linux-toradex.git/drivers/tty/serial/amba-pl011.c, branch v3.4.36 Linux kernel for Apalis and Colibri modules serial: pl011: handle corruption at high clock speeds 2012-10-07T15:32:25+00:00 Linus Walleij linus.walleij@linaro.org 2012-09-26T15:21:36+00:00 c5500c74ff1414578161b796557b382d5cbaf024 commit c5dd553b9fd069892c9e2de734f4f604e280fa7a upstream. This works around a few glitches in the ST version of the PL011 serial driver when using very high baud rates, as we do in the Ux500: 3, 3.25, 4 and 4.05 Mbps. Problem Observed/rootcause: When using high baud-rates, and the baudrate*8 is getting close to the provided clock frequency (so a division factor close to 1), when using bursts of characters (so they are abutted), then it seems as if there is not enough time to detect the beginning of the start-bit which is a timing reference for the entire character, and thus the sampling moment of character bits is moving towards the end of each bit, instead of the middle. Fix: Increase slightly the RX baud rate of the UART above the theoretical baudrate by 5%. This will definitely give more margin time to the UART_RX to correctly sample the data at the middle of the bit period. Also fix the ages old copy-paste error in the very stressed comment, it's referencing the registers used in the PL010 driver rather than the PL011 ones. Signed-off-by: Guillaume Jaunet <guillaume.jaunet@stericsson.com> Signed-off-by: Christophe Arnal <christophe.arnal@stericsson.com> Signed-off-by: Matthias Locher <matthias.locher@stericsson.com> Signed-off-by: Rajanikanth HV <rajanikanth.hv@stericsson.com> Cc: Bibek Basu <bibek.basu@stericsson.com> Cc: Par-Gunnar Hjalmdahl <par-gunnar.hjalmdahl@stericsson.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c5dd553b9fd069892c9e2de734f4f604e280fa7a upstream.

This works around a few glitches in the ST version of the PL011
serial driver when using very high baud rates, as we do in the
Ux500: 3, 3.25, 4 and 4.05 Mbps.

Problem Observed/rootcause:

When using high baud-rates, and the baudrate*8 is getting close to
the provided clock frequency (so a division factor close to 1), when
using bursts of characters (so they are abutted), then it seems as if
there is not enough time to detect the beginning of the start-bit which
is a timing reference for the entire character, and thus the sampling
moment of character bits is moving towards the end of each bit, instead
of the middle.

Fix:
Increase slightly the RX baud rate of the UART above the theoretical
baudrate by 5%. This will definitely give more margin time to the
UART_RX to correctly sample the data at the middle of the bit period.

Also fix the ages old copy-paste error in the very stressed comment,
it's referencing the registers used in the PL010 driver rather than
the PL011 ones.

Signed-off-by: Guillaume Jaunet <guillaume.jaunet@stericsson.com>
Signed-off-by: Christophe Arnal <christophe.arnal@stericsson.com>
Signed-off-by: Matthias Locher <matthias.locher@stericsson.com>
Signed-off-by: Rajanikanth HV <rajanikanth.hv@stericsson.com>
Cc: Bibek Basu <bibek.basu@stericsson.com>
Cc: Par-Gunnar Hjalmdahl <par-gunnar.hjalmdahl@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: PL011: move interrupt clearing 2012-04-06T21:04:33+00:00 Linus Walleij linus.walleij@linaro.org 2012-03-21T19:15:18+00:00 c3d8b76f61586714cdc5f219ba45592a54caaa55 Commit 360f748b204275229f8398cb2f9f53955db1503b "serial: PL011: clear pending interrupts" attempts to clear interrupts by writing to a yet-unassigned memory address. This fixes the issue. The breaking patch is marked for stable so should be carried along with the other patch. Cc: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: stable <stable@vger.kernel.org> Cc: Nicolas Pitre <nico@fluxnic.net> Reported-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Commit 360f748b204275229f8398cb2f9f53955db1503b
"serial: PL011: clear pending interrupts"
attempts to clear interrupts by writing to a
yet-unassigned memory address. This fixes the issue.

The breaking patch is marked for stable so should be
carried along with the other patch.

