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u-boot/drivers/i2c/designware_i2c.c
Marek Vasut b03380805b i2c: designware: Avoid overwriting the cmd_data register 
Make sure the driver writes the cmd_data register only once per
read transfer instead of doing so potentially repeatedly.

In case the read transfer didn't finish quickly enough, the loop
in the driver code would spin fast enough to write the same value
into the cmd_data register again before re-checking whether the
transfer completed, which would cause another spurious read transfer
on the bus.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefan Roese <sr@denx.de>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Chin Liang See <clsee@altera.com>
2016-10-24 18:15:47 +02:00

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/*
* (C) Copyright 2009
* Vipin Kumar, ST Micoelectronics, vipin.kumar@st.com.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <i2c.h>
#include <pci.h>
#include <asm/io.h>
#include "designware_i2c.h"
struct dw_scl_sda_cfg {
u32 ss_hcnt;
u32 fs_hcnt;
u32 ss_lcnt;
u32 fs_lcnt;
u32 sda_hold;
};
#ifdef CONFIG_X86
/* BayTrail HCNT/LCNT/SDA hold time */
static struct dw_scl_sda_cfg byt_config = {
.ss_hcnt = 0x200,
.fs_hcnt = 0x55,
.ss_lcnt = 0x200,
.fs_lcnt = 0x99,
.sda_hold = 0x6,
};
#endif
struct dw_i2c {
struct i2c_regs *regs;
struct dw_scl_sda_cfg *scl_sda_cfg;
};
#ifdef CONFIG_SYS_I2C_DW_ENABLE_STATUS_UNSUPPORTED
static void dw_i2c_enable(struct i2c_regs *i2c_base, bool enable)
{
u32 ena = enable ? IC_ENABLE_0B : 0;
writel(ena, &i2c_base->ic_enable);
}
#else
static void dw_i2c_enable(struct i2c_regs *i2c_base, bool enable)
{
u32 ena = enable ? IC_ENABLE_0B : 0;
int timeout = 100;
do {
writel(ena, &i2c_base->ic_enable);
if ((readl(&i2c_base->ic_enable_status) & IC_ENABLE_0B) == ena)
return;
/*
* Wait 10 times the signaling period of the highest I2C
* transfer supported by the driver (for 400KHz this is
* 25us) as described in the DesignWare I2C databook.
*/
udelay(25);
} while (timeout--);
printf("timeout in %sabling I2C adapter\n", enable ? "en" : "dis");
}
#endif
/*
* i2c_set_bus_speed - Set the i2c speed
* @speed: required i2c speed
*
* Set the i2c speed.
*/
static unsigned int __dw_i2c_set_bus_speed(struct i2c_regs *i2c_base,
struct dw_scl_sda_cfg *scl_sda_cfg,
unsigned int speed)
{
unsigned int cntl;
unsigned int hcnt, lcnt;
int i2c_spd;
if (speed >= I2C_MAX_SPEED)
i2c_spd = IC_SPEED_MODE_MAX;
else if (speed >= I2C_FAST_SPEED)
i2c_spd = IC_SPEED_MODE_FAST;
else
i2c_spd = IC_SPEED_MODE_STANDARD;
/* to set speed cltr must be disabled */
dw_i2c_enable(i2c_base, false);
cntl = (readl(&i2c_base->ic_con) & (~IC_CON_SPD_MSK));
switch (i2c_spd) {
#ifndef CONFIG_X86 /* No High-speed for BayTrail yet */
case IC_SPEED_MODE_MAX:
cntl |= IC_CON_SPD_SS;
if (scl_sda_cfg) {
hcnt = scl_sda_cfg->fs_hcnt;
lcnt = scl_sda_cfg->fs_lcnt;
} else {
hcnt = (IC_CLK * MIN_HS_SCL_HIGHTIME) / NANO_TO_MICRO;
