u-boot/drivers/spi/exynos_spi.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

430 lines
11 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2012 SAMSUNG Electronics
* Padmavathi Venna <padma.v@samsung.com>
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <malloc.h>
#include <spi.h>
#include <fdtdec.h>
#include <asm/arch/clk.h>
#include <asm/arch/clock.h>
#include <asm/arch/cpu.h>
#include <asm/arch/gpio.h>
#include <asm/arch/pinmux.h>
#include <asm/arch/spi.h>
#include <asm/io.h>
DECLARE_GLOBAL_DATA_PTR;
struct exynos_spi_platdata {
enum periph_id periph_id;
s32 frequency; /* Default clock frequency, -1 for none */
struct exynos_spi *regs;
uint deactivate_delay_us; /* Delay to wait after deactivate */
};
struct exynos_spi_priv {
struct exynos_spi *regs;
unsigned int freq; /* Default frequency */
unsigned int mode;
enum periph_id periph_id; /* Peripheral ID for this device */
unsigned int fifo_size;
int skip_preamble;
ulong last_transaction_us; /* Time of last transaction end */
};
/**
* Flush spi tx, rx fifos and reset the SPI controller
*
* @param regs Pointer to SPI registers
*/
static void spi_flush_fifo(struct exynos_spi *regs)
{
clrsetbits_le32(&regs->ch_cfg, SPI_CH_HS_EN, SPI_CH_RST);
clrbits_le32(&regs->ch_cfg, SPI_CH_RST);
setbits_le32(&regs->ch_cfg, SPI_TX_CH_ON | SPI_RX_CH_ON);
}
static void spi_get_fifo_levels(struct exynos_spi *regs,
int *rx_lvl, int *tx_lvl)
{
uint32_t spi_sts = readl(&regs->spi_sts);
*rx_lvl = (spi_sts >> SPI_RX_LVL_OFFSET) & SPI_FIFO_LVL_MASK;
*tx_lvl = (spi_sts >> SPI_TX_LVL_OFFSET) & SPI_FIFO_LVL_MASK;
}
/**
* If there's something to transfer, do a software reset and set a
* transaction size.
*
* @param regs SPI peripheral registers
* @param count Number of bytes to transfer
* @param step Number of bytes to transfer in each packet (1 or 4)
*/
static void spi_request_bytes(struct exynos_spi *regs, int count, int step)
{
debug("%s: regs=%p, count=%d, step=%d\n", __func__, regs, count, step);
/* For word address we need to swap bytes */
if (step == 4) {
setbits_le32(&regs->mode_cfg,
SPI_MODE_CH_WIDTH_WORD | SPI_MODE_BUS_WIDTH_WORD);
count /= 4;
setbits_le32(&regs->swap_cfg, SPI_TX_SWAP_EN | SPI_RX_SWAP_EN |
SPI_TX_BYTE_SWAP | SPI_RX_BYTE_SWAP |
SPI_TX_HWORD_SWAP | SPI_RX_HWORD_SWAP);
} else {
/* Select byte access and clear the swap configuration */
clrbits_le32(&regs->mode_cfg,
SPI_MODE_CH_WIDTH_WORD | SPI_MODE_BUS_WIDTH_WORD);
writel(0, &regs->swap_cfg);
}
assert(count && count < (1 << 16));
setbits_le32(&regs->ch_cfg, SPI_CH_RST);
clrbits_le32(&regs->ch_cfg, SPI_CH_RST);
writel(count | SPI_PACKET_CNT_EN, &regs->pkt_cnt);
}
static int spi_rx_tx(struct exynos_spi_priv *priv, int todo,
void **dinp, void const **doutp, unsigned long flags)
{
struct exynos_spi *regs = priv->regs;
uchar *rxp = *dinp;
const uchar *txp = *doutp;
int rx_lvl, tx_lvl;
uint out_bytes, in_bytes;
int toread;
unsigned start = get_timer(0);
int stopping;
int step;
out_bytes = in_bytes = todo;
stopping = priv->skip_preamble && (flags & SPI_XFER_END) &&
!(priv->mode & SPI_SLAVE);
/*
* Try to transfer words if we can. This helps read performance at
* SPI clock speeds above about 20MHz.
*/
step = 1;
if (!((todo | (uintptr_t)rxp | (uintptr_t)txp) & 3) &&
!priv->skip_preamble)
step = 4;
/*
* If there's something to send, do a software reset and set a
* transaction size.
*/
spi_request_bytes(regs, todo, step);
/*
* Bytes are transmitted/received in pairs. Wait to receive all the
* data because then transmission will be done as well.
