tty/serial: atmel: add ISO7816 support

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>

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 267d4d1de3f877f0bb8d5060bf43921222f23f2a..05147fe243434a52e4ca827227d95dc1f6a0f2e6 100644 (file)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -34,6 +34,7 @@
 #include <linux/suspend.h>
 #include <linux/mm.h>
 
+#include <asm/div64.h>
 #include <asm/io.h>
 #include <asm/ioctls.h>
 
@@ -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;
@@ -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;
@@ -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.
  */
@@ -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);
 }
 
@@ -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))
@@ -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);
        }
@@ -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);
 }
 
 /*
@@ -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);
                }
@@ -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 {
@@ -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) &&
@@ -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;
@@ -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));
@@ -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;

diff --git a/drivers/tty/serial/atmel_serial.h b/drivers/tty/serial/atmel_serial.h
index ba3a2437cde4c68d99ff77d229f55fe75e1987e5..d811d4f2d0c06c8ffe0370093dc161651c222524 100644 (file)
--- a/drivers/tty/serial/atmel_serial.h
+++ b/drivers/tty/serial/atmel_serial.h
@@ -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 */