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serial: xuartps: Adds RXBS register support for zynqmp
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This patch adds RXBS register access support for zynqmp.
To avoid the corner error conditions it will consider only
RXBS[2:0] bits while checking the error conditions
(Parity,Framing and BRAK).

Signed-off-by: Nava kishore Manne <navam@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Nava kishore Manne authored and Greg Kroah-Hartman committed Sep 22, 2016
1 parent 54f19b4 commit 3816b2f
Showing 1 changed file with 81 additions and 20 deletions.
101 changes: 81 additions & 20 deletions drivers/tty/serial/xilinx_uartps.c
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Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
#define CDNS_UART_IMR 0x10 /* Interrupt Mask */
#define CDNS_UART_ISR 0x14 /* Interrupt Status */
#define CDNS_UART_BAUDGEN 0x18 /* Baud Rate Generator */
#define CDNS_UART_RXTOUT 0x1C /* RX Timeout */
#define CDNS_UART_RXTOUT 0x1C /* RX Timeout */
#define CDNS_UART_RXWM 0x20 /* RX FIFO Trigger Level */
#define CDNS_UART_MODEMCR 0x24 /* Modem Control */
#define CDNS_UART_MODEMSR 0x28 /* Modem Status */
Expand All @@ -68,6 +68,7 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
#define CDNS_UART_IRRX_PWIDTH 0x3C /* IR Min Received Pulse Width */
#define CDNS_UART_IRTX_PWIDTH 0x40 /* IR Transmitted pulse Width */
#define CDNS_UART_TXWM 0x44 /* TX FIFO Trigger Level */
#define CDNS_UART_RXBS 0x48 /* RX FIFO byte status register */

/* Control Register Bit Definitions */
#define CDNS_UART_CR_STOPBRK 0x00000100 /* Stop TX break */
Expand All @@ -79,6 +80,9 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
#define CDNS_UART_CR_TXRST 0x00000002 /* TX logic reset */
#define CDNS_UART_CR_RXRST 0x00000001 /* RX logic reset */
#define CDNS_UART_CR_RST_TO 0x00000040 /* Restart Timeout Counter */
#define CDNS_UART_RXBS_PARITY 0x00000001 /* Parity error status */
#define CDNS_UART_RXBS_FRAMING 0x00000002 /* Framing error status */
#define CDNS_UART_RXBS_BRK 0x00000004 /* Overrun error status */

/*
* Mode Register:
Expand Down Expand Up @@ -131,8 +135,9 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
CDNS_UART_IXR_TOUT)

/* Goes in read_status_mask for break detection as the HW doesn't do it*/
#define CDNS_UART_IXR_BRK 0x80000000
#define CDNS_UART_IXR_BRK 0x00002000

#define CDNS_UART_RXBS_SUPPORT BIT(1)
/*
* Modem Control register:
* The read/write Modem Control register controls the interface with the modem
Expand Down Expand Up @@ -172,18 +177,29 @@ struct cdns_uart {
struct clk *pclk;
unsigned int baud;
struct notifier_block clk_rate_change_nb;
u32 quirks;
};
struct cdns_platform_data {
u32 quirks;
};
#define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
clk_rate_change_nb);

static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus)
{
struct cdns_uart *cdns_uart = port->private_data;
bool is_rxbs_support;
unsigned int rxbs_status = 0;
unsigned int status_mask;

is_rxbs_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT;

/*
* There is no hardware break detection, so we interpret framing
* error with all-zeros data as a break sequence. Most of the time,
* there's another non-zero byte at the end of the sequence.
*/
if (isrstatus & CDNS_UART_IXR_FRAMING) {
if (!is_rxbs_support && (isrstatus & CDNS_UART_IXR_FRAMING)) {
while (!(readl(port->membase + CDNS_UART_SR) &
CDNS_UART_SR_RXEMPTY)) {
if (!readl(port->membase + CDNS_UART_FIFO)) {
Expand All @@ -200,6 +216,8 @@ static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus)

isrstatus &= port->read_status_mask;
isrstatus &= ~port->ignore_status_mask;
status_mask = port->read_status_mask;
status_mask &= ~port->ignore_status_mask;

if (!(isrstatus & (CDNS_UART_IXR_TOUT | CDNS_UART_IXR_RXTRIG)))
return;
Expand All @@ -208,6 +226,9 @@ static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus)
u32 data;
char status = TTY_NORMAL;

if (is_rxbs_support)
rxbs_status = readl(port->membase + CDNS_UART_RXBS);

data = readl(port->membase + CDNS_UART_FIFO);