*/
toread = in_bytes;
while (in_bytes) {
int temp;
/* Keep the fifos full/empty. */
spi_get_fifo_levels(regs, &rx_lvl, &tx_lvl);
/*
* Don't completely fill the txfifo, since we don't want our
* rxfifo to overflow, and it may already contain data.
*/
while (tx_lvl < priv->fifo_size/2 && out_bytes) {
if (!txp)
temp = -1;
else if (step == 4)
temp = *(uint32_t *)txp;
else
temp = *txp;
writel(temp, &regs->tx_data);
out_bytes -= step;
if (txp)
txp += step;
tx_lvl += step;
}
if (rx_lvl >= step) {
while (rx_lvl >= step) {
temp = readl(&regs->rx_data);
if (priv->skip_preamble) {
if (temp == SPI_PREAMBLE_END_BYTE) {
priv->skip_preamble = 0;
stopping = 0;
}
} else {
if (rxp || stopping) {
if (step == 4)
*(uint32_t *)rxp = temp;
else
*rxp = temp;
rxp += step;
}
in_bytes -= step;
}
toread -= step;
rx_lvl -= step;
}
} else if (!toread) {
/*
* We have run out of input data, but haven't read
* enough bytes after the preamble yet. Read some more,
* and make sure that we transmit dummy bytes too, to
* keep things going.
*/
assert(!out_bytes);
out_bytes = in_bytes;
toread = in_bytes;
txp = NULL;
spi_request_bytes(regs, toread, step);
}
if (priv->skip_preamble && get_timer(start) > 100) {
debug("SPI timeout: in_bytes=%d, out_bytes=%d, ",
in_bytes, out_bytes);
return -ETIMEDOUT;
}
}
*dinp = rxp;
*doutp = txp;
return 0;
}
/**
* Activate the CS by driving it LOW
*
* @param slave Pointer to spi_slave to which controller has to
* communicate with
*/
static void spi_cs_activate(struct udevice *dev)
{
struct udevice *bus = dev->parent;
struct exynos_spi_platdata *pdata = dev_get_platdata(bus);
struct exynos_spi_priv *priv = dev_get_priv(bus);
/* If it's too soon to do another transaction, wait */
if (pdata->deactivate_delay_us &&
priv->last_transaction_us) {
ulong delay_us; /* The delay completed so far */
delay_us = timer_get_us() - priv->last_transaction_us;
if (delay_us < pdata->deactivate_delay_us)
udelay(pdata->deactivate_delay_us - delay_us);
}
clrbits_le32(&priv->regs->cs_reg, SPI_SLAVE_SIG_INACT);
debug("Activate CS, bus '%s'\n", bus->name);
priv->skip_preamble = priv->mode & SPI_PREAMBLE;
}
/**
* Deactivate the CS by driving it HIGH
*
* @param slave Pointer to spi_slave to which controller has to
* communicate with
*/
static void spi_cs_deactivate(struct udevice *dev)
{
struct udevice *bus = dev->parent;
struct exynos_spi_platdata *pdata = dev_get_platdata(bus);
struct exynos_spi_priv *priv = dev_get_priv(bus);
setbits_le32(&priv->regs->cs_reg, SPI_SLAVE_SIG_INACT);
/* Remember time of this transaction so we can honour the bus delay */
if (pdata->deactivate_delay_us)
priv->last_transaction_us = timer_get_us();
debug("Deactivate CS, bus '%s'\n", bus->name);
}
static int exynos_spi_ofdata_to_platdata(struct udevice *bus)
{
struct exynos_spi_platdata *plat = bus->platdata;
const void *blob = gd->fdt_blob;
int node = dev_of_offset(bus);
plat->regs = (struct exynos_spi *)devfdt_get_addr(bus);
plat->periph_id = pinmux_decode_periph_id(blob, node);
if (plat->periph_id == PERIPH_ID_NONE) {
debug("%s: Invalid peripheral ID %d\n", __func__,
plat->periph_id);
return -FDT_ERR_NOTFOUND;
}
/* Use 500KHz as a suitable default */
plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency",
500000);
plat->deactivate_delay_us = fdtdec_get_int(blob, node,
"spi-deactivate-delay", 0);
debug("%s: regs=%p, periph_id=%d, max-frequency=%d, deactivate_delay=%d\n",
__func__, plat->regs, plat->periph_id, plat->frequency,
plat->deactivate_delay_us);
return 0;
}
static int exynos_spi_probe(struct udevice *bus)
{
