msm_serial: Add support for poll_{get,put}_char()

Implement the polling functionality for the MSM serial driver.
This allows us to use KGDB on this hardware.

Cc: David Brown <davidb@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index b5d779c..053b98e 100644 (file)
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -39,6 +39,13 @@
 
 #include "msm_serial.h"
 
+enum {
+       UARTDM_1P1 = 1,
+       UARTDM_1P2,
+       UARTDM_1P3,
+       UARTDM_1P4,
+};
+
 struct msm_port {
        struct uart_port        uart;
        char                    name[16];
@@ -309,6 +316,8 @@ static unsigned int msm_get_mctrl(struct uart_port *port)
 
 static void msm_reset(struct uart_port *port)
 {
+       struct msm_port *msm_port = UART_TO_MSM(port);
+
        /* reset everything */
        msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
        msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
@@ -316,6 +325,10 @@ static void msm_reset(struct uart_port *port)
        msm_write(port, UART_CR_CMD_RESET_BREAK_INT, UART_CR);
        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
        msm_write(port, UART_CR_CMD_SET_RFR, UART_CR);
+
+       /* Disable DM modes */
+       if (msm_port->is_uartdm)
+               msm_write(port, 0, UARTDM_DMEN);
 }
 
 static void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
@@ -711,6 +724,117 @@ static void msm_power(struct uart_port *port, unsigned int state,
        }
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+static int msm_poll_init(struct uart_port *port)
+{
+       struct msm_port *msm_port = UART_TO_MSM(port);
+
+       /* Enable single character mode on RX FIFO */
+       if (msm_port->is_uartdm >= UARTDM_1P4)
+               msm_write(port, UARTDM_DMEN_RX_SC_ENABLE, UARTDM_DMEN);
+
+       return 0;
+}
+
+static int msm_poll_get_char_single(struct uart_port *port)
+{
+       struct msm_port *msm_port = UART_TO_MSM(port);
+       unsigned int rf_reg = msm_port->is_uartdm ? UARTDM_RF : UART_RF;
+
+       if (!(msm_read(port, UART_SR) & UART_SR_RX_READY))
+               return NO_POLL_CHAR;
+       else
+               return msm_read(port, rf_reg) & 0xff;
+}
+
+static int msm_poll_get_char_dm_1p3(struct uart_port *port)
+{
+       int c;
+       static u32 slop;
+       static int count;
+       unsigned char *sp = (unsigned char *)&slop;
+
+       /* Check if a previous read had more than one char */
+       if (count) {
+               c = sp[sizeof(slop) - count];
+               count--;
+       /* Or if FIFO is empty */
+       } else if (!(msm_read(port, UART_SR) & UART_SR_RX_READY)) {
+               /*
+                * If RX packing buffer has less than a word, force stale to
+                * push contents into RX FIFO
+                */
+               count = msm_read(port, UARTDM_RXFS);
+               count = (count >> UARTDM_RXFS_BUF_SHIFT) & UARTDM_RXFS_BUF_MASK;
+               if (count) {
+                       msm_write(port, UART_CR_CMD_FORCE_STALE, UART_CR);
+                       slop = msm_read(port, UARTDM_RF);
+                       c = sp[0];
+                       count--;
+               } else {
+                       c = NO_POLL_CHAR;
+               }
+       /* FIFO has a word */
+       } else {
+               slop = msm_read(port, UARTDM_RF);
+               c = sp[0];
+               count = sizeof(slop) - 1;
+       }
+
+       return c;
+}
+
+static int msm_poll_get_char(struct uart_port *port)
+{
+       u32 imr;
+       int c;
+       struct msm_port *msm_port = UART_TO_MSM(port);
+
+       /* Disable all interrupts */
+       imr = msm_read(port, UART_IMR);
+       msm_write(port, 0, UART_IMR);
+
+       if (msm_port->is_uartdm == UARTDM_1P3)
+               c = msm_poll_get_char_dm_1p3(port);
+       else
+               c = msm_poll_get_char_single(port);
+
+       /* Enable interrupts */
+       msm_write(port, imr, UART_IMR);
+
+       return c;
+}
+
+static void msm_poll_put_char(struct uart_port *port, unsigned char c)
+{
+       u32 imr;
+       struct msm_port *msm_port = UART_TO_MSM(port);
+
+       /* Disable all interrupts */
+       imr = msm_read(port, UART_IMR);
+       msm_write(port, 0, UART_IMR);
+
+       if (msm_port->is_uartdm)
+               reset_dm_count(port, 1);
+
+       /* Wait until FIFO is empty */
+       while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
+               cpu_relax();
+
+       /* Write a character */
+       msm_write(port, c, msm_port->is_uartdm ? UARTDM_TF : UART_TF);
+
+       /* Wait until FIFO is empty */
+       while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
+               cpu_relax();
+
+       /* Enable interrupts */
+       msm_write(port, imr, UART_IMR);
+
+       return;
+}
+#endif
+
 static struct uart_ops msm_uart_pops = {
        .tx_empty = msm_tx_empty,
        .set_mctrl = msm_set_mctrl,
@@ -729,6 +853,11 @@ static struct uart_ops msm_uart_pops = {
        .config_port = msm_config_port,
        .verify_port = msm_verify_port,
        .pm = msm_power,
+#ifdef CONFIG_CONSOLE_POLL
+       .poll_init = msm_poll_init,
+       .poll_get_char  = msm_poll_get_char,
+       .poll_put_char  = msm_poll_put_char,
+#endif
 };
 