lcnt = (IC_CLK * MIN_HS_SCL_LOWTIME) / NANO_TO_MICRO;
}
writel(hcnt, &i2c_base->ic_hs_scl_hcnt);
writel(lcnt, &i2c_base->ic_hs_scl_lcnt);
break;
#endif
case IC_SPEED_MODE_STANDARD:
cntl |= IC_CON_SPD_SS;
if (scl_sda_cfg) {
hcnt = scl_sda_cfg->ss_hcnt;
lcnt = scl_sda_cfg->ss_lcnt;
} else {
hcnt = (IC_CLK * MIN_SS_SCL_HIGHTIME) / NANO_TO_MICRO;
lcnt = (IC_CLK * MIN_SS_SCL_LOWTIME) / NANO_TO_MICRO;
}
writel(hcnt, &i2c_base->ic_ss_scl_hcnt);
writel(lcnt, &i2c_base->ic_ss_scl_lcnt);
break;
case IC_SPEED_MODE_FAST:
default:
cntl |= IC_CON_SPD_FS;
if (scl_sda_cfg) {
hcnt = scl_sda_cfg->fs_hcnt;
lcnt = scl_sda_cfg->fs_lcnt;
} else {
hcnt = (IC_CLK * MIN_FS_SCL_HIGHTIME) / NANO_TO_MICRO;
lcnt = (IC_CLK * MIN_FS_SCL_LOWTIME) / NANO_TO_MICRO;
}
writel(hcnt, &i2c_base->ic_fs_scl_hcnt);
writel(lcnt, &i2c_base->ic_fs_scl_lcnt);
break;
}
writel(cntl, &i2c_base->ic_con);
/* Configure SDA Hold Time if required */
if (scl_sda_cfg)
writel(scl_sda_cfg->sda_hold, &i2c_base->ic_sda_hold);
/* Enable back i2c now speed set */
dw_i2c_enable(i2c_base, true);
return 0;
}
/*
* i2c_setaddress - Sets the target slave address
* @i2c_addr: target i2c address
*
* Sets the target slave address.
*/
static void i2c_setaddress(struct i2c_regs *i2c_base, unsigned int i2c_addr)
{
/* Disable i2c */
dw_i2c_enable(i2c_base, false);
writel(i2c_addr, &i2c_base->ic_tar);
/* Enable i2c */
dw_i2c_enable(i2c_base, true);
}
/*
* i2c_flush_rxfifo - Flushes the i2c RX FIFO
*
* Flushes the i2c RX FIFO
*/
static void i2c_flush_rxfifo(struct i2c_regs *i2c_base)
{
while (readl(&i2c_base->ic_status) & IC_STATUS_RFNE)
readl(&i2c_base->ic_cmd_data);
}
/*
* i2c_wait_for_bb - Waits for bus busy
*
* Waits for bus busy
*/
static int i2c_wait_for_bb(struct i2c_regs *i2c_base)
{
unsigned long start_time_bb = get_timer(0);
while ((readl(&i2c_base->ic_status) & IC_STATUS_MA) ||
!(readl(&i2c_base->ic_status) & IC_STATUS_TFE)) {
/* Evaluate timeout */
if (get_timer(start_time_bb) > (unsigned long)(I2C_BYTE_TO_BB))
return 1;
}
return 0;
}
static int i2c_xfer_init(struct i2c_regs *i2c_base, uchar chip, uint addr,
int alen)
{
if (i2c_wait_for_bb(i2c_base))
return 1;
i2c_setaddress(i2c_base, chip);
while (alen) {
alen--;
/* high byte address going out first */
writel((addr >> (alen * 8)) & 0xff,
&i2c_base->ic_cmd_data);
}
return 0;
}
static int i2c_xfer_finish(struct i2c_regs *i2c_base)
{
ulong start_stop_det = get_timer(0);
while (1) {
if ((readl(&i2c_base->ic_raw_intr_stat) & IC_STOP_DET)) {
readl(&i2c_base->ic_clr_stop_det);
break;
} else if (get_timer(start_stop_det) > I2C_STOPDET_TO) {
break;
}
}
if (i2c_wait_for_bb(i2c_base)) {
printf("Timed out waiting for bus\n");
return 1;
}
i2c_flush_rxfifo(i2c_base);
return 0;
}
/*
* i2c_read - Read from i2c memory
* @chip: target i2c address
* @addr: address to read from
* @alen:
* @buffer: buffer for read data
* @len: no of bytes to be read
*
* Read from i2c memory.