Cc: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: stable <stable@vger.kernel.org>
Cc: Nicolas Pitre <nico@fluxnic.net>
Reported-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2012-03-29T22:34:57+00:00 Linus Torvalds torvalds@linux-foundation.org 2012-03-29T22:34:57+00:00 ef08e78268423fc4d7fbc3e54bd9a67fc8da7cc5 Pull slave-dmaengine update from Vinod Koul: "This includes the cookie cleanup by Russell, the addition of context parameter for dmaengine APIs, more arm dmaengine driver cleanup by moving code to dmaengine, this time for imx by Javier and pl330 by Boojin along with the usual driver fixes." Fix up some fairly trivial conflicts with various other cleanups. * 'next' of git://git.infradead.org/users/vkoul/slave-dma: (67 commits) dmaengine: imx: fix the build failure on x86_64 dmaengine: i.MX: Fix merge of cookie branch. dmaengine: i.MX: Add support for interleaved transfers. dmaengine: imx-dma: use 'dev_dbg' and 'dev_warn' for messages. dmaengine: imx-dma: remove 'imx_dmav1_baseaddr' and 'dma_clk'. dmaengine: imx-dma: remove unused arg of imxdma_sg_next. dmaengine: imx-dma: remove internal structure. dmaengine: imx-dma: remove 'resbytes' field of 'internal' structure. dmaengine: imx-dma: remove 'in_use' field of 'internal' structure. dmaengine: imx-dma: remove sg member from internal structure. dmaengine: imx-dma: remove 'imxdma_setup_sg_hw' function. dmaengine: imx-dma: remove 'imxdma_config_channel_hw' function. dmaengine: imx-dma: remove 'imxdma_setup_mem2mem_hw' function. dmaengine: imx-dma: remove dma_mode member of internal structure. dmaengine: imx-dma: remove data member from internal structure. dmaengine: imx-dma: merge old dma-v1.c with imx-dma.c dmaengine: at_hdmac: add slave config operation dmaengine: add context parameter to prep_slave_sg and prep_dma_cyclic dmaengine/dma_slave: introduce inline wrappers dma: imx-sdma: Treat firmware messages as warnings instead of erros ... 
Pull slave-dmaengine update from Vinod Koul:
 "This includes the cookie cleanup by Russell, the addition of context
  parameter for dmaengine APIs, more arm dmaengine driver cleanup by
  moving code to dmaengine, this time for imx by Javier and pl330 by
  Boojin along with the usual driver fixes."

Fix up some fairly trivial conflicts with various other cleanups.

* 'next' of git://git.infradead.org/users/vkoul/slave-dma: (67 commits)
  dmaengine: imx: fix the build failure on x86_64
  dmaengine: i.MX: Fix merge of cookie branch.
  dmaengine: i.MX: Add support for interleaved transfers.
  dmaengine: imx-dma: use 'dev_dbg' and 'dev_warn' for messages.
  dmaengine: imx-dma: remove 'imx_dmav1_baseaddr' and 'dma_clk'.
  dmaengine: imx-dma: remove unused arg of imxdma_sg_next.
  dmaengine: imx-dma: remove internal structure.
  dmaengine: imx-dma: remove 'resbytes' field of 'internal' structure.
  dmaengine: imx-dma: remove 'in_use' field of 'internal' structure.
  dmaengine: imx-dma: remove sg member from internal structure.
  dmaengine: imx-dma: remove 'imxdma_setup_sg_hw' function.
  dmaengine: imx-dma: remove 'imxdma_config_channel_hw' function.
  dmaengine: imx-dma: remove 'imxdma_setup_mem2mem_hw' function.
  dmaengine: imx-dma: remove dma_mode member of internal structure.
  dmaengine: imx-dma: remove data member from internal structure.
  dmaengine: imx-dma: merge old dma-v1.c with imx-dma.c
  dmaengine: at_hdmac: add slave config operation
  dmaengine: add context parameter to prep_slave_sg and prep_dma_cyclic
  dmaengine/dma_slave: introduce inline wrappers
  dma: imx-sdma: Treat firmware messages as warnings instead of erros
  ...
dmaengine/dma_slave: introduce inline wrappers 2012-03-21T13:50:22+00:00 Alexandre Bounine alexandre.bounine@idt.com 2012-03-08T21:11:18+00:00 16052827d98fbc13c31ebad560af4bd53e2b4dd5 Add inline wrappers for device_prep_slave_sg() and device_prep_dma_cyclic() interfaces to hide new parameter from current users of affected interfaces. Convert current users to use new wrappers instead of direct calls. Suggested by Russell King [https://lkml.org/lkml/2012/2/3/269]. Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com> Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com> 
Add inline wrappers for device_prep_slave_sg() and device_prep_dma_cyclic()
interfaces to hide new parameter from current users of affected interfaces.
Convert current users to use new wrappers instead of direct calls.
Suggested by Russell King [https://lkml.org/lkml/2012/2/3/269].

