i2c info in the structure, it's in a
* fixed location on earlier VBIOS
*/
if (bmp[5] < 4)
i2c = &bios->data[0x48];
else
i2c = &bmp[0x36];
if (i2c[4]) legacy[0][0] = i2c[4];
if (i2c[5]) legacy[0][1] = i2c[5];
if (i2c[6]) legacy[1][0] = i2c[6];
if (i2c[7]) legacy[1][1] = i2c[7];
}
if (i2c && version >= 0x30) {
entry = i2c[1] + i2c;
entries = i2c[2];
recordlen = i2c[3];
} else
if (i2c) {
entry = i2c;
entries = 16;
recordlen = 4;
} else {
entry = legacy[0];
entries = 2;
recordlen = 4;
}
for (i = 0; i < entries; i++, entry += recordlen) {
port = kzalloc(sizeof(*port), GFP_KERNEL);
if (port == NULL) {
nouveau_i2c_fini(dev);
return -ENOMEM;
}
port->type = entry[3];
if (version < 0x30) {
port->type &= 0x07;
if (port->type == 0x07)
port->type = 0xff;
}
if (port->type == 0xff) {
kfree(port);
continue;
}
switch (port->type) {
case 0: /* NV04:NV50 */
port->drive = entry[0];
port->sense = entry[1];
port->adapter.algo = &i2c_bit_algo;
break;
case 4: /* NV4E */
port->drive = 0x600800 + entry[1];
port->sense = port->drive;
port->adapter.algo = &i2c_bit_algo;
break;
case 5: /* NV50- */
port->drive = entry[0] & 0x0f;
if (dev_priv->card_type < NV_D0) {
if (port->drive >= ARRAY_SIZE(nv50_i2c_port))
break;
port->drive = nv50_i2c_port[port->drive];
port->sense = port->drive;
} else {
port->drive = 0x00d014 + (port->drive * 0x20);
port->sense = port->drive;
}
port->adapter.algo = &i2c_bit_algo;
break;
case 6: /* NV50- DP AUX */
port->drive = entry[0];
port->sense = port->drive;
port->adapter.algo = &nouveau_dp_i2c_algo;
break;
default:
break;
}
if (!port->adapter.algo) {
NV_ERROR(dev, "I2C%d: type %d index %x/%x unknown\n",
i, port->type, port->drive, port->sense);
kfree(port);
continue;
}
snprintf(port->adapter.name, sizeof(port->adapter.name),
"nouveau-%s-%d", pci_name(dev->pdev), i);
port->adapter.owner = THIS_MODULE;
port->adapter.dev.parent = &dev->pdev->dev;
port->dev = dev;
port->index = i;
port->dcb = ROM32(entry[0]);
i2c_set_adapdata(&port->adapter, i2c);
ret = i2c_add_adapter(&port->adapter);
if (ret) {
NV_ERROR(dev, "I2C%d: failed register: %d\n", i, ret);
kfree(port);
continue;
}
list_add_tail(&port->head, &dev_priv->i2c_ports);
}
return 0;
}
void
nouveau_i2c_fini(struct drm_device *dev)
{
struct drm_nouveau_private *dev_priv = dev->dev_private;
struct nouveau_i2c_chan *port, *tmp;
list_for_each_entry_safe(port, tmp, &dev_priv->i2c_ports, head) {
i2c_del_adapter(&port->adapter);
kfree(port);
}
}
struct nouveau_i2c_chan *
nouveau_i2c_find(struct drm_device *dev, u8 index)
{
struct drm_nouveau_private *dev_priv = dev->dev_private;
struct nouveau_i2c_chan *port;
if (index == NV_I2C_DEFAULT(0) ||
index == NV_I2C_DEFAULT(1)) {
u8 version, *i2c = i2c_table(dev, &version);
if (i2c && version >= 0x30) {
if (index == NV_I2C_DEFAULT(0))
index = (i2c[4] & 0x0f);
else
index = (i2c[4] & 0xf0) >> 4;
} else {
index = 2;
}
}
list_for_each_entry(port, &dev_priv->i2c_ports, head) {
if (port->index == index)
break;
}
if (&port->head == &dev_priv->i2c_ports)
return NULL;
if (dev_priv->card_type >= NV_50 && (port->dcb & 0x00000100)) {
u32 reg = 0x00e500, val;
if (port->type == 6) {
reg += port->drive * 0x50;
val = 0x2002;
} else {
reg += ((port->dcb & 0x1e00) >> 9) * 0x50;
val = 0xe001;
}
/* nfi, but neither auxch or i2c work if it's 1 */
nv_mask(dev, reg + 0x0c, 0x00000001, 0x00000000);
/* nfi, but switches auxch vs normal i2c */
nv_mask(dev, reg + 0x00, 0x0000f003, val);
}
return port;
}
bool
nouveau_probe_i2c_addr(struct nouveau_i2c_chan *i2c, int addr)
{
uint8_t buf[] = { 0 };
struct i2c_msg msgs[] = {
{
.addr = addr,
.flags = 0,
.len = 1,
.buf = buf,
},
{
.addr = addr,
.flags = I2C_M_RD,
.len = 1,
.buf = buf,
}
};
return i2c_transfer(&i2c->adapter, msgs, 2) == 2;
}
int
nouveau_i2c_identify(struct drm_device *dev, const char *what,
struct i2c_board_info *info,
bool (*match)(struct nouveau_i2c_chan *,
struct i2c_board_info *),
int index)
{
struct nouveau_i2c_chan *i2c = nouveau_i2c_find(dev, index);
int i;
if (!i2c) {
NV_DEBUG(dev, "No bus when probing %s on %d\n", what, index);
return -ENODEV;
}
NV_DEBUG(dev, "Probing %ss on I2C bus: %d\n", what, i2c->index);
for (i = 0; info[i].addr; i++) {
if (nouveau_probe_i2c_addr(i2c, info[i].addr) &&
(!match || match(i2c, &info[i]))) {
NV_INFO(dev, "Detected %s: %s\n", what, info[i].type);
return i;
}
}
NV_DEBUG(dev, "No devices found.\n");
return -ENODEV;
}
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