U-Boot serial code already handles -EAGAIN value from getc and putc
callbacks. So change drivers code to return -EAGAIN when HW is busy instead
of doing its own busy loop and waiting until HW is ready.
Signed-off-by: Pali Rohár <pali@kernel.org>
CONFIG_VAL(DEBUG_UART_BASE) expands to CONFIG_DEBUG_UART_BASE or
CONFIG_SPL_DEBUG_UART_BASE or CONFIG_TPL_DEBUG_UART_BASE and allows boards
to set different values for SPL, TPL and U-Boot Proper.
For ns16550 driver this support is there since commit d293759d55
("serial: ns16550: Add support for SPL_DEBUG_UART_BASE").
Signed-off-by: Pali Rohár <pali@kernel.org>
There is no maintainer entry for serial_mvebu_a3700.c. Add entry with Pali
and Stefan as maintainers.
Signed-off-by: Pali Rohár <pali@kernel.org>
Acked-by: Stefan Roese <sr@denx.de>
Reviewed-by: Stefan Roese <sr@denx.de>
Sometimes UART stops transmitting characters after UART clock is changed
back to XTAL. In this state UART fifo is always full. Kernel during early
boot wants to print output on UART and is waiting for non-empty UART fifo.
Which leads to CPU hangup without any (debug) output on UART.
Marvell Armada 3700 Functional Specifications says that for programming
fractional divisor registers it is required to disable UART, enable
loopback mode, reset fifos, program registers, disable loopback mode,
release reset of fifos and enable UART.
But these steps do not fix above mentioned issue that UART hangup. Also
gating UART clock does not help. And even resetting UART state machines do
not help.
Experiments showed that UART fifo is unblocked after board is being reset
(during board reset UART HW transmit UART fifo even CPU is not executing
kernel/bootloader anymore).
And another experiments showed that same workaround can be achieved also
by external reset of UART HW (without need to reset board).
So do not implement any of "Marvell recommended" steps from Functional
Specifications as they do not work. And rather prior changing parent clock
back to XTAL, do external reset of UART HW. This operation also resets all
UART registers, so basically it also sets UART clock to default, which is
XTAL. It is unknown why UART hangups and enters such broken state.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
Static inline function _debug_uart_init() should avoid calling external
(non-inline) functions. Therefore do not call get_ref_clk() in
_debug_uart_init() and reimplement its functionality without external
function calls.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
CONFIG_BAUDRATE should be used for setting the baudrate for the early debug
UART. This replaces current hardcoded 115200 value.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behun <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
Unfortunately the UART driver in current Linux for Armada 3700 expects
UART's parent clock to be XTAL and calculats baudrate divisor according
to XTAL clock. Therefore we must switch back to XTAL clock before
booting kernel.
Implement .remove method for this driver with DM_FLAG_OS_PREPARE flag
set.
If current baudrate is unsuitable for XTAL clock then we do not change
anything. This can only happen if the user either configured unsupported
settings or knows what they are doing and has kernel patches which allow
usage of non-XTAL parent clock.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
Using TBG clock as parent clock for UART allows us using higher
baudrates than 230400.
Turris MOX with external FT232RL USB-UART works fine up to 3 MBaud
(which is maximum for this USB-UART controller), while EspressoBIN with
integrated pl2303 USB-UART also works fine up to 6 MBaud.
Slower baudrates with TBG as a parent clock can be achieved by
increasing TBG dividers and oversampling divider. When using the slowest
TBG clock, minimal working baudrate is 300.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
UART parent clock is by default the platform's xtal clock, which is
25 MHz.
The value defined in the driver, though, is 25.8048 MHz. This is a hack
for the suboptimal divisor calculation
Divisor = UART clock / (16 * baudrate)
which does not use rounding division, resulting in a suboptimal value
for divisor if the correct parent clock rate was used.
Change the code for divisor calculation to round to closest value, i.e.
Divisor = Round(UART clock / (16 * baudrate))
and change the parent clock rate value to that returned by
get_ref_clk().
