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tty/serial: atmel: add ISO7816 support
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When mode is set in atmel_config_iso7816() we backup last RS232 mode
for coming back to this mode if requested.
Also allow setup of T=0 and T=1 parameter and basic support in set_termios
function as well.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
[ludovic.desroches@microchip.com: rebase, add check on fidi ratio, checkpatch fixes]
Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Nicolas Ferre authored and Greg Kroah-Hartman committed Oct 2, 2018
1 parent ad8c0ea commit 377fedd
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Showing 2 changed files with 181 additions and 12 deletions.
190 changes: 179 additions & 11 deletions drivers/tty/serial/atmel_serial.c
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@
#include <linux/suspend.h>
#include <linux/mm.h>

#include <asm/div64.h>
#include <asm/io.h>
#include <asm/ioctls.h>

Expand Down Expand Up @@ -147,6 +148,8 @@ struct atmel_uart_port {
struct circ_buf rx_ring;

struct mctrl_gpios *gpios;
u32 backup_mode; /* MR saved during iso7816 operations */
u32 backup_brgr; /* BRGR saved during iso7816 operations */
unsigned int tx_done_mask;
u32 fifo_size;
u32 rts_high;
Expand All @@ -163,6 +166,10 @@ struct atmel_uart_port {
unsigned int pending_status;
spinlock_t lock_suspended;

/* ISO7816 */
unsigned int fidi_min;
unsigned int fidi_max;

#ifdef CONFIG_PM
struct {
u32 cr;
Expand Down Expand Up @@ -361,6 +368,127 @@ static int atmel_config_rs485(struct uart_port *port,
return 0;
}

static unsigned int atmel_calc_cd(struct uart_port *port,
struct serial_iso7816 *iso7816conf)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned int cd;
u64 mck_rate;

mck_rate = (u64)clk_get_rate(atmel_port->clk);
do_div(mck_rate, iso7816conf->clk);
cd = mck_rate;
return cd;
}

static unsigned int atmel_calc_fidi(struct uart_port *port,
struct serial_iso7816 *iso7816conf)
{
u64 fidi = 0;

if (iso7816conf->sc_fi && iso7816conf->sc_di) {
fidi = (u64)iso7816conf->sc_fi;
do_div(fidi, iso7816conf->sc_di);
}
return (u32)fidi;
}

/* Enable or disable the iso7816 support */
/* Called with interrupts disabled */
static int atmel_config_iso7816(struct uart_port *port,
struct serial_iso7816 *iso7816conf)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned int mode;
unsigned int cd, fidi;
int ret = 0;

/* Disable interrupts */
atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);

mode = atmel_uart_readl(port, ATMEL_US_MR);

if (iso7816conf->flags & SER_ISO7816_ENABLED) {
mode &= ~ATMEL_US_USMODE;

if (iso7816conf->tg > 255) {
dev_err(port->dev, "ISO7816: Timeguard exceeding 255\n");
memset(iso7816conf, 0, sizeof(struct serial_iso7816));
ret = -EINVAL;
goto err_out;
}

if ((iso7816conf->flags & SER_ISO7816_T_PARAM)
== SER_ISO7816_T(0)) {
mode |= ATMEL_US_USMODE_ISO7816_T0 | ATMEL_US_DSNACK;
} else if ((iso7816conf->flags & SER_ISO7816_T_PARAM)
== SER_ISO7816_T(1)) {
mode |= ATMEL_US_USMODE_ISO7816_T1 | ATMEL_US_INACK;
} else {
dev_err(port->dev, "ISO7816: Type not supported\n");
memset(iso7816conf, 0, sizeof(struct serial_iso7816));
ret = -EINVAL;
goto err_out;
}

mode &= ~(ATMEL_US_USCLKS | ATMEL_US_NBSTOP | ATMEL_US_PAR);

