u-boot/drivers/spi/tegra114_spi.c
Simon Glass 20edd1ac7a tegra: spi: Support slow SPI rates
Use the oscillator as the source clock when we cannot achieve a low-enough
speed with the peripheral clock. This happens when we request 3MHz on a SPI
clock, for example.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
2015-06-09 09:56:13 -07:00

416 lines
12 KiB
C

/*
* NVIDIA Tegra SPI controller (T114 and later)
*
* Copyright (c) 2010-2013 NVIDIA Corporation
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <dm.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#include <asm/arch-tegra/clk_rst.h>
#include <spi.h>
#include <fdtdec.h>
#include "tegra_spi.h"
DECLARE_GLOBAL_DATA_PTR;
/* COMMAND1 */
#define SPI_CMD1_GO (1 << 31)
#define SPI_CMD1_M_S (1 << 30)
#define SPI_CMD1_MODE_MASK 0x3
#define SPI_CMD1_MODE_SHIFT 28
#define SPI_CMD1_CS_SEL_MASK 0x3
#define SPI_CMD1_CS_SEL_SHIFT 26
#define SPI_CMD1_CS_POL_INACTIVE3 (1 << 25)
#define SPI_CMD1_CS_POL_INACTIVE2 (1 << 24)
#define SPI_CMD1_CS_POL_INACTIVE1 (1 << 23)
#define SPI_CMD1_CS_POL_INACTIVE0 (1 << 22)
#define SPI_CMD1_CS_SW_HW (1 << 21)
#define SPI_CMD1_CS_SW_VAL (1 << 20)
#define SPI_CMD1_IDLE_SDA_MASK 0x3
#define SPI_CMD1_IDLE_SDA_SHIFT 18
#define SPI_CMD1_BIDIR (1 << 17)
#define SPI_CMD1_LSBI_FE (1 << 16)
#define SPI_CMD1_LSBY_FE (1 << 15)
#define SPI_CMD1_BOTH_EN_BIT (1 << 14)
#define SPI_CMD1_BOTH_EN_BYTE (1 << 13)
#define SPI_CMD1_RX_EN (1 << 12)
#define SPI_CMD1_TX_EN (1 << 11)
#define SPI_CMD1_PACKED (1 << 5)
#define SPI_CMD1_BIT_LEN_MASK 0x1F
#define SPI_CMD1_BIT_LEN_SHIFT 0
/* COMMAND2 */
#define SPI_CMD2_TX_CLK_TAP_DELAY (1 << 6)
#define SPI_CMD2_TX_CLK_TAP_DELAY_MASK (0x3F << 6)
#define SPI_CMD2_RX_CLK_TAP_DELAY (1 << 0)
#define SPI_CMD2_RX_CLK_TAP_DELAY_MASK (0x3F << 0)
/* TRANSFER STATUS */
#define SPI_XFER_STS_RDY (1 << 30)
/* FIFO STATUS */
#define SPI_FIFO_STS_CS_INACTIVE (1 << 31)
#define SPI_FIFO_STS_FRAME_END (1 << 30)
#define SPI_FIFO_STS_RX_FIFO_FLUSH (1 << 15)
#define SPI_FIFO_STS_TX_FIFO_FLUSH (1 << 14)
#define SPI_FIFO_STS_ERR (1 << 8)
#define SPI_FIFO_STS_TX_FIFO_OVF (1 << 7)
#define SPI_FIFO_STS_TX_FIFO_UNR (1 << 6)
#define SPI_FIFO_STS_RX_FIFO_OVF (1 << 5)
#define SPI_FIFO_STS_RX_FIFO_UNR (1 << 4)
#define SPI_FIFO_STS_TX_FIFO_FULL (1 << 3)
#define SPI_FIFO_STS_TX_FIFO_EMPTY (1 << 2)
#define SPI_FIFO_STS_RX_FIFO_FULL (1 << 1)
#define SPI_FIFO_STS_RX_FIFO_EMPTY (1 << 0)
#define SPI_TIMEOUT 1000
#define TEGRA_SPI_MAX_FREQ 52000000
struct spi_regs {
u32 command1; /* 000:SPI_COMMAND1 register */
u32 command2; /* 004:SPI_COMMAND2 register */
u32 timing1; /* 008:SPI_CS_TIM1 register */
u32 timing2; /* 00c:SPI_CS_TIM2 register */
u32 xfer_status;/* 010:SPI_TRANS_STATUS register */
u32 fifo_status;/* 014:SPI_FIFO_STATUS register */
u32 tx_data; /* 018:SPI_TX_DATA register */
u32 rx_data; /* 01c:SPI_RX_DATA register */
u32 dma_ctl; /* 020:SPI_DMA_CTL register */
u32 dma_blk; /* 024:SPI_DMA_BLK register */
u32 rsvd[56]; /* 028-107 reserved */
u32 tx_fifo; /* 108:SPI_FIFO1 register */
u32 rsvd2[31]; /* 10c-187 reserved */
u32 rx_fifo; /* 188:SPI_FIFO2 register */
u32 spare_ctl; /* 18c:SPI_SPARE_CTRL register */
};
struct tegra114_spi_priv {
struct spi_regs *regs;
unsigned int freq;
unsigned int mode;
int periph_id;
int valid;
int last_transaction_us;
};
static int tegra114_spi_ofdata_to_platdata(struct udevice *bus)
{
struct tegra_spi_platdata *plat = bus->platdata;
const void *blob = gd->fdt_blob;
int node = bus->of_offset;
plat->base = fdtdec_get_addr(blob, node, "reg");
plat->periph_id = clock_decode_periph_id(blob, node);
if (plat->periph_id == PERIPH_ID_NONE) {
