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Subject[PATCH v2 2/2] serial: msm: Add support for UARTDM cores
Date
Add support for the next-generation version of the MSM UART
to the msm_serial driver. This version of the hardware is
similar to the original version, but has some DMA
capabilities that are used in PIO mode in this driver.

Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
---
V2 Address code review comments
* Improve clock control handling
* Improved error and stats reporting
* Remove old, non-working error reporting code
* General code cleanup

Proper, precise error/break reporting is not supported
on UARTDM cores due to hardware limitations.

drivers/serial/msm_serial.c | 286 +++++++++++++++++++++++++++++++++++++------
drivers/serial/msm_serial.h | 28 ++++-
2 files changed, 269 insertions(+), 45 deletions(-)

diff --git a/drivers/serial/msm_serial.c b/drivers/serial/msm_serial.c
index 8e43a7b..bfee9b4 100644
--- a/drivers/serial/msm_serial.c
+++ b/drivers/serial/msm_serial.c
@@ -3,6 +3,7 @@
*
* Copyright (C) 2007 Google, Inc.
* Author: Robert Love <rlove@google.com>
+ * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
@@ -31,6 +32,7 @@
#include <linux/serial.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
+#include <linux/delay.h>

#include "msm_serial.h"

@@ -38,9 +40,20 @@ struct msm_port {
struct uart_port uart;
char name[16];
struct clk *clk;
+ struct clk *pclk;
unsigned int imr;
+ unsigned int *gsbi_base;
+ int is_uartdm;
+ unsigned int old_snap_state;
};

+static inline void wait_for_xmitr(struct uart_port *port, int bits)
+{
+ if (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY))
+ while ((msm_read(port, UART_ISR) & bits) != bits)
+ cpu_relax();
+}
+
static void msm_stop_tx(struct uart_port *port)
{
struct msm_port *msm_port = UART_TO_MSM(port);
@@ -73,6 +86,61 @@ static void msm_enable_ms(struct uart_port *port)
msm_write(port, msm_port->imr, UART_IMR);
}

+static void handle_rx_dm(struct uart_port *port, unsigned int misr)
+{
+ struct tty_struct *tty = port->state->port.tty;
+ unsigned int sr;
+ int count = 0;
+ struct msm_port *msm_port = UART_TO_MSM(port);
+
+ if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
+ port->icount.overrun++;
+ tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+ msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
+ }
+
+ if (misr & UART_IMR_RXSTALE) {
+ count = msm_read(port, UARTDM_RX_TOTAL_SNAP) -
+ msm_port->old_snap_state;
+ msm_port->old_snap_state = 0;
+ } else {
+ count = 4 * (msm_read(port, UART_RFWR));
+ msm_port->old_snap_state += count;
+ }
+
+ /* TODO: Precise error reporting */
+
+ port->icount.rx += count;
+
+ while (count > 0) {
+ unsigned int c;
+
+ sr = msm_read(port, UART_SR);
+ if ((sr & UART_SR_RX_READY) == 0) {
+ msm_port->old_snap_state -= count;
+ break;
+ }
+ c = msm_read(port, UARTDM_RF);
+ if (sr & UART_SR_RX_BREAK) {
+ port->icount.brk++;
+ if (uart_handle_break(port))
+ continue;
+ } else if (sr & UART_SR_PAR_FRAME_ERR)
+ port->icount.frame++;
+
+ /* TODO: handle sysrq */
+ tty_insert_flip_string(tty, (char *) &c,
+ (count > 4) ? 4 : count);
+ count -= 4;
+ }
+
+ tty_flip_buffer_push(tty);
+ if (misr & (UART_IMR_RXSTALE))
+ msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
+ msm_write(port, 0xFFFFFF, UARTDM_DMRX);
+ msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
+}
+
static void handle_rx(struct uart_port *port)
{
struct tty_struct *tty = port->state->port.tty;
@@ -121,6 +189,12 @@ static void handle_rx(struct uart_port *port)
tty_flip_buffer_push(tty);
}

