- 根目录:
- drivers
- spi
- spi-xlp.c
/*
* Copyright (C) 2003-2015 Broadcom Corporation
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 (GPL v2)
* as published by the Free Software Foundation.
*
* 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.
*/
#include <linux/clk.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/of.h>
#include <linux/interrupt.h>
/* SPI Configuration Register */
#define XLP_SPI_CONFIG 0x00
#define XLP_SPI_CPHA BIT(0)
#define XLP_SPI_CPOL BIT(1)
#define XLP_SPI_CS_POL BIT(2)
#define XLP_SPI_TXMISO_EN BIT(3)
#define XLP_SPI_TXMOSI_EN BIT(4)
#define XLP_SPI_RXMISO_EN BIT(5)
#define XLP_SPI_CS_LSBFE BIT(10)
#define XLP_SPI_RXCAP_EN BIT(11)
/* SPI Frequency Divider Register */
#define XLP_SPI_FDIV 0x04
/* SPI Command Register */
#define XLP_SPI_CMD 0x08
#define XLP_SPI_CMD_IDLE_MASK 0x0
#define XLP_SPI_CMD_TX_MASK 0x1
#define XLP_SPI_CMD_RX_MASK 0x2
#define XLP_SPI_CMD_TXRX_MASK 0x3
#define XLP_SPI_CMD_CONT BIT(4)
#define XLP_SPI_XFR_BITCNT_SHIFT 16
/* SPI Status Register */
#define XLP_SPI_STATUS 0x0c
#define XLP_SPI_XFR_PENDING BIT(0)
#define XLP_SPI_XFR_DONE BIT(1)
#define XLP_SPI_TX_INT BIT(2)
#define XLP_SPI_RX_INT BIT(3)
#define XLP_SPI_TX_UF BIT(4)
#define XLP_SPI_RX_OF BIT(5)
#define XLP_SPI_STAT_MASK 0x3f
/* SPI Interrupt Enable Register */
#define XLP_SPI_INTR_EN 0x10
#define XLP_SPI_INTR_DONE BIT(0)
#define XLP_SPI_INTR_TXTH BIT(1)
#define XLP_SPI_INTR_RXTH BIT(2)
#define XLP_SPI_INTR_TXUF BIT(3)
#define XLP_SPI_INTR_RXOF BIT(4)
/* SPI FIFO Threshold Register */
#define XLP_SPI_FIFO_THRESH 0x14
/* SPI FIFO Word Count Register */
#define XLP_SPI_FIFO_WCNT 0x18
#define XLP_SPI_RXFIFO_WCNT_MASK 0xf
#define XLP_SPI_TXFIFO_WCNT_MASK 0xf0
#define XLP_SPI_TXFIFO_WCNT_SHIFT 4
/* SPI Transmit Data FIFO Register */
#define XLP_SPI_TXDATA_FIFO 0x1c
/* SPI Receive Data FIFO Register */
#define XLP_SPI_RXDATA_FIFO 0x20
/* SPI System Control Register */
#define XLP_SPI_SYSCTRL 0x100
#define XLP_SPI_SYS_RESET BIT(0)
#define XLP_SPI_SYS_CLKDIS BIT(1)
#define XLP_SPI_SYS_PMEN BIT(8)
#define SPI_CS_OFFSET 0x40
#define XLP_SPI_TXRXTH 0x80
#define XLP_SPI_FIFO_SIZE 8
#define XLP_SPI_MAX_CS 4
#define XLP_SPI_DEFAULT_FREQ 133333333
#define XLP_SPI_FDIV_MIN 4
#define XLP_SPI_FDIV_MAX 65535
/*
* SPI can transfer only 28 bytes properly at a time. So split the
* transfer into 28 bytes size.
*/
#define XLP_SPI_XFER_SIZE 28
struct xlp_spi_priv {
struct device dev; /* device structure */
void __iomem *base; /* spi registers base address */
const u8 *tx_buf; /* tx data buffer */
u8 *rx_buf; /* rx data buffer */
int tx_len; /* tx xfer length */
int rx_len; /* rx xfer length */
int txerrors; /* TXFIFO underflow count */
int rxerrors; /* RXFIFO overflow count */
int cs; /* slave device chip select */
u32 spi_clk; /* spi clock frequency */
bool cmd_cont; /* cs active */
struct completion done; /* completion notification */
};
static inline u32 xlp_spi_reg_read(struct xlp_spi_priv *priv,
int cs, int regoff)
{
return readl(priv->base + regoff + cs * SPI_CS_OFFSET);
}
static inline void xlp_spi_reg_write(struct xlp_spi_priv *priv, int cs,
int regoff, u32 val)
{
writel(val, priv->base + regoff + cs * SPI_CS_OFFSET);
}
static inline void xlp_spi_sysctl_write(struct xlp_spi_priv *priv,
int regoff, u32 val)
{
writel(val, priv->base + regoff);
}
/*
* Setup global SPI_SYSCTRL register for all SPI channels.