*/
static int __dw_i2c_read(struct i2c_regs *i2c_base, u8 dev, uint addr,
int alen, u8 *buffer, int len)
{
unsigned long start_time_rx;
unsigned int active = 0;
#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
/*
* EEPROM chips that implement "address overflow" are ones
* like Catalyst 24WC04/08/16 which has 9/10/11 bits of
* address and the extra bits end up in the "chip address"
* bit slots. This makes a 24WC08 (1Kbyte) chip look like
* four 256 byte chips.
*
* Note that we consider the length of the address field to
* still be one byte because the extra address bits are
* hidden in the chip address.
*/
dev |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
addr &= ~(CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW << (alen * 8));
debug("%s: fix addr_overflow: dev %02x addr %02x\n", __func__, dev,
addr);
#endif
if (i2c_xfer_init(i2c_base, dev, addr, alen))
return 1;
start_time_rx = get_timer(0);
while (len) {
if (!active) {
/*
* Avoid writing to ic_cmd_data multiple times
* in case this loop spins too quickly and the
* ic_status RFNE bit isn't set after the first
* write. Subsequent writes to ic_cmd_data can
* trigger spurious i2c transfer.
*/
if (len == 1)
writel(IC_CMD | IC_STOP, &i2c_base->ic_cmd_data);
else
writel(IC_CMD, &i2c_base->ic_cmd_data);
active = 1;
}
if (readl(&i2c_base->ic_status) & IC_STATUS_RFNE) {
*buffer++ = (uchar)readl(&i2c_base->ic_cmd_data);
len--;
start_time_rx = get_timer(0);
active = 0;
} else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
return 1;
}
}
return i2c_xfer_finish(i2c_base);
}
/*
* i2c_write - Write to i2c memory
* @chip: target i2c address
* @addr: address to read from
* @alen:
* @buffer: buffer for read data
* @len: no of bytes to be read
*
* Write to i2c memory.
*/
static int __dw_i2c_write(struct i2c_regs *i2c_base, u8 dev, uint addr,
int alen, u8 *buffer, int len)
{
int nb = len;
unsigned long start_time_tx;
#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
/*
* EEPROM chips that implement "address overflow" are ones
* like Catalyst 24WC04/08/16 which has 9/10/11 bits of
* address and the extra bits end up in the "chip address"
* bit slots. This makes a 24WC08 (1Kbyte) chip look like
* four 256 byte chips.
*
* Note that we consider the length of the address field to
* still be one byte because the extra address bits are
* hidden in the chip address.
*/
dev |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
addr &= ~(CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW << (alen * 8));
debug("%s: fix addr_overflow: dev %02x addr %02x\n", __func__, dev,
addr);
#endif
if (i2c_xfer_init(i2c_base, dev, addr, alen))
return 1;
start_time_tx = get_timer(0);
while (len) {
if (readl(&i2c_base->ic_status) & IC_STATUS_TFNF) {
if (--len == 0) {
writel(*buffer | IC_STOP,
&i2c_base->ic_cmd_data);
} else {
writel(*buffer, &i2c_base->ic_cmd_data);
}
buffer++;
start_time_tx = get_timer(0);
} else if (get_timer(start_time_tx) > (nb * I2C_BYTE_TO)) {
printf("Timed out. i2c write Failed\n");
return 1;
}
}
return i2c_xfer_finish(i2c_base);
}
/*
* __dw_i2c_init - Init function
* @speed: required i2c speed
* @slaveaddr: slave address for the device
*
* Initialization function.