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
serial: PL011: clear pending interrupts 2012-03-14T19:27:39+00:00 Linus Walleij linus.walleij@linaro.org 2012-03-13T12:27:23+00:00 9b96fbacda34079dea0638ee1e92c56286f6114a Chanho Min reported that when the boot loader transfers control to the kernel, there may be pending interrupts causing the UART to lock up in an eternal loop trying to pick tokens from the FIFO (since the RX interrupt flag indicates there are tokens) while in practice there are no tokens - in fact there is only a pending IRQ flag. This patch address the issue with a combination of two patches suggested by Russell King that clears and mask all interrupts at probe() and clears any pending error and RX interrupts at port startup time. We suspect the spurious interrupts are a side-effect of switching the UART from FIFO to non-FIFO mode. Cc: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com> Reported-by: Chanho Min <chanho0207@gmail.com> Suggested-by: Russell King <linux@arm.linux.org.uk> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Jong-Sung Kim <neidhard.kim@lge.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Chanho Min reported that when the boot loader transfers
control to the kernel, there may be pending interrupts
causing the UART to lock up in an eternal loop trying to
pick tokens from the FIFO (since the RX interrupt flag
indicates there are tokens) while in practice there are
no tokens - in fact there is only a pending IRQ flag.

This patch address the issue with a combination of two
patches suggested by Russell King that clears and mask
all interrupts at probe() and clears any pending error
and RX interrupts at port startup time.

We suspect the spurious interrupts are a side-effect of
switching the UART from FIFO to non-FIFO mode.

Cc: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Reported-by: Chanho Min <chanho0207@gmail.com>
Suggested-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Jong-Sung Kim <neidhard.kim@lge.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
amba-pl011​/dma: Add check for the residue in DMA callback 2012-02-24T21:50:47+00:00 Chanho Min chanho0207@gmail.com 2012-02-20T01:24:40+00:00 6dc01aa65306fe46b7ba38db51fad4ed81c23d00 In DMA-operated uart, I found that rx data can be taken by the UART interrupts during the DMA irq handler. pl011_int is occurred just before it goes inside spin_lock_irq. When it returns to the callback, DMA buffer already has been flushed. Then, pl011_dma_rx_chars gets invalid data. So I add check for the residue as the patch bellow. Signed-off-by: Chanho Min <chanho.min@lge.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
In DMA-operated uart, I found that rx data can be taken by the UART
interrupts during the DMA irq handler. pl011_int is occurred just
before it goes inside spin_lock_irq. When it returns to the callback,
DMA buffer already has been flushed. Then, pl011_dma_rx_chars gets
invalid data. So I add check for the residue as the patch bellow.

Signed-off-by: Chanho Min <chanho.min@lge.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
dmaengine: Pass dma_slave_config .device_fc = NULL for all existing users 2012-02-22T12:45:37+00:00 Viresh Kumar viresh.kumar@st.com 2012-02-01T10:42:19+00:00 258aea76f552cc755da92e7e823abbb85e021514 .device_fc is added in struct dma_slave_config recently. All user drivers, which want DMA to be the flow controller must pass this field as false. As earlier driver don't look to use this feature, mark it false for now. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com> 
.device_fc is added in struct dma_slave_config recently. All user drivers, which
want DMA to be the flow controller must pass this field as false. As earlier
driver don't look to use this feature, mark it false for now.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
serial: amba-pl011: lock console writes against interrupts 2012-01-25T00:09:55+00:00 Rabin Vincent rabin.vincent@stericsson.com 2012-01-17T10:52:28+00:00 ef605fdb33883d687cff5ba75095a91b313b4966 Protect against pl011_console_write() and the interrupt for the console UART running concurrently on different CPUs. Otherwise the console_write could spin for a long time waiting for the UART to become not busy, while the other CPU continuously services UART interrupts and keeps the UART busy. The checks for sysrq and oops_in_progress are taken from 8250.c. Cc: stable <stable@vger.kernel.org> Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com> Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com> Reviewed-by: Bibek Basu <bibek.basu@stericsson.com> Reviewed-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
Protect against pl011_console_write() and the interrupt for
the console UART running concurrently on different CPUs.

Otherwise the console_write could spin for a long time
waiting for the UART to become not busy, while the other
CPU continuously services UART interrupts and keeps the
UART busy.

