[PATCH] msm_serial: Add support for poll_{get,put}_char()
Stephen Boyd
sboyd at codeaurora.org
Tue Jan 14 15:34:55 EST 2014
Implement the polling functionality for the MSM serial driver.
This allows us to use KGDB on this hardware.
Cc: David Brown <davidb at codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd at codeaurora.org>
---
drivers/tty/serial/msm_serial.c | 140 +++++++++++++++++++++++++++++++++++++++-
drivers/tty/serial/msm_serial.h | 9 +++
2 files changed, 146 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index b5d779cd3c2b..053b98eb46c8 100644
--- 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 469fda50ac63..1e9b68b6f9eb 100644
--- 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
--
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