*/
static void __dw_i2c_init(struct i2c_regs *i2c_base, int speed, int slaveaddr)
{
/* Disable i2c */
dw_i2c_enable(i2c_base, false);
writel((IC_CON_SD | IC_CON_SPD_FS | IC_CON_MM), &i2c_base->ic_con);
writel(IC_RX_TL, &i2c_base->ic_rx_tl);
writel(IC_TX_TL, &i2c_base->ic_tx_tl);
writel(IC_STOP_DET, &i2c_base->ic_intr_mask);
#ifndef CONFIG_DM_I2C
__dw_i2c_set_bus_speed(i2c_base, NULL, speed);
writel(slaveaddr, &i2c_base->ic_sar);
#endif
/* Enable i2c */
dw_i2c_enable(i2c_base, true);
}
#ifndef CONFIG_DM_I2C
/*
* The legacy I2C functions. These need to get removed once
* all users of this driver are converted to DM.
*/
static struct i2c_regs *i2c_get_base(struct i2c_adapter *adap)
{
switch (adap->hwadapnr) {
#if CONFIG_SYS_I2C_BUS_MAX >= 4
case 3:
return (struct i2c_regs *)CONFIG_SYS_I2C_BASE3;
#endif
#if CONFIG_SYS_I2C_BUS_MAX >= 3
case 2:
return (struct i2c_regs *)CONFIG_SYS_I2C_BASE2;
#endif
#if CONFIG_SYS_I2C_BUS_MAX >= 2
case 1:
return (struct i2c_regs *)CONFIG_SYS_I2C_BASE1;
#endif
case 0:
return (struct i2c_regs *)CONFIG_SYS_I2C_BASE;
default:
printf("Wrong I2C-adapter number %d\n", adap->hwadapnr);
}
return NULL;
}
static unsigned int dw_i2c_set_bus_speed(struct i2c_adapter *adap,
unsigned int speed)
{
adap->speed = speed;
return __dw_i2c_set_bus_speed(i2c_get_base(adap), NULL, speed);
}
static void dw_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
{
__dw_i2c_init(i2c_get_base(adap), speed, slaveaddr);
}
static int dw_i2c_read(struct i2c_adapter *adap, u8 dev, uint addr,
int alen, u8 *buffer, int len)
{
return __dw_i2c_read(i2c_get_base(adap), dev, addr, alen, buffer, len);
}
static int dw_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr,
int alen, u8 *buffer, int len)
{
return __dw_i2c_write(i2c_get_base(adap), dev, addr, alen, buffer, len);
}
/* dw_i2c_probe - Probe the i2c chip */
static int dw_i2c_probe(struct i2c_adapter *adap, u8 dev)
{
struct i2c_regs *i2c_base = i2c_get_base(adap);
u32 tmp;
int ret;
/*
* Try to read the first location of the chip.
*/
ret = __dw_i2c_read(i2c_base, dev, 0, 1, (uchar *)&tmp, 1);
if (ret)
dw_i2c_init(adap, adap->speed, adap->slaveaddr);
return ret;
}
U_BOOT_I2C_ADAP_COMPLETE(dw_0, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
dw_i2c_write, dw_i2c_set_bus_speed,
CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE, 0)
#if CONFIG_SYS_I2C_BUS_MAX >= 2
U_BOOT_I2C_ADAP_COMPLETE(dw_1, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
dw_i2c_write, dw_i2c_set_bus_speed,
CONFIG_SYS_I2C_SPEED1, CONFIG_SYS_I2C_SLAVE1, 1)
#endif
#if CONFIG_SYS_I2C_BUS_MAX >= 3
U_BOOT_I2C_ADAP_COMPLETE(dw_2, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
dw_i2c_write, dw_i2c_set_bus_speed,
CONFIG_SYS_I2C_SPEED2, CONFIG_SYS_I2C_SLAVE2, 2)
#endif
#if CONFIG_SYS_I2C_BUS_MAX >= 4
U_BOOT_I2C_ADAP_COMPLETE(dw_3, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
dw_i2c_write, dw_i2c_set_bus_speed,
CONFIG_SYS_I2C_SPEED3, CONFIG_SYS_I2C_SLAVE3, 3)
#endif
#else /* CONFIG_DM_I2C */
/* The DM I2C functions */
static int designware_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
int nmsgs)
{