The checks for sysrq and oops_in_progress are taken
from 8250.c.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Reviewed-by: Bibek Basu <bibek.basu@stericsson.com>
Reviewed-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
amba-pl011: do not disable RTS during shutdown 2012-01-25T00:09:55+00:00 Shreshtha Kumar Sahu shreshthakumar.sahu@stericsson.com 2012-01-18T10:23:59+00:00 d8d8ffa477831b713ddfa2ad4d0ca545f3b567e5 In present driver, shutdown clears RTS and DTR in CR register. But the documentation "Documentation/serial/driver" suggests not to disable RTS and DTR in shutdown(). Also RTS and DTR is preserved between shutdown and startup calls, i.e. these are restored in startup if they were enabled while doing shutdown. So that if RTS and DTR are set using pl011_set_mctrl then it should continue even after shutdown->startup sequence. For throttling/unthrottling user should call pl011_set_mctrl. Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
In present driver, shutdown clears RTS and DTR in CR register. But the
documentation "Documentation/serial/driver" suggests not to disable
RTS and DTR in shutdown(). Also RTS and DTR is preserved between shutdown
and startup calls, i.e. these are restored in startup if they were enabled
while doing shutdown. So that if RTS and DTR are set using pl011_set_mctrl
then it should continue even after shutdown->startup sequence.
For throttling/unthrottling user should call pl011_set_mctrl.

Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2012-01-18T02:40:24+00:00 Linus Torvalds torvalds@linux-foundation.org 2012-01-18T02:40:24+00:00 57f2685c16fa8e0cb86e4bc7c8ac33bfed943819 * 'next' of git://git.infradead.org/users/vkoul/slave-dma: (53 commits) ARM: mach-shmobile: specify CHCLR registers on SH7372 dma: shdma: fix runtime PM: clear channel buffers on reset dma/imx-sdma: save irq flags when use spin_lock in sdma_tx_submit dmaengine/ste_dma40: clear LNK on channel startup dmaengine: intel_mid_dma: remove legacy pm interface ASoC: mxs: correct 'direction' of device_prep_dma_cyclic dmaengine: intel_mid_dma: error path fix dmaengine: intel_mid_dma: locking and freeing fixes mtd: gpmi-nand: move to dma_transfer_direction mtd: fix compile error for gpmi-nand mmc: mxs-mmc: fix the dma_transfer_direction migration dmaengine: add DMA_TRANS_NONE to dma_transfer_direction dma: mxs-dma: Don't use CLKGATE bits in CTRL0 to disable DMA channels dma: mxs-dma: make mxs_dma_prep_slave_sg() multi user safe dma: mxs-dma: Always leave mxs_dma_init() with the clock disabled. dma: mxs-dma: fix a typo in comment DMA: PL330: Remove pm_runtime_xxx calls from pl330 probe/remove video i.MX IPU: Fix display connections i.MX IPU DMA: Fix wrong burstsize settings dmaengine/ste_dma40: allow fixed physical channel ... Fix up conflicts in drivers/dma/{Kconfig,mxs-dma.c,pl330.c} The conflicts looked pretty trivial, but I'll ask people to verify them. 
* 'next' of git://git.infradead.org/users/vkoul/slave-dma: (53 commits)
  ARM: mach-shmobile: specify CHCLR registers on SH7372
  dma: shdma: fix runtime PM: clear channel buffers on reset
  dma/imx-sdma: save irq flags when use spin_lock in sdma_tx_submit
  dmaengine/ste_dma40: clear LNK on channel startup
  dmaengine: intel_mid_dma: remove legacy pm interface
  ASoC: mxs: correct 'direction' of device_prep_dma_cyclic
  dmaengine: intel_mid_dma: error path fix
  dmaengine: intel_mid_dma: locking and freeing fixes
  mtd: gpmi-nand: move to dma_transfer_direction
  mtd: fix compile error for gpmi-nand
  mmc: mxs-mmc: fix the dma_transfer_direction migration
  dmaengine: add DMA_TRANS_NONE to dma_transfer_direction
  dma: mxs-dma: Don't use CLKGATE bits in CTRL0 to disable DMA channels
  dma: mxs-dma: make mxs_dma_prep_slave_sg() multi user safe
  dma: mxs-dma: Always leave mxs_dma_init() with the clock disabled.
  dma: mxs-dma: fix a typo in comment
  DMA: PL330: Remove pm_runtime_xxx calls from pl330 probe/remove
  video i.MX IPU: Fix display connections
  i.MX IPU DMA: Fix wrong burstsize settings
  dmaengine/ste_dma40: allow fixed physical channel
  ...

Fix up conflicts in drivers/dma/{Kconfig,mxs-dma.c,pl330.c}

The conflicts looked pretty trivial, but I'll ask people to verify them.