/* select mck clock, and output */
mode |= ATMEL_US_USCLKS_MCK | ATMEL_US_CLKO;
/* set parity for normal/inverse mode + max iterations */
mode |= ATMEL_US_PAR_EVEN | ATMEL_US_NBSTOP_1 | ATMEL_US_MAX_ITER(3);

cd = atmel_calc_cd(port, iso7816conf);
fidi = atmel_calc_fidi(port, iso7816conf);
if (fidi == 0) {
dev_warn(port->dev, "ISO7816 fidi = 0, Generator generates no signal\n");
} else if (fidi < atmel_port->fidi_min
|| fidi > atmel_port->fidi_max) {
dev_err(port->dev, "ISO7816 fidi = %u, value not supported\n", fidi);
memset(iso7816conf, 0, sizeof(struct serial_iso7816));
ret = -EINVAL;
goto err_out;
}

if (!(port->iso7816.flags & SER_ISO7816_ENABLED)) {
/* port not yet in iso7816 mode: store configuration */
atmel_port->backup_mode = atmel_uart_readl(port, ATMEL_US_MR);
atmel_port->backup_brgr = atmel_uart_readl(port, ATMEL_US_BRGR);
}

atmel_uart_writel(port, ATMEL_US_TTGR, iso7816conf->tg);
atmel_uart_writel(port, ATMEL_US_BRGR, cd);
atmel_uart_writel(port, ATMEL_US_FIDI, fidi);

atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS | ATMEL_US_RXEN);
atmel_port->tx_done_mask = ATMEL_US_TXEMPTY | ATMEL_US_NACK | ATMEL_US_ITERATION;
} else {
dev_dbg(port->dev, "Setting UART back to RS232\n");
/* back to last RS232 settings */
mode = atmel_port->backup_mode;
memset(iso7816conf, 0, sizeof(struct serial_iso7816));
atmel_uart_writel(port, ATMEL_US_TTGR, 0);
atmel_uart_writel(port, ATMEL_US_BRGR, atmel_port->backup_brgr);
atmel_uart_writel(port, ATMEL_US_FIDI, 0x174);

if (atmel_use_pdc_tx(port))
atmel_port->tx_done_mask = ATMEL_US_ENDTX |
ATMEL_US_TXBUFE;
else
atmel_port->tx_done_mask = ATMEL_US_TXRDY;
}

port->iso7816 = *iso7816conf;

atmel_uart_writel(port, ATMEL_US_MR, mode);

err_out:
/* Enable interrupts */
atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);

return ret;
}

/*
* Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
*/
Expand Down Expand Up @@ -480,8 +608,9 @@ static void atmel_stop_tx(struct uart_port *port)
/* Disable interrupts */
atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);

if ((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX))
if (((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
port->iso7816.flags & SER_ISO7816_ENABLED)
atmel_start_rx(port);
}

Expand All @@ -499,8 +628,9 @@ static void atmel_start_tx(struct uart_port *port)
return;

if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))
if ((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX))
if (((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
port->iso7816.flags & SER_ISO7816_ENABLED)
atmel_stop_rx(port);

if (atmel_use_pdc_tx(port))
Expand Down Expand Up @@ -798,8 +928,9 @@ static void atmel_complete_tx_dma(void *arg)
*/
if (!uart_circ_empty(xmit))
atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
else if ((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX)) {
else if (((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
port->iso7816.flags & SER_ISO7816_ENABLED) {
/* DMA done, stop TX, start RX for RS485 */
atmel_start_rx(port);
}
Expand Down Expand Up @@ -1282,6 +1413,9 @@ atmel_handle_status(struct uart_port *port, unsigned int pending,
wake_up_interruptible(&port->state->port.delta_msr_wait);
}
}

if (pending & (ATMEL_US_NACK | ATMEL_US_ITERATION))
dev_dbg(port->dev, "ISO7816 ERROR (0x%08x)\n", pending);
}

