linux-toradex.git/drivers/tty/serial/msm_serial.c, branch v3.13-rc2

msm_serial: Send more than 1 character on the console w/ UARTDM

2013-08-27T23:22:59+00:00

We recently added support to send more than one character at a
time for UARTDM hardware but we didn't add the same support in
the console code path. Add support here to speed up console
messages on UARTDM hardware.

Cc: David Brown 
Signed-off-by: Stephen Boyd 
Signed-off-by: Greg Kroah-Hartman

msm_serial: Add support for non-GSBI UARTDM devices

2013-08-27T23:22:59+00:00

Not all UARTDM hardware is part of a GSBI complex. Add support
for these devices and fix a bug where we assumed uartdm meant the
hardware was part of a GSBI complex.

Cc: David Brown 
Signed-off-by: Stephen Boyd 
Signed-off-by: Greg Kroah-Hartman

msm_serial: Switch clock consumer strings and simplify code

2013-08-27T23:22:58+00:00

In downstream kernel we've standardized the clock consumer names
that MSM device drivers use. Replace the uart specific clock
names in this driver with the more standard 'core' and 'iface'
names. Also simplify the code by assuming that clk_prepare_enable
and clk_disable_unprepare() will properly check for NULL pointers
(it will because MSM uses the common clock framework).

Cc: David Brown 
Signed-off-by: Stephen Boyd 
Signed-off-by: Greg Kroah-Hartman

tty: serial: msm: drop uart_port->lock before calling tty_flip_buffer_push()

2013-08-27T23:17:34+00:00

The current driver triggers a lockdep warning for if tty_flip_buffer_push() is
called with uart_port->lock locked. This never shows up on UP kernels and comes
up only on SMP kernels.

Crash looks like this (produced with samsung.c driver):

-----
[] (unwind_backtrace+0x0/0xf8) from [] (show_stack+0x10/0x14)
[] (show_stack+0x10/0x14) from [] (dump_stack+0x6c/0xac)
[] (dump_stack+0x6c/0xac) from [] (do_raw_spin_unlock+0xc4/0xd8)
[] (do_raw_spin_unlock+0xc4/0xd8) from [] (_raw_spin_unlock_irqrestore+0xc/0)
[] (_raw_spin_unlock_irqrestore+0xc/0x38) from [] (s3c24xx_serial_rx_chars+0)
[] (s3c24xx_serial_rx_chars+0x12c/0x260) from [] (s3c64xx_serial_handle_irq+)
[] (s3c64xx_serial_handle_irq+0x48/0x60) from [] (handle_irq_event_percpu+0x)
[] (handle_irq_event_percpu+0x50/0x194) from [] (handle_irq_event+0x3c/0x5c)
[] (handle_irq_event+0x3c/0x5c) from [] (handle_fasteoi_irq+0x80/0x13c)
[] (handle_fasteoi_irq+0x80/0x13c) from [] (generic_handle_irq+0x20/0x30)
[] (generic_handle_irq+0x20/0x30) from [] (handle_IRQ+0x38/0x94)
[] (handle_IRQ+0x38/0x94) from [] (gic_handle_irq+0x34/0x68)
[] (gic_handle_irq+0x34/0x68) from [] (__irq_svc+0x40/0x70)
Exception stack(0xc04cdf70 to 0xc04cdfb8)
df60:                                     00000000 00000000 0000166e 00000000
df80: c04cc000 c050278f c050278f 00000001 c04d444c 410fc0f4 c03649b0 00000000
dfa0: 00000001 c04cdfb8 c000f758 c000f75c 60070013 ffffffff
[] (__irq_svc+0x40/0x70) from [] (arch_cpu_idle+0x28/0x30)
[] (arch_cpu_idle+0x28/0x30) from [] (cpu_startup_entry+0x5c/0x148)
[] (cpu_startup_entry+0x5c/0x148) from [] (start_kernel+0x334/0x38c)
BUG: spinlock lockup suspected on CPU#0, kworker/0:1/360
 lock: s3c24xx_serial_ports+0x1d8/0x370, .magic: dead4ead, .owner: /-1, .owner_cpu: -1
CPU: 0 PID: 360 Comm: kworker/0:1 Not tainted 3.11.0-rc6-next-20130819-00003-g75485f1 #2
Workqueue: events flush_to_ldisc
[] (unwind_backtrace+0x0/0xf8) from [] (show_stack+0x10/0x14)
[] (show_stack+0x10/0x14) from [] (dump_stack+0x6c/0xac)
[] (dump_stack+0x6c/0xac) from [] (do_raw_spin_lock+0x100/0x17c)
[] (do_raw_spin_lock+0x100/0x17c) from [] (_raw_spin_lock_irqsave+0x20/0x28)
[] (_raw_spin_lock_irqsave+0x20/0x28) from [] (uart_start+0x18/0x34)
[] (uart_start+0x18/0x34) from [] (__receive_buf+0x4b4/0x738)
[] (__receive_buf+0x4b4/0x738) from [] (n_tty_receive_buf2+0x30/0x98)
[] (n_tty_receive_buf2+0x30/0x98) from [] (flush_to_ldisc+0xec/0x138)
[] (flush_to_ldisc+0xec/0x138) from [] (process_one_work+0xfc/0x348)
[] (process_one_work+0xfc/0x348) from [] (worker_thread+0x138/0x37c)
[] (worker_thread+0x138/0x37c) from [] (kthread+0xa4/0xb0)
[] (kthread+0xa4/0xb0) from [] (ret_from_fork+0x14/0x3c)
-----

Release the port lock before calling tty_flip_buffer_push() and reacquire it
after the call.