+static void reset_dm_count(struct uart_port *port)
+{
+ wait_for_xmitr(port, UART_ISR_TX_READY);
+ msm_write(port, 1, UARTDM_NCF_TX);
+}
+
static void handle_tx(struct uart_port *port)
{
struct circ_buf *xmit = &port->state->xmit;
@@ -128,11 +202,18 @@ static void handle_tx(struct uart_port *port)
int sent_tx;

if (port->x_char) {
- msm_write(port, port->x_char, UART_TF);
+ if (msm_port->is_uartdm)
+ reset_dm_count(port);
+
+ msm_write(port, port->x_char,
+ msm_port->is_uartdm ? UARTDM_TF : UART_TF);
port->icount.tx++;
port->x_char = 0;
}

+ if (msm_port->is_uartdm)
+ reset_dm_count(port);
+
while (msm_read(port, UART_SR) & UART_SR_TX_READY) {
if (uart_circ_empty(xmit)) {
/* disable tx interrupts */
@@ -140,8 +221,11 @@ static void handle_tx(struct uart_port *port)
msm_write(port, msm_port->imr, UART_IMR);
break;
}
+ msm_write(port, xmit->buf[xmit->tail],
+ msm_port->is_uartdm ? UARTDM_TF : UART_TF);

- msm_write(port, xmit->buf[xmit->tail], UART_TF);
+ if (msm_port->is_uartdm)
+ reset_dm_count(port);

xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
@@ -169,8 +253,12 @@ static irqreturn_t msm_irq(int irq, void *dev_id)
misr = msm_read(port, UART_MISR);
msm_write(port, 0, UART_IMR); /* disable interrupt */

- if (misr & (UART_IMR_RXLEV | UART_IMR_RXSTALE))
- handle_rx(port);
+ if (misr & (UART_IMR_RXLEV | UART_IMR_RXSTALE)) {
+ if (msm_port->is_uartdm)
+ handle_rx_dm(port, misr);
+ else
+ handle_rx(port);
+ }
if (misr & UART_IMR_TXLEV)
handle_tx(port);
if (misr & UART_IMR_DELTA_CTS)
@@ -192,10 +280,21 @@ static unsigned int msm_get_mctrl(struct uart_port *port)
return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR | TIOCM_RTS;
}

-static void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
+
+static void msm_reset(struct uart_port *port)
{
- unsigned int mr;
+ /* reset everything */
+ msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
+ msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
+ msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
+ 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);
+}

+void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+ unsigned int mr;
mr = msm_read(port, UART_MR1);

if (!(mctrl & TIOCM_RTS)) {
@@ -219,6 +318,7 @@ static void msm_break_ctl(struct uart_port *port, int break_ctl)
static int msm_set_baud_rate(struct uart_port *port, unsigned int baud)
{
unsigned int baud_code, rxstale, watermark;
+ struct msm_port *msm_port = UART_TO_MSM(port);

switch (baud) {
case 300:
@@ -273,6 +373,9 @@ static int msm_set_baud_rate(struct uart_port *port, unsigned int baud)
break;
}

+ if (msm_port->is_uartdm)
+ msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
+
msm_write(port, baud_code, UART_CSR);

/* RX stale watermark */
@@ -288,25 +391,23 @@ static int msm_set_baud_rate(struct uart_port *port, unsigned int baud)
/* set TX watermark */
msm_write(port, 10, UART_TFWR);

+ if (msm_port->is_uartdm) {
+ msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
+ msm_write(port, 0xFFFFFF, UARTDM_DMRX);
+ msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
+ }
+
return baud;
}

-static void msm_reset(struct uart_port *port)
-{
- /* reset everything */
- msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
- msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
- msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
- 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);
-}

static void msm_init_clock(struct uart_port *port)
{
struct msm_port *msm_port = UART_TO_MSM(port);

clk_enable(msm_port->clk);
+ if (!IS_ERR(msm_port->pclk))
+ clk_enable(msm_port->pclk);
msm_serial_set_mnd_regs(port);
}