/* Non-NULL byte after BREAK is garbage (99%) */
Expand All @@ -217,21 +238,41 @@ static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus)
if (uart_handle_break(port))
continue;
}
if (is_rxbs_support && (rxbs_status & CDNS_UART_RXBS_BRK)) {
port->icount.brk++;
status = TTY_BREAK;
if (uart_handle_break(port))
continue;
}

if (uart_handle_sysrq_char(port, data))
continue;

port->icount.rx++;

if (isrstatus & CDNS_UART_IXR_PARITY) {
port->icount.parity++;
status = TTY_PARITY;
} else if (isrstatus & CDNS_UART_IXR_FRAMING) {
port->icount.frame++;
status = TTY_FRAME;
} else if (isrstatus & CDNS_UART_IXR_OVERRUN) {
port->icount.overrun++;
if (is_rxbs_support) {
if ((rxbs_status & CDNS_UART_RXBS_PARITY)
&& (status_mask & CDNS_UART_IXR_PARITY)) {
port->icount.parity++;
status = TTY_PARITY;
}
if ((rxbs_status & CDNS_UART_RXBS_FRAMING)
&& (status_mask & CDNS_UART_IXR_PARITY)) {
port->icount.frame++;
status = TTY_FRAME;
}
} else {
if (isrstatus & CDNS_UART_IXR_PARITY) {
port->icount.parity++;
status = TTY_PARITY;
}
if (isrstatus & CDNS_UART_IXR_FRAMING) {
port->icount.frame++;
status = TTY_FRAME;
}
}
if (isrstatus & CDNS_UART_IXR_OVERRUN)
port->icount.overrun++;

uart_insert_char(port, isrstatus, CDNS_UART_IXR_OVERRUN,
data, status);
Expand Down Expand Up @@ -736,10 +777,14 @@ static void cdns_uart_set_termios(struct uart_port *port,
*/
static int cdns_uart_startup(struct uart_port *port)
{
struct cdns_uart *cdns_uart = port->private_data;
bool is_brk_support;
int ret;
unsigned long flags;
unsigned int status = 0;

is_brk_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT;

spin_lock_irqsave(&port->lock, flags);

/* Disable the TX and RX */
Expand Down Expand Up @@ -794,7 +839,11 @@ static int cdns_uart_startup(struct uart_port *port)
}

/* Set the Interrupt Registers with desired interrupts */
writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER);
if (is_brk_support)
writel(CDNS_UART_RX_IRQS | CDNS_UART_IXR_BRK,
port->membase + CDNS_UART_IER);
else
writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER);

return 0;
}
Expand Down Expand Up @@ -1328,6 +1377,18 @@ static int cdns_uart_resume(struct device *device)
static SIMPLE_DEV_PM_OPS(cdns_uart_dev_pm_ops, cdns_uart_suspend,
cdns_uart_resume);

static const struct cdns_platform_data zynqmp_uart_def = {
.quirks = CDNS_UART_RXBS_SUPPORT, };

/* Match table for of_platform binding */
static const struct of_device_id cdns_uart_of_match[] = {
{ .compatible = "xlnx,xuartps", },
{ .compatible = "cdns,uart-r1p8", },
{ .compatible = "cdns,uart-r1p12", .data = &zynqmp_uart_def },
{}
};
MODULE_DEVICE_TABLE(of, cdns_uart_of_match);

/**
* cdns_uart_probe - Platform driver probe
* @pdev: Pointer to the platform device structure
Expand All @@ -1340,12 +1401,20 @@ static int cdns_uart_probe(struct platform_device *pdev)
struct uart_port *port;
struct resource *res;
struct cdns_uart *cdns_uart_data;
const struct of_device_id *match;

cdns_uart_data = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_data),
GFP_KERNEL);
if (!cdns_uart_data)
return -ENOMEM;

match = of_match_node(cdns_uart_of_match, pdev->dev.of_node);
if (match && match->data) {
const struct cdns_platform_data *data = match->data;

cdns_uart_data->quirks = data->quirks;
}

cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "pclk");
if (IS_ERR(cdns_uart_data->pclk)) {
cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "aper_clk");
Expand Down Expand Up @@ -1471,14 +1540,6 @@ static int cdns_uart_remove(struct platform_device *pdev)
return rc;
}

/* Match table for of_platform binding */
static const struct of_device_id cdns_uart_of_match[] = {
{ .compatible = "xlnx,xuartps", },
{ .compatible = "cdns,uart-r1p8", },
{}
};
MODULE_DEVICE_TABLE(of, cdns_uart_of_match);

static struct platform_driver cdns_uart_platform_driver = {
.probe = cdns_uart_probe,
.remove = cdns_uart_remove,
Expand Down

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