Similar stuff was already done for few other drivers in the past, like:

commit 2389b272168ceec056ca1d8a870a97fa9c26e11a
Author: Thomas Gleixner 
Date:   Tue May 29 21:53:50 2007 +0100

    [ARM] 4417/1: Serial: Fix AMBA drivers locking

Cc: David Brown  (maintainer:ARM/QUALCOMM MSM...)
Cc: Daniel Walker  (maintainer:ARM/QUALCOMM MSM...)
Cc: Bryan Huntsman  (maintainer:ARM/QUALCOMM MSM...)
Signed-off-by: Viresh Kumar 
Signed-off-by: Greg Kroah-Hartman

serial: msm_serial: fix comparison of different types

2013-08-12T18:35:32+00:00

Fix the following sparse warning:

drivers/tty/serial/msm_serial.c:237:37: error: incompatible types in comparison expression (different type sizes)

Signed-off-by: Jingoo Han 
Signed-off-by: Greg Kroah-Hartman

msm_serial: Send more than 1 character at a time on UARTDM

2013-07-26T23:13:30+00:00

UARTDM cores have a TX fifo that can accept more than one
character per register write, but the msm_serial driver currently
only supports 1 character mode. Add support for this mode of operation
to speed up the transmit path on DM devices.

Signed-off-by: Stephen Boyd 
Acked-by: David Brown 
Signed-off-by: Greg Kroah-Hartman

msm_serial: Make baud_code detection more dynamic

2013-07-26T23:13:29+00:00

Currently msm_set_baud_rate() assumes the uart clock rate is
1.8432 MHz. This is not always true, and limits our options to
program the baud rate. Instead of assuming the rate and
hard-coding the baud_code based on it, calculate the divider that
we want and try to find the closest baud_code that matches. This
allows us to support uarts with faster clock speeds.

Signed-off-by: Stephen Boyd 
Acked-by: David Brown 
Signed-off-by: Greg Kroah-Hartman

msm_serial: Fix sparse warnings

2013-07-26T23:13:29+00:00

drivers/tty/serial/msm_serial.c:302:6: warning: symbol 'msm_set_mctrl' was
not declared. Should it be static?
drivers/tty/serial/msm_serial.c:597:17: warning: incorrect type in argument 2
(different address spaces)
drivers/tty/serial/msm_serial.c:597:17: expected void volatile [noderef] *addr
drivers/tty/serial/msm_serial.c:597:17: got unsigned int *
drivers/tty/serial/msm_serial.c:608:33: warning: incorrect type in argument 1
(different address spaces)
drivers/tty/serial/msm_serial.c:608:33: expected void volatile [noderef] *addr
drivers/tty/serial/msm_serial.c:608:33: got unsigned int *gsbi_base
drivers/tty/serial/msm_serial.c:648:37: warning: incorrect type in assignment
(different address spaces)
drivers/tty/serial/msm_serial.c:648:37: expected unsigned int *gsbi_base
drivers/tty/serial/msm_serial.c:648:37: got void [noderef] *

Mark the ioremapped memory as __iomem and use writel instead of
iowrite because we're not dealing with PCI devices. Also, mark
msm_set_mctrl() static because it isn't used outside this file.

Signed-off-by: Stephen Boyd 
Acked-by: David Brown 
Signed-off-by: Greg Kroah-Hartman

msm_serial: Fix NUL byte output on UARTDM

2013-07-26T23:13:29+00:00

UARTDM serial devices require us to wait for the entire TX fifo
to drain before we can change the contents of the NCF_TX
register. Furthermore, if we write any characters to the TX fifo
within the same clock cycle of changing the NCF_TX register the
NCF_TX register won't latch properly.

To fix these issues we should read back the NCF_TX register to
delay any TX fifo accesses by a clock cycle and we should wait
for the TX fifo to drain (instead of just waiting for the fifo to
be ready to receive more characters). Failure to do so leads to
random NUL bytes interspersed in the output.

Signed-off-by: Stephen Boyd 
Acked-by: David Brown 
Signed-off-by: Greg Kroah-Hartman

msm_serial: add missing iounmap() on error in msm_request_port()

2013-07-26T23:04:50+00:00

Add the missing iounmap() before return from msm_request_port()
in the error handling case.

Signed-off-by: Wei Yongjun 
Reviewed-by: Ivan T. Ivanov 
Signed-off-by: Greg Kroah-Hartman