@@ -347,15 +448,31 @@ static int msm_startup(struct uart_port *port)
msm_write(port, data, UART_IPR);
}

- msm_reset(port);
+ data = 0;
+ if (!port->cons || (port->cons && !(port->cons->flags & CON_ENABLED))) {
+ msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR);
+ msm_reset(port);
+ data = UART_CR_TX_ENABLE;
+ }
+
+ data |= UART_CR_RX_ENABLE;
+ msm_write(port, data, UART_CR); /* enable TX & RX */

- msm_write(port, 0x05, UART_CR); /* enable TX & RX */
+ /* Make sure IPR is not 0 to start with*/
+ if (msm_port->is_uartdm)
+ msm_write(port, UART_IPR_STALE_LSB, UART_IPR);

/* turn on RX and CTS interrupts */
msm_port->imr = UART_IMR_RXLEV | UART_IMR_RXSTALE |
UART_IMR_CURRENT_CTS;
- msm_write(port, msm_port->imr, UART_IMR);

+ if (msm_port->is_uartdm) {
+ msm_write(port, 0xFFFFFF, UARTDM_DMRX);
+ msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
+ msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
+ }
+
+ msm_write(port, msm_port->imr, UART_IMR);
return 0;
}

@@ -384,7 +501,7 @@ static void msm_set_termios(struct uart_port *port, struct ktermios *termios,
baud = msm_set_baud_rate(port, baud);
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);
-
+
/* calculate parity */
mr = msm_read(port, UART_MR2);
mr &= ~UART_MR2_PARITY_MODE;
@@ -454,48 +571,105 @@ static const char *msm_type(struct uart_port *port)
static void msm_release_port(struct uart_port *port)
{
struct platform_device *pdev = to_platform_device(port->dev);
- struct resource *resource;
+ struct msm_port *msm_port = UART_TO_MSM(port);
+ struct resource *uart_resource;
+ struct resource *gsbi_resource;
resource_size_t size;

- resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (unlikely(!resource))
+ uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (unlikely(!uart_resource))
return;
- size = resource->end - resource->start + 1;
+ size = resource_size(uart_resource);

release_mem_region(port->mapbase, size);
iounmap(port->membase);
port->membase = NULL;
+
+ if (msm_port->gsbi_base) {
+ iowrite32(GSBI_PROTOCOL_IDLE, msm_port->gsbi_base +
+ GSBI_CONTROL);
+
+ gsbi_resource = platform_get_resource_byname(pdev,
+ IORESOURCE_MEM,
+ "gsbi_resource");
+
+ if (unlikely(!gsbi_resource))
+ return;
+
+ size = resource_size(gsbi_resource);
+ release_mem_region(gsbi_resource->start, size);
+ iounmap(msm_port->gsbi_base);
+ msm_port->gsbi_base = NULL;
+ }
}

static int msm_request_port(struct uart_port *port)
{
+ struct msm_port *msm_port = UART_TO_MSM(port);
struct platform_device *pdev = to_platform_device(port->dev);
- struct resource *resource;
+ struct resource *uart_resource;
+ struct resource *gsbi_resource;
resource_size_t size;
+ int ret;

- resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (unlikely(!resource))
+ uart_resource = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+ "uart_resource");
+ if (unlikely(!uart_resource))
return -ENXIO;
- size = resource->end - resource->start + 1;

- if (unlikely(!request_mem_region(port->mapbase, size, "msm_serial")))
+ size = resource_size(uart_resource);
+
+ if (!request_mem_region(port->mapbase, size, "msm_serial"))
return -EBUSY;

