diff mbox

[V3,28/41] xen/arm: Add generic UART to get the device in the device tree

Message ID 1368152307-598-29-git-send-email-julien.grall@linaro.org
State Superseded, archived
Headers show

Commit Message

Julien Grall May 10, 2013, 2:18 a.m. UTC 
This generic UART will find the right UART via xen command line
with dtuart=myserial.

"myserial" is the alias of the UART in the device tree. Xen will retrieve
the information via the device tree and call the initialization function for
this specific UART thanks to the device API.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
CC: keir@xen.org

Changes in v3:
    - Rename arm-uart.c (resp. arm_uart_init) to dt-uart.c (resp. dt_uart_init)
    - Remove serial_arm_defaults and replace by a string options
    - Let the specific UART driver to get its base address in the DT
    - Add SERHND_DTUART. The value is stolen to SERHND_COM1. Bump the
    value would needs some rework...

Changes in v2:
    - Use dtuart parameter instead of com1. The first one is more arm
    while the latter is more x86
---
 xen/arch/arm/setup.c         |    3 +-
 xen/drivers/char/Makefile    |    1 +
 xen/drivers/char/dt-uart.c   |   69 ++++++++++++++++++++++++++++++++++++++++++
 xen/drivers/char/serial.c    |    6 ++++
 xen/include/asm-arm/config.h |    2 +-
 xen/include/xen/serial.h     |    5 ++-
 6 files changed, 83 insertions(+), 3 deletions(-)
 create mode 100644 xen/drivers/char/dt-uart.c

Comments

Ian Campbell May 10, 2013, 9:32 a.m. UTC | #1 
On Fri, 2013-05-10 at 03:18 +0100, Julien Grall wrote:
> This generic UART will find the right UART via xen command line
> with dtuart=myserial.
> 
> "myserial" is the alias of the UART in the device tree. Xen will retrieve
> the information via the device tree and call the initialization function for
> this specific UART thanks to the device API.
> 
> Signed-off-by: Julien Grall <julien.grall@linaro.org>


> CC: keir@xen.org
> 
> Changes in v3:
>     - Rename arm-uart.c (resp. arm_uart_init) to dt-uart.c (resp. dt_uart_init)
>     - Remove serial_arm_defaults and replace by a string options
>     - Let the specific UART driver to get its base address in the DT
>     - Add SERHND_DTUART. The value is stolen to SERHND_COM1. Bump the
>     value would needs some rework...

This is because of the need to encode the value in 2 bits? Due to
SERHND_IDX etc, is the rework more than simply changing the mask and
bumping the flags up and increasing the size of the com array?

I'm OK with this for 4.3 if Keir is:

Acked-by: Ian Campbell <ian.campbell@citrix.com>
Julien Grall May 10, 2013, 12:47 p.m. UTC | #2 
On 05/10/2013 10:32 AM, Ian Campbell wrote:

> On Fri, 2013-05-10 at 03:18 +0100, Julien Grall wrote:
>> This generic UART will find the right UART via xen command line
>> with dtuart=myserial.
>>
>> "myserial" is the alias of the UART in the device tree. Xen will retrieve
>> the information via the device tree and call the initialization function for
>> this specific UART thanks to the device API.
>>
>> Signed-off-by: Julien Grall <julien.grall@linaro.org>
> 
> 
>> CC: keir@xen.org
>>
>> Changes in v3:
>>     - Rename arm-uart.c (resp. arm_uart_init) to dt-uart.c (resp. dt_uart_init)
>>     - Remove serial_arm_defaults and replace by a string options
>>     - Let the specific UART driver to get its base address in the DT
>>     - Add SERHND_DTUART. The value is stolen to SERHND_COM1. Bump the
>>     value would needs some rework...
> 
> This is because of the need to encode the value in 2 bits? Due to
> SERHND_IDX etc, is the rework more than simply changing the mask and
> bumping the flags up and increasing the size of the com array?

The console code is able to handle one serial at time so, I don't
understand why we need to "waste" another memory space for a new kind of
serial.

> I'm OK with this for 4.3 if Keir is:
> 
> Acked-by: Ian Campbell <ian.campbell@citrix.com>
> 
>
diff mbox