 static struct msm_port msm_uart_ports[] = {
@@ -900,7 +1029,10 @@ static struct uart_driver msm_uart_driver = {
 static atomic_t msm_uart_next_id = ATOMIC_INIT(0);
 
 static const struct of_device_id msm_uartdm_table[] = {
-       { .compatible = "qcom,msm-uartdm" },
+       { .compatible = "qcom,msm-uartdm-v1.1", .data = (void *)UARTDM_1P1 },
+       { .compatible = "qcom,msm-uartdm-v1.2", .data = (void *)UARTDM_1P2 },
+       { .compatible = "qcom,msm-uartdm-v1.3", .data = (void *)UARTDM_1P3 },
+       { .compatible = "qcom,msm-uartdm-v1.4", .data = (void *)UARTDM_1P4 },
        { }
 };
 
@@ -909,6 +1041,7 @@ static int __init msm_serial_probe(struct platform_device *pdev)
        struct msm_port *msm_port;
        struct resource *resource;
        struct uart_port *port;
+       const struct of_device_id *id;
        int irq;
 
        if (pdev->id == -1)
@@ -923,8 +1056,9 @@ static int __init msm_serial_probe(struct platform_device *pdev)
        port->dev = &pdev->dev;
        msm_port = UART_TO_MSM(port);
 
-       if (of_match_device(msm_uartdm_table, &pdev->dev))
-               msm_port->is_uartdm = 1;
+       id = of_match_device(msm_uartdm_table, &pdev->dev);
+       if (id)
+               msm_port->is_uartdm = (unsigned long)id->data;
        else
                msm_port->is_uartdm = 0;
 

diff --git a/drivers/tty/serial/msm_serial.h b/drivers/tty/serial/msm_serial.h
index 469fda5..1e9b68b 100644 (file)
--- a/drivers/tty/serial/msm_serial.h
+++ b/drivers/tty/serial/msm_serial.h
@@ -59,6 +59,7 @@
 #define UART_CR_CMD_RESET_RFR          (14 << 4)
 #define UART_CR_CMD_PROTECTION_EN      (16 << 4)
 #define UART_CR_CMD_STALE_EVENT_ENABLE (80 << 4)
+#define UART_CR_CMD_FORCE_STALE                (4 << 8)
 #define UART_CR_CMD_RESET_TX_READY     (3 << 8)
 #define UART_CR_TX_DISABLE             (1 << 3)
 #define UART_CR_TX_ENABLE              (1 << 2)
@@ -113,6 +114,14 @@
 #define GSBI_PROTOCOL_UART     0x40
 #define GSBI_PROTOCOL_IDLE     0x0
 
+#define UARTDM_RXFS            0x50
+#define UARTDM_RXFS_BUF_SHIFT  0x7
+#define UARTDM_RXFS_BUF_MASK   0x7
+
+#define UARTDM_DMEN            0x3C
+#define UARTDM_DMEN_RX_SC_ENABLE BIT(5)
+#define UARTDM_DMEN_TX_SC_ENABLE BIT(4)
+
 #define UARTDM_DMRX            0x34
 #define UARTDM_NCF_TX          0x40
 #define UARTDM_RX_TOTAL_SNAP   0x38