port->membase = ioremap(port->mapbase, size);
if (!port->membase) {
- release_mem_region(port->mapbase, size);
- return -EBUSY;
+ ret = -EBUSY;
+ goto fail_release_port;
+ }
+
+ gsbi_resource = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+ "gsbi_resource");
+ /* Is this a GSBI-based port? */
+ if (gsbi_resource) {
+ size = resource_size(gsbi_resource);
+
+ if (!request_mem_region(gsbi_resource->start, size,
+ "msm_serial")) {
+ ret = -EBUSY;
+ goto fail_release_port;
+ }
+
+ msm_port->gsbi_base = ioremap(gsbi_resource->start, size);
+ if (!msm_port->gsbi_base) {
+ ret = -EBUSY;
+ goto fail_release_gsbi;
+ }
}

return 0;
+
+fail_release_gsbi:
+ release_mem_region(gsbi_resource->start, size);
+fail_release_port:
+ release_mem_region(port->mapbase, size);
+ return ret;
}

static void msm_config_port(struct uart_port *port, int flags)
{
+ struct msm_port *msm_port = UART_TO_MSM(port);
+ int ret;
if (flags & UART_CONFIG_TYPE) {
port->type = PORT_MSM;
- msm_request_port(port);
+ ret = msm_request_port(port);
+ if (ret)
+ return;
}
+
+ if (msm_port->is_uartdm)
+ iowrite32(GSBI_PROTOCOL_UART, msm_port->gsbi_base +
+ GSBI_CONTROL);
}

static int msm_verify_port(struct uart_port *port, struct serial_struct *ser)
@@ -515,9 +689,13 @@ static void msm_power(struct uart_port *port, unsigned int state,
switch (state) {
case 0:
clk_enable(msm_port->clk);
+ if (!IS_ERR(msm_port->pclk))
+ clk_enable(msm_port->pclk);
break;
case 3:
clk_disable(msm_port->clk);
+ if (!IS_ERR(msm_port->pclk))
+ clk_disable(msm_port->pclk);
break;
default:
printk(KERN_ERR "msm_serial: Unknown PM state %d\n", state);
@@ -550,7 +728,7 @@ static struct msm_port msm_uart_ports[] = {
.iotype = UPIO_MEM,
.ops = &msm_uart_pops,
.flags = UPF_BOOT_AUTOCONF,
- .fifosize = 512,
+ .fifosize = 64,
.line = 0,
},
},
@@ -559,7 +737,7 @@ static struct msm_port msm_uart_ports[] = {
.iotype = UPIO_MEM,
.ops = &msm_uart_pops,
.flags = UPF_BOOT_AUTOCONF,
- .fifosize = 512,
+ .fifosize = 64,
.line = 1,
},
},
@@ -585,9 +763,14 @@ static inline struct uart_port *get_port_from_line(unsigned int line)

static void msm_console_putchar(struct uart_port *port, int c)
{
+ struct msm_port *msm_port = UART_TO_MSM(port);
+
+ if (msm_port->is_uartdm)
+ reset_dm_count(port);
+
while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
;
- msm_write(port, c, UART_TF);
+ msm_write(port, c, msm_port->is_uartdm ? UARTDM_TF : UART_TF);
}

static void msm_console_write(struct console *co, const char *s,
@@ -609,12 +792,14 @@ static void msm_console_write(struct console *co, const char *s,
static int __init msm_console_setup(struct console *co, char *options)
{
struct uart_port *port;
+ struct msm_port *msm_port;
int baud, flow, bits, parity;

if (unlikely(co->index >= UART_NR || co->index < 0))
return -ENXIO;

port = get_port_from_line(co->index);
+ msm_port = UART_TO_MSM(port);

if (unlikely(!port->membase))
return -ENXIO;
@@ -638,6 +823,11 @@ static int __init msm_console_setup(struct console *co, char *options)

msm_reset(port);

+ if (msm_port->is_uartdm) {
+ msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR);
+ msm_write(port, UART_CR_TX_ENABLE, UART_CR);
+ }
+
printk(KERN_INFO "msm_serial: console setup on port #%d\n", port->line);

return uart_set_options(port, co, baud, parity, bits, flow);
@@ -685,14 +875,32 @@ static int __init msm_serial_probe(struct platform_device *pdev)
port->dev = &pdev->dev;
msm_port = UART_TO_MSM(port);