debug("%s: could not decode periph 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: base=%#08lx, periph_id=%d, max-frequency=%d, deactivate_delay=%d\n",
__func__, plat->base, plat->periph_id, plat->frequency,
plat->deactivate_delay_us);
return 0;
}
static int tegra114_spi_probe(struct udevice *bus)
{
struct tegra_spi_platdata *plat = dev_get_platdata(bus);
struct tegra114_spi_priv *priv = dev_get_priv(bus);
struct spi_regs *regs;
ulong rate;
priv->regs = (struct spi_regs *)plat->base;
regs = priv->regs;
priv->last_transaction_us = timer_get_us();
priv->freq = plat->frequency;
priv->periph_id = plat->periph_id;
/*
* Change SPI clock to correct frequency, PLLP_OUT0 source, falling
* back to the oscillator if that is too fast.
*/
rate = clock_start_periph_pll(priv->periph_id, CLOCK_ID_PERIPH,
priv->freq);
if (rate > priv->freq + 100000) {
rate = clock_start_periph_pll(priv->periph_id, CLOCK_ID_OSC,
priv->freq);
if (rate != priv->freq) {
printf("Warning: SPI '%s' requested clock %u, actual clock %lu\n",
bus->name, priv->freq, rate);
}
}
/* Clear stale status here */
setbits_le32(&regs->fifo_status,
SPI_FIFO_STS_ERR |
SPI_FIFO_STS_TX_FIFO_OVF |
SPI_FIFO_STS_TX_FIFO_UNR |
SPI_FIFO_STS_RX_FIFO_OVF |
SPI_FIFO_STS_RX_FIFO_UNR |
SPI_FIFO_STS_TX_FIFO_FULL |
SPI_FIFO_STS_TX_FIFO_EMPTY |
SPI_FIFO_STS_RX_FIFO_FULL |
SPI_FIFO_STS_RX_FIFO_EMPTY);
debug("%s: FIFO STATUS = %08x\n", __func__, readl(&regs->fifo_status));
setbits_le32(&priv->regs->command1, SPI_CMD1_M_S | SPI_CMD1_CS_SW_HW |
(priv->mode << SPI_CMD1_MODE_SHIFT) | SPI_CMD1_CS_SW_VAL);
debug("%s: COMMAND1 = %08x\n", __func__, readl(&regs->command1));
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 tegra_spi_platdata *pdata = dev_get_platdata(bus);
struct tegra114_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->command1, SPI_CMD1_CS_SW_VAL);
}
/**
* 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 tegra_spi_platdata *pdata = dev_get_platdata(bus);
struct tegra114_spi_priv *priv = dev_get_priv(bus);
setbits_le32(&priv->regs->command1, SPI_CMD1_CS_SW_VAL);
/* 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 tegra114_spi_xfer(struct udevice *dev, unsigned int bitlen,
const void *data_out, void *data_in,
unsigned long flags)
{
struct udevice *bus = dev->parent;
struct tegra114_spi_priv *priv = dev_get_priv(bus);
struct spi_regs *regs = priv->regs;
u32 reg, tmpdout, tmpdin = 0;
const u8 *dout = data_out;
u8 *din = data_in;
int num_bytes;
int ret;
debug("%s: slave %u:%u dout %p din %p bitlen %u\n",
__func__, bus->seq, spi_chip_select(dev), dout, din, bitlen);
if (bitlen % 8)
return -1;
num_bytes = bitlen / 8;
ret = 0;
if (flags & SPI_XFER_BEGIN)
spi_cs_activate(dev);
/* clear all error status bits */
reg = readl(&regs->fifo_status);
writel(reg, &regs->fifo_status);
clrsetbits_le32(&regs->command1, SPI_CMD1_CS_SW_VAL,
SPI_CMD1_RX_EN | SPI_CMD1_TX_EN | SPI_CMD1_LSBY_FE |
(spi_chip_select(dev) << SPI_CMD1_CS_SEL_SHIFT));
/* set xfer size to 1 block (32 bits) */
writel(0, &regs->dma_blk);
/* handle data in 32-bit chunks */
while (num_bytes > 0) {
int bytes;
int tm, i;
tmpdout = 0;
bytes = (num_bytes > 4) ? 4 : num_bytes;
if (dout != NULL) {
for (i = 0; i < bytes; ++i)
tmpdout = (tmpdout << 8) | dout[i];
dout += bytes;
}
num_bytes -= bytes;
/* clear ready bit */
setbits_le32(&regs->xfer_status, SPI_XFER_STS_RDY);
clrsetbits_le32(&regs->command1,
SPI_CMD1_BIT_LEN_MASK << SPI_CMD1_BIT_LEN_SHIFT,
(bytes * 8 - 1) << SPI_CMD1_BIT_LEN_SHIFT);
writel(tmpdout, &regs->tx_fifo);
setbits_le32(&regs->command1, SPI_CMD1_GO);
/*
* Wait for SPI transmit FIFO to empty, or to time out.