*/
static void xlp_spi_sysctl_setup(struct xlp_spi_priv *xspi)
{
int cs;
for (cs = 0; cs < XLP_SPI_MAX_CS; cs++)
xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL,
XLP_SPI_SYS_RESET << cs);
xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL, XLP_SPI_SYS_PMEN);
}
static int xlp_spi_setup(struct spi_device *spi)
{
struct xlp_spi_priv *xspi;
u32 fdiv, cfg;
int cs;
xspi = spi_master_get_devdata(spi->master);
cs = spi->chip_select;
/*
* The value of fdiv must be between 4 and 65535.
*/
fdiv = DIV_ROUND_UP(xspi->spi_clk, spi->max_speed_hz);
if (fdiv > XLP_SPI_FDIV_MAX)
fdiv = XLP_SPI_FDIV_MAX;
else if (fdiv < XLP_SPI_FDIV_MIN)
fdiv = XLP_SPI_FDIV_MIN;
xlp_spi_reg_write(xspi, cs, XLP_SPI_FDIV, fdiv);
xlp_spi_reg_write(xspi, cs, XLP_SPI_FIFO_THRESH, XLP_SPI_TXRXTH);
cfg = xlp_spi_reg_read(xspi, cs, XLP_SPI_CONFIG);
if (spi->mode & SPI_CPHA)
cfg |= XLP_SPI_CPHA;
else
cfg &= ~XLP_SPI_CPHA;
if (spi->mode & SPI_CPOL)
cfg |= XLP_SPI_CPOL;
else
cfg &= ~XLP_SPI_CPOL;
if (!(spi->mode & SPI_CS_HIGH))
cfg |= XLP_SPI_CS_POL;
else
cfg &= ~XLP_SPI_CS_POL;
if (spi->mode & SPI_LSB_FIRST)
cfg |= XLP_SPI_CS_LSBFE;
else
cfg &= ~XLP_SPI_CS_LSBFE;
cfg |= XLP_SPI_TXMOSI_EN | XLP_SPI_RXMISO_EN;
if (fdiv == 4)
cfg |= XLP_SPI_RXCAP_EN;
xlp_spi_reg_write(xspi, cs, XLP_SPI_CONFIG, cfg);
return 0;
}
static void xlp_spi_read_rxfifo(struct xlp_spi_priv *xspi)
{
u32 rx_data, rxfifo_cnt;
int i, j, nbytes;
rxfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
rxfifo_cnt &= XLP_SPI_RXFIFO_WCNT_MASK;
while (rxfifo_cnt) {
rx_data = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_RXDATA_FIFO);
j = 0;
nbytes = min(xspi->rx_len, 4);
for (i = nbytes - 1; i >= 0; i--, j++)
xspi->rx_buf[i] = (rx_data >> (j * 8)) & 0xff;
xspi->rx_len -= nbytes;
xspi->rx_buf += nbytes;
rxfifo_cnt--;
}
}
static void xlp_spi_fill_txfifo(struct xlp_spi_priv *xspi)
{
u32 tx_data, txfifo_cnt;
int i, j, nbytes;
txfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
txfifo_cnt &= XLP_SPI_TXFIFO_WCNT_MASK;
txfifo_cnt >>= XLP_SPI_TXFIFO_WCNT_SHIFT;
while (xspi->tx_len && (txfifo_cnt < XLP_SPI_FIFO_SIZE)) {
j = 0;
tx_data = 0;
nbytes = min(xspi->tx_len, 4);
for (i = nbytes - 1; i >= 0; i--, j++)
tx_data |= xspi->tx_buf[i] << (j * 8);
xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_TXDATA_FIFO, tx_data);
xspi->tx_len -= nbytes;
xspi->tx_buf += nbytes;
txfifo_cnt++;
}
}
static irqreturn_t xlp_spi_interrupt(int irq, void *dev_id)
{
struct xlp_spi_priv *xspi = dev_id;
u32 stat;
stat = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_STATUS) &
XLP_SPI_STAT_MASK;
if (!stat)
return IRQ_NONE;
if (stat & XLP_SPI_TX_INT) {
if (xspi->tx_len)
xlp_spi_fill_txfifo(xspi);
if (stat & XLP_SPI_TX_UF)
xspi->txerrors++;
}
if (stat & XLP_SPI_RX_INT) {
if (xspi->rx_len)
xlp_spi_read_rxfifo(xspi);
if (stat & XLP_SPI_RX_OF)
xspi->rxerrors++;
}
/* write status back to clear interrupts */
xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_STATUS, stat);
if (stat & XLP_SPI_XFR_DONE)
complete(&xspi->done);
return IRQ_HANDLED;
}
static void xlp_spi_send_cmd(struct xlp_spi_priv *xspi, int xfer_len,
int cmd_cont)
{
u32 cmd = 0;
if (xspi->tx_buf)
cmd |= XLP_SPI_CMD_TX_MASK;
if (xspi->rx_buf)
cmd |= XLP_SPI_CMD_RX_MASK;
if (cmd_cont)
cmd |= XLP_SPI_CMD_CONT;
cmd |= ((xfer_len * 8 - 1) << XLP_SPI_XFR_BITCNT_SHIFT);
xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_CMD, cmd);
}
static int xlp_spi_xfer_block(struct xlp_spi_priv *xs,
const unsigned char *tx_buf,
unsigned char *rx_buf, int xfer_len, int cmd_cont)
{
int timeout;
u32 intr_mask = 0;
xs->tx_buf = tx_buf;
xs->rx_buf = rx_buf;
xs->tx_len = (xs->tx_buf == NULL) ? 0 : xfer_len;
xs->rx_len = (xs->rx_buf == NULL) ? 0 : xfer_len;
xs->txerrors = xs->rxerrors = 0;
/* fill TXDATA_FIFO, then send the CMD */
if (xs->tx_len)
xlp_spi_fill_txfifo(xs);
xlp_spi_send_cmd(xs, xfer_len, cmd_cont);
/*
* We are getting some spurious tx interrupts, so avoid enabling
* tx interrupts when only rx is in process.