struct exynos_spi_platdata *plat = dev_get_platdata(bus);
struct exynos_spi_priv *priv = dev_get_priv(bus);
priv->regs = plat->regs;
if (plat->periph_id == PERIPH_ID_SPI1 ||
plat->periph_id == PERIPH_ID_SPI2)
priv->fifo_size = 64;
else
priv->fifo_size = 256;
priv->skip_preamble = 0;
priv->last_transaction_us = timer_get_us();
priv->freq = plat->frequency;
priv->periph_id = plat->periph_id;
return 0;
}
static int exynos_spi_claim_bus(struct udevice *dev)
{
struct udevice *bus = dev->parent;
struct exynos_spi_priv *priv = dev_get_priv(bus);
exynos_pinmux_config(priv->periph_id, PINMUX_FLAG_NONE);
spi_flush_fifo(priv->regs);
writel(SPI_FB_DELAY_180, &priv->regs->fb_clk);
return 0;
}
static int exynos_spi_release_bus(struct udevice *dev)
{
struct udevice *bus = dev->parent;
struct exynos_spi_priv *priv = dev_get_priv(bus);
spi_flush_fifo(priv->regs);
return 0;
}
static int exynos_spi_xfer(struct udevice *dev, unsigned int bitlen,
const void *dout, void *din, unsigned long flags)
{
struct udevice *bus = dev->parent;
struct exynos_spi_priv *priv = dev_get_priv(bus);
int upto, todo;
int bytelen;
int ret = 0;
/* spi core configured to do 8 bit transfers */
if (bitlen % 8) {
debug("Non byte aligned SPI transfer.\n");
return -1;
}
/* Start the transaction, if necessary. */
if ((flags & SPI_XFER_BEGIN))
spi_cs_activate(dev);
/*
* Exynos SPI limits each transfer to 65535 transfers. To keep
* things simple, allow a maximum of 65532 bytes. We could allow
* more in word mode, but the performance difference is small.
*/
bytelen = bitlen / 8;
for (upto = 0; !ret && upto < bytelen; upto += todo) {
todo = min(bytelen - upto, (1 << 16) - 4);
ret = spi_rx_tx(priv, todo, &din, &dout, flags);
if (ret)
break;
}
/* Stop the transaction, if necessary. */
if ((flags & SPI_XFER_END) && !(priv->mode & SPI_SLAVE)) {
spi_cs_deactivate(dev);
if (priv->skip_preamble) {
assert(!priv->skip_preamble);
debug("Failed to complete premable transaction\n");
ret = -1;
}
}
return ret;
}
static int exynos_spi_set_speed(struct udevice *bus, uint speed)
{
struct exynos_spi_platdata *plat = bus->platdata;
struct exynos_spi_priv *priv = dev_get_priv(bus);
int ret;
if (speed > plat->frequency)
speed = plat->frequency;
ret = set_spi_clk(priv->periph_id, speed);
if (ret)
return ret;
priv->freq = speed;
debug("%s: regs=%p, speed=%d\n", __func__, priv->regs, priv->freq);
return 0;
}
static int exynos_spi_set_mode(struct udevice *bus, uint mode)
{
struct exynos_spi_priv *priv = dev_get_priv(bus);
uint32_t reg;
reg = readl(&priv->regs->ch_cfg);
reg &= ~(SPI_CH_CPHA_B | SPI_CH_CPOL_L);
if (mode & SPI_CPHA)
reg |= SPI_CH_CPHA_B;
if (mode & SPI_CPOL)
reg |= SPI_CH_CPOL_L;
writel(reg, &priv->regs->ch_cfg);
priv->mode = mode;
debug("%s: regs=%p, mode=%d\n", __func__, priv->regs, priv->mode);
return 0;
}
static const struct dm_spi_ops exynos_spi_ops = {
.claim_bus = exynos_spi_claim_bus,
.release_bus = exynos_spi_release_bus,
.xfer = exynos_spi_xfer,
.set_speed = exynos_spi_set_speed,
.set_mode = exynos_spi_set_mode,
/*
* cs_info is not needed, since we require all chip selects to be
* in the device tree explicitly
*/
};
static const struct udevice_id exynos_spi_ids[] = {
{ .compatible = "samsung,exynos-spi" },
{ }
};
U_BOOT_DRIVER(exynos_spi) = {
.name = "exynos_spi",
.id = UCLASS_SPI,
.of_match = exynos_spi_ids,
.ops = &exynos_spi_ops,
.ofdata_to_platdata = exynos_spi_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct exynos_spi_platdata),
.priv_auto_alloc_size = sizeof(struct exynos_spi_priv),
.probe = exynos_spi_probe,
};