serial: msm: Add support for UARTDM cores

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>
Signed-off-by: David Brown <davidb@codeaurora.org>

1 files changed, 247 insertions, 39 deletions

diff --git a/drivers/serial/msm_serial.c b/drivers/serial/msm_serial.c
index 8e43a7b69e64..bfee9b4c6661 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;