* Enable all the interrupts in tx case.
*/
if (xs->tx_len)
intr_mask |= XLP_SPI_INTR_TXTH | XLP_SPI_INTR_TXUF |
XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;
else
intr_mask |= XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;
intr_mask |= XLP_SPI_INTR_DONE;
xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, intr_mask);
timeout = wait_for_completion_timeout(&xs->done,
msecs_to_jiffies(1000));
/* Disable interrupts */
xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, 0x0);
if (!timeout) {
dev_err(&xs->dev, "xfer timedout!\n");
goto out;
}
if (xs->txerrors || xs->rxerrors)
dev_err(&xs->dev, "Over/Underflow rx %d tx %d xfer %d!\n",
xs->rxerrors, xs->txerrors, xfer_len);
return xfer_len;
out:
return -ETIMEDOUT;
}
static int xlp_spi_txrx_bufs(struct xlp_spi_priv *xs, struct spi_transfer *t)
{
int bytesleft, sz;
unsigned char *rx_buf;
const unsigned char *tx_buf;
tx_buf = t->tx_buf;
rx_buf = t->rx_buf;
bytesleft = t->len;
while (bytesleft) {
if (bytesleft > XLP_SPI_XFER_SIZE)
sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
XLP_SPI_XFER_SIZE, 1);
else
sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
bytesleft, xs->cmd_cont);
if (sz < 0)
return sz;
bytesleft -= sz;
if (tx_buf)
tx_buf += sz;
if (rx_buf)
rx_buf += sz;
}
return bytesleft;
}
static int xlp_spi_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *t)
{
struct xlp_spi_priv *xspi = spi_master_get_devdata(master);
int ret = 0;
xspi->cs = spi->chip_select;
xspi->dev = spi->dev;
if (spi_transfer_is_last(master, t))
xspi->cmd_cont = 0;
else
xspi->cmd_cont = 1;
if (xlp_spi_txrx_bufs(xspi, t))
ret = -EIO;
spi_finalize_current_transfer(master);
return ret;
}
static int xlp_spi_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct xlp_spi_priv *xspi;
struct resource *res;
struct clk *clk;
int irq, err;
xspi = devm_kzalloc(&pdev->dev, sizeof(*xspi), GFP_KERNEL);
if (!xspi)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
xspi->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(xspi->base))
return PTR_ERR(xspi->base);
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "no IRQ resource found\n");
return -EINVAL;
}
err = devm_request_irq(&pdev->dev, irq, xlp_spi_interrupt, 0,
pdev->name, xspi);
if (err) {
dev_err(&pdev->dev, "unable to request irq %d\n", irq);
return err;
}
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "could not get spi clock\n");
return -ENODEV;
}
xspi->spi_clk = clk_get_rate(clk);
master = spi_alloc_master(&pdev->dev, 0);
if (!master) {
dev_err(&pdev->dev, "could not alloc master\n");
return -ENOMEM;
}
master->bus_num = 0;
master->num_chipselect = XLP_SPI_MAX_CS;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
master->setup = xlp_spi_setup;
master->transfer_one = xlp_spi_transfer_one;
master->dev.of_node = pdev->dev.of_node;
init_completion(&xspi->done);
spi_master_set_devdata(master, xspi);
xlp_spi_sysctl_setup(xspi);
/* register spi controller */
err = devm_spi_register_master(&pdev->dev, master);
if (err) {
dev_err(&pdev->dev, "spi register master failed!\n");
spi_master_put(master);
return err;
}
return 0;
}
static const struct of_device_id xlp_spi_dt_id[] = {
{ .compatible = "netlogic,xlp832-spi" },
{ },
};
static struct platform_driver xlp_spi_driver = {
.probe = xlp_spi_probe,
.driver = {
.name = "xlp-spi",
.of_match_table = xlp_spi_dt_id,
},
};
module_platform_driver(xlp_spi_driver);
MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
MODULE_DESCRIPTION("Netlogic XLP SPI controller driver");
MODULE_LICENSE("GPL v2");