* The RX FIFO status will be read and cleared last
*/
for (tm = 0; tm < SPI_TIMEOUT; ++tm) {
u32 fifo_status, xfer_status;
xfer_status = readl(&regs->xfer_status);
if (!(xfer_status & SPI_XFER_STS_RDY))
continue;
fifo_status = readl(&regs->fifo_status);
if (fifo_status & SPI_FIFO_STS_ERR) {
debug("%s: got a fifo error: ", __func__);
if (fifo_status & SPI_FIFO_STS_TX_FIFO_OVF)
debug("tx FIFO overflow ");
if (fifo_status & SPI_FIFO_STS_TX_FIFO_UNR)
debug("tx FIFO underrun ");
if (fifo_status & SPI_FIFO_STS_RX_FIFO_OVF)
debug("rx FIFO overflow ");
if (fifo_status & SPI_FIFO_STS_RX_FIFO_UNR)
debug("rx FIFO underrun ");
if (fifo_status & SPI_FIFO_STS_TX_FIFO_FULL)
debug("tx FIFO full ");
if (fifo_status & SPI_FIFO_STS_TX_FIFO_EMPTY)
debug("tx FIFO empty ");
if (fifo_status & SPI_FIFO_STS_RX_FIFO_FULL)
debug("rx FIFO full ");
if (fifo_status & SPI_FIFO_STS_RX_FIFO_EMPTY)
debug("rx FIFO empty ");
debug("\n");
break;
}
if (!(fifo_status & SPI_FIFO_STS_RX_FIFO_EMPTY)) {
tmpdin = readl(&regs->rx_fifo);
/* swap bytes read in */
if (din != NULL) {
for (i = bytes - 1; i >= 0; --i) {
din[i] = tmpdin & 0xff;
tmpdin >>= 8;
}
din += bytes;
}
/* We can exit when we've had both RX and TX */
break;
}
}
if (tm >= SPI_TIMEOUT)
ret = tm;
/* clear ACK RDY, etc. bits */
writel(readl(&regs->fifo_status), &regs->fifo_status);
}
if (flags & SPI_XFER_END)
spi_cs_deactivate(dev);
debug("%s: transfer ended. Value=%08x, fifo_status = %08x\n",
__func__, tmpdin, readl(&regs->fifo_status));
if (ret) {
printf("%s: timeout during SPI transfer, tm %d\n",
__func__, ret);
return -1;
}
return ret;
}
static int tegra114_spi_set_speed(struct udevice *bus, uint speed)
{
struct tegra_spi_platdata *plat = bus->platdata;
struct tegra114_spi_priv *priv = dev_get_priv(bus);
if (speed > plat->frequency)
speed = plat->frequency;
priv->freq = speed;
debug("%s: regs=%p, speed=%d\n", __func__, priv->regs, priv->freq);
return 0;
}
static int tegra114_spi_set_mode(struct udevice *bus, uint mode)
{
struct tegra114_spi_priv *priv = dev_get_priv(bus);
priv->mode = mode;
debug("%s: regs=%p, mode=%d\n", __func__, priv->regs, priv->mode);
return 0;
}
static const struct dm_spi_ops tegra114_spi_ops = {
.xfer = tegra114_spi_xfer,
.set_speed = tegra114_spi_set_speed,
.set_mode = tegra114_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 tegra114_spi_ids[] = {
{ .compatible = "nvidia,tegra114-spi" },
{ }
};
U_BOOT_DRIVER(tegra114_spi) = {
.name = "tegra114_spi",
.id = UCLASS_SPI,
.of_match = tegra114_spi_ids,
.ops = &tegra114_spi_ops,
.ofdata_to_platdata = tegra114_spi_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct tegra_spi_platdata),
.priv_auto_alloc_size = sizeof(struct tegra114_spi_priv),
.probe = tegra114_spi_probe,
};