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From: bigeasy@linutronix.de (Sebastian Andrzej Siewior)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 01/18] tty: serial: 8250_core: provide a function to export uart_8250_port
Date: Fri,  5 Sep 2014 21:02:36 +0200
Message-ID: <1409943773-7874-2-git-send-email-bigeasy@linutronix.de> (raw)
In-Reply-To: <1409943773-7874-1-git-send-email-bigeasy@linutronix.de>

There is no way to access a struct uart_8250_port for a specific
line. This is only required outside of the 8250/uart callbacks like for
devices' suspend & remove callbacks. For those the 8250-core provides a
wrapper like serial8250_unregister_port() which passes the struct
to the proper function based on the line argument.

For run time suspend I need access to this struct not only to make
serial_out() work but also to properly restore up->ier and up->mcr.

Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/tty/serial/8250/8250.h      |  2 ++
 drivers/tty/serial/8250/8250_core.c | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 1b08c918cd51..85bfec58d77c 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -112,6 +112,8 @@ static inline void serial_dl_write(struct uart_8250_port *up, int value)
 	up->dl_write(up, value);
 }
 
+struct uart_8250_port *serial8250_get_port(int line);
+
 #if defined(__alpha__) && !defined(CONFIG_PCI)
 /*
  * Digital did something really horribly wrong with the OUT1 and OUT2
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 1d42dba6121d..e2ad13a9aea4 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2880,6 +2880,24 @@ static struct uart_ops serial8250_pops = {
 
 static struct uart_8250_port serial8250_ports[UART_NR];
 
+/**
+ * serial8250_get_port - retrieve struct uart_8250_port
+ * @line: serial line number
+ *
+ * This function retrieves struct uart_8250_port for the specific line.
+ * This struct *must* *not* be used to perform a 8250 or serial core operation
+ * which is not accessible otherwise. Its only purpose is to make the struct
+ * accessible to the runtime-pm callbacks for context suspend/restore.
+ * The lock assumption made here is none because runtime-pm suspend/resume
+ * callbacks should not be invoked if there is any operation performed on the
+ * port.
+ */
+struct uart_8250_port *serial8250_get_port(int line)
+{
+	return &serial8250_ports[line];
+}
+EXPORT_SYMBOL_GPL(serial8250_get_port);
+
 static void (*serial8250_isa_config)(int port, struct uart_port *up,
 	unsigned short *capabilities);
 
-- 
2.1.0

  reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-05 19:02 [PATCH v8 00/18] 8250-core based serial driver for OMAP + DMA Sebastian Andrzej Siewior
2014-09-05 19:02 ` Sebastian Andrzej Siewior [this message]
2014-09-05 19:02 ` [PATCH 02/18] tty: serial: 8250_core: allow to overwrite & export serial8250_startup() Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 03/18] tty: serial: 8250_core: allow to set ->throttle / ->unthrottle callbacks Sebastian Andrzej Siewior
2014-09-08 23:33   ` Greg Kroah-Hartman
2014-09-09  0:41     ` Tony Lindgren
2014-09-05 19:02 ` [PATCH 04/18] tty: serial: 8250_core: add run time pm Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 05/18] tty: serial: 8250_core: read only RX if there is something in the FIFO Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 06/18] tty: serial: 8250_core: user the ->line argument as a hint in serial8250_find_match_or_unused() Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 07/18] tty: serial: 8250_core: remove UART_IER_RDI in serial8250_stop_rx() Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 08/18] tty: serial: Add 8250-core based omap driver Sebastian Andrzej Siewior
2014-09-08 16:39   ` Tony Lindgren
2014-09-05 19:02 ` [PATCH 09/18] tty: serial: 8250_dma: handle error on TX submit Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 10/18] tty: serial: 8250_dma: enqueue RX dma again on completion Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 11/18] tty: serial: 8250_dma: Add a TX trigger workaround for AM33xx Sebastian Andrzej Siewior
2014-09-08 16:41   ` Tony Lindgren
2014-09-08 16:45     ` Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 12/18] tty: serial: 8250_dma: optimize the xmit path due to UART_BUG_DMA_TX Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 13/18] tty: serial: 8250_dma: keep own book keeping about RX transfers Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 14/18] tty: serial: 8250_dma: handle the when UART response while DMA remains idle Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 15/18] tty: serial: 8250_dma: add pm runtime Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 16/18] arm: dts: am33xx: add DMA properties for UART Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 17/18] arm: dts: dra7: " Sebastian Andrzej Siewior
2014-09-05 19:02 ` [PATCH 18/18] tty: serial: 8250: omap: add dma support Sebastian Andrzej Siewior
2014-09-08 14:46 ` [PATCH v8 00/18] 8250-core based serial driver for OMAP + DMA Frans Klaver
2014-09-08 15:15   ` Sebastian Andrzej Siewior
2014-09-08 16:33     ` Sebastian Andrzej Siewior
2014-09-08 18:25       ` Frans Klaver
2014-09-08 18:33     ` Frans Klaver
2014-09-09 19:41       ` Sebastian Andrzej Siewior
2014-09-10 14:15         ` Frans Klaver
2014-09-10 16:56           ` Sebastian Andrzej Siewior
2014-09-08 17:40 ` Tony Lindgren
2014-09-08 17:55   ` Tony Lindgren
2014-09-09  7:33     ` Sebastian Andrzej Siewior

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