This makes A3720 UART stable at standard UART baudrates between 1800 and
230400.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
To check if some output characters are waiting either in Transmitter
Holding Register or Transmitter Shift Register we need to look at
TX_EMPTY bit of UART Status Register.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
This name is far too long. Rename it to remove the 'data' bits. This makes
it consistent with the platdata->plat rename.
Signed-off-by: Simon Glass <sjg@chromium.org>
We use 'priv' for private data but often use 'platdata' for platform data.
We can't really use 'pdata' since that is ambiguous (it could mean private
or platform data).
Rename some of the latter variables to end with 'plat' for consistency.
Signed-off-by: Simon Glass <sjg@chromium.org>
This construct is quite long-winded. In earlier days it made some sense
since auto-allocation was a strange concept. But with driver model now
used pretty universally, we can shorten this to 'auto'. This reduces
verbosity and makes it easier to read.
Coincidentally it also ensures that every declaration is on one line,
thus making dtoc's job easier.
Signed-off-by: Simon Glass <sjg@chromium.org>
When you enable CONFIG_OF_LIVE, you will end up with a lot of
conversions.
To help this tedious work, this commit converts devfdt_get_addr_ptr()
to dev_read_addr_ptr() by coccinelle. I also removed redundant casts
because dev_read_addr_ptr() returns an opaque pointer.
To generate this commit, I ran the following semantic patch
excluding include/dm/.
<smpl>
@@
type T;
expression dev;
@@
-(T *)devfdt_get_addr_ptr(dev)
+dev_read_addr_ptr(dev)
@@
expression dev;
@@
-devfdt_get_addr_ptr(dev)
+dev_read_addr_ptr(dev)
</smpl>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
When a driver declares DM_FLAG_PRE_RELOC flag, it wishes to be
bound before relocation. However due to a bug in the DM core,
the flag only takes effect when devices are statically declared
via U_BOOT_DEVICE(). This bug has been fixed recently by commit
"dm: core: Respect drivers with the DM_FLAG_PRE_RELOC flag in
lists_bind_fdt()", but with the fix, it has a side effect that
all existing drivers that declared DM_FLAG_PRE_RELOC flag will
be bound before relocation now. This may expose potential boot
failure on some boards due to insufficient memory during the
pre-relocation stage.
To mitigate this potential impact, the following changes are
implemented:
- Remove DM_FLAG_PRE_RELOC flag in the driver, if the driver
only supports configuration from device tree (OF_CONTROL)
- Keep DM_FLAG_PRE_RELOC flag in the driver only if the device
is statically declared via U_BOOT_DEVICE()
- Surround DM_FLAG_PRE_RELOC flag with OF_CONTROL check, for
drivers that support both statically declared devices and
configuration from device tree
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from. So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry. Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.
In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.
This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents. There's also a few places where I found we did not have a tag
and have introduced one.
Signed-off-by: Tom Rini <trini@konsulko.com>
These support the flat device tree. We want to use the dev_read_..()
prefix for functions that support both flat tree and live tree. So rename
the existing functions to avoid confusion.
In the end we will have:
1. dev_read_addr...() - works on devices, supports flat/live tree
2. devfdt_get_addr...() - current functions, flat tree only
3. of_get_address() etc. - new functions, live tree only
All drivers will be written to use 1. That function will in turn call
either 2 or 3 depending on whether the flat or live tree is in use.
Note this involves changing some dead code - the imx_lpi2c.c file.
Signed-off-by: Simon Glass <sjg@chromium.org>
The Armada 3700's UART is a simple serial port. It has a 32 bytes
Tx FIFO and a 64 bytes Rx FIFO integrated. This patch adds support
for this UART including the DEBUG UART functions for very early
debug output.
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Nadav Haklai <nadavh@marvell.com>
Cc: Kostya Porotchkin <kostap@marvell.com>
Cc: Wilson Ding <dingwei@marvell.com>
Cc: Victor Gu <xigu@marvell.com>
Cc: Hua Jing <jinghua@marvell.com>
Cc: Terry Zhou <bjzhou@marvell.com>
Cc: Hanna Hawa <hannah@marvell.com>
Cc: Haim Boot <hayim@marvell.com>