/*
Expand Down Expand Up @@ -1374,8 +1508,9 @@ static void atmel_tx_pdc(struct uart_port *port)
atmel_uart_writel(port, ATMEL_US_IER,
atmel_port->tx_done_mask);
} else {
if ((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX)) {
if (((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
port->iso7816.flags & SER_ISO7816_ENABLED) {
/* DMA done, stop TX, start RX for RS485 */
atmel_start_rx(port);
}
Expand Down Expand Up @@ -1727,6 +1862,22 @@ static void atmel_get_ip_name(struct uart_port *port)
atmel_port->has_frac_baudrate = true;
atmel_port->has_hw_timer = true;
atmel_port->rtor = ATMEL_US_RTOR;
version = atmel_uart_readl(port, ATMEL_US_VERSION);
switch (version) {
case 0x814: /* sama5d2 */
/* fall through */
case 0x701: /* sama5d4 */
atmel_port->fidi_min = 3;
atmel_port->fidi_max = 65535;
break;
case 0x502: /* sam9x5, sama5d3 */
atmel_port->fidi_min = 3;
atmel_port->fidi_max = 2047;
break;
default:
atmel_port->fidi_min = 1;
atmel_port->fidi_max = 2047;
}
} else if (name == dbgu_uart) {
dev_dbg(port->dev, "Dbgu or uart without hw timer\n");
} else {
Expand Down Expand Up @@ -2100,6 +2251,17 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
atmel_uart_writel(port, ATMEL_US_TTGR,
port->rs485.delay_rts_after_send);
mode |= ATMEL_US_USMODE_RS485;
} else if (port->iso7816.flags & SER_ISO7816_ENABLED) {
atmel_uart_writel(port, ATMEL_US_TTGR, port->iso7816.tg);
/* select mck clock, and output */
mode |= ATMEL_US_USCLKS_MCK | ATMEL_US_CLKO;
/* set max iterations */
mode |= ATMEL_US_MAX_ITER(3);
if ((port->iso7816.flags & SER_ISO7816_T_PARAM)
== SER_ISO7816_T(0))
mode |= ATMEL_US_USMODE_ISO7816_T0;
else
mode |= ATMEL_US_USMODE_ISO7816_T1;
} else if (termios->c_cflag & CRTSCTS) {
/* RS232 with hardware handshake (RTS/CTS) */
if (atmel_use_fifo(port) &&
Expand Down Expand Up @@ -2176,7 +2338,8 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
}
quot = cd | fp << ATMEL_US_FP_OFFSET;

atmel_uart_writel(port, ATMEL_US_BRGR, quot);
if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
atmel_uart_writel(port, ATMEL_US_BRGR, quot);
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
atmel_port->tx_stopped = false;
Expand Down Expand Up @@ -2357,6 +2520,7 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
port->mapbase = mpdev->resource[0].start;
port->irq = mpdev->resource[1].start;
port->rs485_config = atmel_config_rs485;
port->iso7816_config = atmel_config_iso7816;
port->membase = NULL;

memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));
Expand All @@ -2380,8 +2544,12 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
/* only enable clock when USART is in use */
}

/* Use TXEMPTY for interrupt when rs485 else TXRDY or ENDTX|TXBUFE */
if (port->rs485.flags & SER_RS485_ENABLED)
/*
* Use TXEMPTY for interrupt when rs485 or ISO7816 else TXRDY or
* ENDTX|TXBUFE
*/
if (port->rs485.flags & SER_RS485_ENABLED ||
port->iso7816.flags & SER_ISO7816_ENABLED)
atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
else if (atmel_use_pdc_tx(port)) {
port->fifosize = PDC_BUFFER_SIZE;
Expand Down
3 changes: 2 additions & 1 deletion drivers/tty/serial/atmel_serial.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,8 @@
#define ATMEL_US_OVER BIT(19) /* Oversampling Mode */
#define ATMEL_US_INACK BIT(20) /* Inhibit Non Acknowledge */
#define ATMEL_US_DSNACK BIT(21) /* Disable Successive NACK */
#define ATMEL_US_MAX_ITER GENMASK(26, 24) /* Max Iterations */
#define ATMEL_US_MAX_ITER_MASK GENMASK(26, 24) /* Max Iterations */
#define ATMEL_US_MAX_ITER(n) (((n) << 24) & ATMEL_US_MAX_ITER_MASK)
#define ATMEL_US_FILTER BIT(28) /* Infrared Receive Line Filter */

#define ATMEL_US_IER 0x08 /* Interrupt Enable Register */
Expand Down

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