- msm_port->clk = clk_get(&pdev->dev, "uart_clk");
- if (IS_ERR(msm_port->clk))
- return PTR_ERR(msm_port->clk);
+ if (platform_get_resource_byname(pdev, IORESOURCE_MEM, "gsbi_resource"))
+ msm_port->is_uartdm = 1;
+ else
+ msm_port->is_uartdm = 0;
+
+ if (msm_port->is_uartdm) {
+ msm_port->clk = clk_get(&pdev->dev, "gsbi_uart_clk");
+ msm_port->pclk = clk_get(&pdev->dev, "gsbi_pclk");
+ } else {
+ msm_port->clk = clk_get(&pdev->dev, "uart_clk");
+ msm_port->pclk = ERR_PTR(-ENOENT);
+ }
+
+ if (unlikely(IS_ERR(msm_port->clk) || (IS_ERR(msm_port->pclk) &&
+ msm_port->is_uartdm)))
+ return PTR_ERR(msm_port->clk);
+
+ if (msm_port->is_uartdm)
+ clk_set_rate(msm_port->clk, 7372800);
+
port->uartclk = clk_get_rate(msm_port->clk);
printk(KERN_INFO "uartclk = %d\n", port->uartclk);


- resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ resource = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+ "uart_resource");
if (unlikely(!resource))
return -ENXIO;
port->mapbase = resource->start;
diff --git a/drivers/serial/msm_serial.h b/drivers/serial/msm_serial.h
index f6ca9ca..9b8dc5d 100644
--- a/drivers/serial/msm_serial.h
+++ b/drivers/serial/msm_serial.h
@@ -3,6 +3,7 @@
*
* Copyright (C) 2007 Google, Inc.
* Author: Robert Love <rlove@google.com>
+ * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
@@ -54,6 +55,7 @@
#define UART_CSR_300 0x22

#define UART_TF 0x000C
+#define UARTDM_TF 0x0070

#define UART_CR 0x0010
#define UART_CR_CMD_NULL (0 << 4)
@@ -64,14 +66,17 @@
#define UART_CR_CMD_START_BREAK (5 << 4)
#define UART_CR_CMD_STOP_BREAK (6 << 4)
#define UART_CR_CMD_RESET_CTS (7 << 4)
+#define UART_CR_CMD_RESET_STALE_INT (8 << 4)
#define UART_CR_CMD_PACKET_MODE (9 << 4)
#define UART_CR_CMD_MODE_RESET (12 << 4)
#define UART_CR_CMD_SET_RFR (13 << 4)
#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_TX_DISABLE (1 << 3)
-#define UART_CR_TX_ENABLE (1 << 3)
-#define UART_CR_RX_DISABLE (1 << 3)
-#define UART_CR_RX_ENABLE (1 << 3)
+#define UART_CR_TX_ENABLE (1 << 2)
+#define UART_CR_RX_DISABLE (1 << 1)
+#define UART_CR_RX_ENABLE (1 << 0)

#define UART_IMR 0x0014
#define UART_IMR_TXLEV (1 << 0)
@@ -110,9 +115,20 @@
#define UART_SR_RX_FULL (1 << 1)
#define UART_SR_RX_READY (1 << 0)

-#define UART_RF 0x000C
-#define UART_MISR 0x0010
-#define UART_ISR 0x0014
+#define UART_RF 0x000C
+#define UARTDM_RF 0x0070
+#define UART_MISR 0x0010
+#define UART_ISR 0x0014
+#define UART_ISR_TX_READY (1 << 7)
+
+#define GSBI_CONTROL 0x0
+#define GSBI_PROTOCOL_CODE 0x30
+#define GSBI_PROTOCOL_UART 0x40
+#define GSBI_PROTOCOL_IDLE 0x0
+
+#define UARTDM_DMRX 0x34
+#define UARTDM_NCF_TX 0x40
+#define UARTDM_RX_TOTAL_SNAP 0x38

#define UART_TO_MSM(uart_port) ((struct msm_port *) uart_port)

--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.


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