struct dw_i2c *i2c = dev_get_priv(bus);
int ret;
debug("i2c_xfer: %d messages\n", nmsgs);
for (; nmsgs > 0; nmsgs--, msg++) {
debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
if (msg->flags & I2C_M_RD) {
ret = __dw_i2c_read(i2c->regs, msg->addr, 0, 0,
msg->buf, msg->len);
} else {
ret = __dw_i2c_write(i2c->regs, msg->addr, 0, 0,
msg->buf, msg->len);
}
if (ret) {
debug("i2c_write: error sending\n");
return -EREMOTEIO;
}
}
return 0;
}
static int designware_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
{
struct dw_i2c *i2c = dev_get_priv(bus);
return __dw_i2c_set_bus_speed(i2c->regs, i2c->scl_sda_cfg, speed);
}
static int designware_i2c_probe_chip(struct udevice *bus, uint chip_addr,
uint chip_flags)
{
struct dw_i2c *i2c = dev_get_priv(bus);
struct i2c_regs *i2c_base = i2c->regs;
u32 tmp;
int ret;
/* Try to read the first location of the chip */
ret = __dw_i2c_read(i2c_base, chip_addr, 0, 1, (uchar *)&tmp, 1);
if (ret)
__dw_i2c_init(i2c_base, 0, 0);
return ret;
}
static int designware_i2c_probe(struct udevice *bus)
{
struct dw_i2c *priv = dev_get_priv(bus);
if (device_is_on_pci_bus(bus)) {
#ifdef CONFIG_DM_PCI
/* Save base address from PCI BAR */
priv->regs = (struct i2c_regs *)
dm_pci_map_bar(bus, PCI_BASE_ADDRESS_0, PCI_REGION_MEM);
#ifdef CONFIG_X86
/* Use BayTrail specific timing values */
priv->scl_sda_cfg = &byt_config;
#endif
#endif
} else {
priv->regs = (struct i2c_regs *)dev_get_addr_ptr(bus);
}
__dw_i2c_init(priv->regs, 0, 0);
return 0;
}
static int designware_i2c_bind(struct udevice *dev)
{
static int num_cards;
char name[20];
/* Create a unique device name for PCI type devices */
if (device_is_on_pci_bus(dev)) {
/*
* ToDo:
* Setting req_seq in the driver is probably not recommended.
* But without a DT alias the number is not configured. And
* using this driver is impossible for PCIe I2C devices.
* This can be removed, once a better (correct) way for this
* is found and implemented.
*/
dev->req_seq = num_cards;
sprintf(name, "i2c_designware#%u", num_cards++);
device_set_name(dev, name);
}
return 0;
}
static const struct dm_i2c_ops designware_i2c_ops = {
.xfer = designware_i2c_xfer,
.probe_chip = designware_i2c_probe_chip,
.set_bus_speed = designware_i2c_set_bus_speed,
};
static const struct udevice_id designware_i2c_ids[] = {
{ .compatible = "snps,designware-i2c" },
{ }
};
U_BOOT_DRIVER(i2c_designware) = {
.name = "i2c_designware",
.id = UCLASS_I2C,
.of_match = designware_i2c_ids,
.bind = designware_i2c_bind,
.probe = designware_i2c_probe,
.priv_auto_alloc_size = sizeof(struct dw_i2c),
.ops = &designware_i2c_ops,
};
#ifdef CONFIG_X86
static struct pci_device_id designware_pci_supported[] = {
/* Intel BayTrail has 7 I2C controller located on the PCI bus */
{ PCI_VDEVICE(INTEL, 0x0f41) },
{ PCI_VDEVICE(INTEL, 0x0f42) },
{ PCI_VDEVICE(INTEL, 0x0f43) },
{ PCI_VDEVICE(INTEL, 0x0f44) },
{ PCI_VDEVICE(INTEL, 0x0f45) },
{ PCI_VDEVICE(INTEL, 0x0f46) },
{ PCI_VDEVICE(INTEL, 0x0f47) },
{},
};
U_BOOT_PCI_DEVICE(i2c_designware, designware_pci_supported);
#endif
#endif /* CONFIG_DM_I2C */
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