Patch

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index fc53117..2e331d3 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -436,8 +436,9 @@  void __init start_xen(unsigned long boot_phys_offset,
 #ifdef EARLY_UART_ADDRESS
     /* TODO Need to get device tree or command line for UART address */
     pl011_init(0, FIXMAP_ADDR(FIXMAP_CONSOLE));
-    console_init_preirq();
 #endif
+    dt_uart_init();
+    console_init_preirq();
 
     system_state = SYS_STATE_boot;
 
diff --git a/xen/drivers/char/Makefile b/xen/drivers/char/Makefile
index ab2246d..9c067f9 100644
--- a/xen/drivers/char/Makefile
+++ b/xen/drivers/char/Makefile
@@ -2,4 +2,5 @@  obj-y += console.o
 obj-$(HAS_NS16550) += ns16550.o
 obj-$(HAS_PL011) += pl011.o
 obj-$(HAS_EHCI) += ehci-dbgp.o
+obj-$(CONFIG_ARM) += dt-uart.o
 obj-y += serial.o
diff --git a/xen/drivers/char/dt-uart.c b/xen/drivers/char/dt-uart.c
new file mode 100644
index 0000000..93bb0f5
--- /dev/null
+++ b/xen/drivers/char/dt-uart.c
@@ -0,0 +1,69 @@ 
+/*
+ * xen/drivers/char/dt-uart.c
+ *
+ * Generic uart retrieved via the device tree
+ *
+ * Julien Grall <julien.grall@linaro.org>
+ * Copyright (c) 2013 Linaro Limited.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <asm/device.h>
+#include <asm/early_printk.h>
+#include <asm/types.h>
+#include <xen/console.h>
+#include <xen/device_tree.h>
+#include <xen/serial.h>
+
+/*
+ * Configure UART port with a string:
+ * alias,options
+ *
+ * @alias: alias used in the device tree for the UART
+ * @options: UART speficic options (see in each UART driver)
+ */
+static char __initdata opt_dtuart[30] = "";
+string_param("dtuart", opt_dtuart);
+
+void __init dt_uart_init(void)
+{
+    struct dt_device_node *dev;
+    int ret;
+    const char *devalias = opt_dtuart;
+    char *options;
+
+    if ( !console_has("dtuart") || !strcmp(opt_dtuart, "") )
+    {
+        early_printk("No console\n");
+        return;
+    }
+
+    options = strchr(opt_dtuart, ',');
+    if ( options != NULL )
+        *(options++) = '\0';
+    else
+        options = "";
+
+    early_printk("Looking for UART console %s\n", devalias);
+    dev = dt_find_node_by_alias(devalias);
+
+    if ( !dev )
+    {
+        early_printk("Unable to find device \"%s\"\n", devalias);
+        return;
+    }
+
+    ret = device_init(dev, DEVICE_SERIAL, options);
+
+    if ( ret )
+        early_printk("Unable to initialize serial: %d\n", ret);
+}
diff --git a/xen/drivers/char/serial.c b/xen/drivers/char/serial.c
index 0ae7e4d..e1c3f47 100644
--- a/xen/drivers/char/serial.c
+++ b/xen/drivers/char/serial.c
@@ -271,6 +271,12 @@  int __init serial_parse_handle(char *conf)
         goto common;
     }
 
+    if ( !strncmp(conf, "dtuart", 5) )
+    {
+        handle = SERHND_DTUART;
+        goto common;
+    }
+
     if ( strncmp(conf, "com", 3) )
         goto fail;
 
diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
index 98a3a43..8ed72f5 100644
--- a/xen/include/asm-arm/config.h
+++ b/xen/include/asm-arm/config.h
@@ -39,7 +39,7 @@ 
 
 #define CONFIG_VIDEO 1
 
-#define OPT_CONSOLE_STR "com1"
+#define OPT_CONSOLE_STR "dtuart"
 
 #ifdef MAX_PHYS_CPUS
 #define NR_CPUS MAX_PHYS_CPUS
diff --git a/xen/include/xen/serial.h b/xen/include/xen/serial.h
index 5de5171..8af3bc4 100644
--- a/xen/include/xen/serial.h
+++ b/xen/include/xen/serial.h
@@ -9,6 +9,7 @@ 
 #ifndef __XEN_SERIAL_H__
 #define __XEN_SERIAL_H__
 
+#include <xen/init.h>
 #include <xen/spinlock.h>
 
 struct cpu_user_regs;
@@ -76,10 +77,11 @@  struct uart_driver {
 };
 
 /* 'Serial handles' are composed from the following fields. */
-#define SERHND_IDX      (3<<0) /* COM1, COM2, or DBGP?                    */
+#define SERHND_IDX      (3<<0) /* COM1, COM2, DBGP, DTUART?               */
 # define SERHND_COM1    (0<<0)
 # define SERHND_COM2    (1<<0)
 # define SERHND_DBGP    (2<<0)
+# define SERHND_DTUART  (0<<0) /* Steal SERHND_COM1 value */
 #define SERHND_HI       (1<<2) /* Mux/demux each transferred char by MSB. */
 #define SERHND_LO       (1<<3) /* Ditto, except that the MSB is cleared.  */
 #define SERHND_COOKED   (1<<4) /* Newline/carriage-return translation?    */
@@ -156,6 +158,7 @@  void ns16550_init(int index, struct ns16550_defaults *defaults);
 void ehci_dbgp_init(void);
 
 void pl011_init(int index, unsigned long register_base_address);
+void __init dt_uart_init(void);
 
 struct physdev_dbgp_op;
 int dbgp_op(const struct physdev_dbgp_op *);