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2019-08-04serial: sh-sci: Fix TX DMA buffer flushing and workqueue racesGeert Uytterhoeven1-7/+15
[ Upstream commit 8493eab02608b0e82f67b892aa72882e510c31d0 ] When uart_flush_buffer() is called, the .flush_buffer() callback zeroes the tx_dma_len field. This may race with the work queue function handling transmit DMA requests: 1. If the buffer is flushed before the first DMA API call, dmaengine_prep_slave_single() may be called with a zero length, causing the DMA request to never complete, leading to messages like: rcar-dmac e7300000.dma-controller: Channel Address Error happen and, with debug enabled: sh-sci e6e88000.serial: sci_dma_tx_work_fn: ffff800639b55000: 0...0, cookie 126 and DMA timeouts. 2. If the buffer is flushed after the first DMA API call, but before the second, dma_sync_single_for_device() may be called with a zero length, causing the transmit data not to be flushed to RAM, and leading to stale data being output. Fix this by: 1. Letting sci_dma_tx_work_fn() return immediately if the transmit buffer is empty, 2. Extending the critical section to cover all DMA preparational work, so tx_dma_len stays consistent for all of it, 3. Using local copies of circ_buf.head and circ_buf.tail, to make sure they match the actual operation above. Reported-by: Eugeniu Rosca <erosca@de.adit-jv.com> Suggested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com> Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com> Link: https://lore.kernel.org/r/20190624123540.20629-2-geert+renesas@glider.be Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-04-03serial: sh-sci: Fix setting SCSCR_TIE while transferring dataHoan Nguyen An1-11/+1
commit 93bcefd4c6bad4c69dbc4edcd3fbf774b24d930d upstream. We disable transmission interrupt (clear SCSCR_TIE) after all data has been transmitted (if uart_circ_empty(xmit)). While transmitting, if the data is still in the tty buffer, re-enable the SCSCR_TIE bit, which was done at sci_start_tx(). This is unnecessary processing, wasting CPU operation if the data transmission length is large. And further, transmit end, FIFO empty bits disabling have also been performed in the step above. Signed-off-by: Hoan Nguyen An <na-hoan@jinso.co.jp> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-03serial: sh-sci: Use spin_{try}lock_irqsave instead of open coding versionDaniel Wagner1-5/+3
commit 8afb1d2c12163f77777f84616a8e9444d0050ebe upstream. Commit 40f70c03e33a ("serial: sh-sci: add locking to console write function to avoid SMP lockup") copied the strategy to avoid locking problems in conjuncture with the console from the UART8250 driver. Instead using directly spin_{try}lock_irqsave(), local_irq_save() followed by spin_{try}lock() was used. While this is correct on mainline, for -rt it is a problem. spin_{try}lock() will check if it is running in a valid context. Since the local_irq_save() has already been executed, the context has changed and spin_{try}lock() will complain. The reason why spin_{try}lock() complains is that on -rt the spin locks are turned into mutexes and therefore can sleep. Sleeping with interrupts disabled is not valid. BUG: sleeping function called from invalid context at /home/wagi/work/rt/v4.4-cip-rt/kernel/locking/rtmutex.c:995 in_atomic(): 0, irqs_disabled(): 128, pid: 778, name: irq/76-eth0 CPU: 0 PID: 778 Comm: irq/76-eth0 Not tainted 4.4.126-test-cip22-rt14-00403-gcd03665c8318 #12 Hardware name: Generic RZ/G1 (Flattened Device Tree) Backtrace: [<c00140a0>] (dump_backtrace) from [<c001424c>] (show_stack+0x18/0x1c) r7:c06b01f0 r6:60010193 r5:00000000 r4:c06b01f0 [<c0014234>] (show_stack) from [<c01d3c94>] (dump_stack+0x78/0x94) [<c01d3c1c>] (dump_stack) from [<c004c134>] (___might_sleep+0x134/0x194) r7:60010113 r6:c06d3559 r5:00000000 r4:ffffe000 [<c004c000>] (___might_sleep) from [<c04ded60>] (rt_spin_lock+0x20/0x74) r5:c06f4d60 r4:c06f4d60 [<c04ded40>] (rt_spin_lock) from [<c02577e4>] (serial_console_write+0x100/0x118) r5:c06f4d60 r4:c06f4d60 [<c02576e4>] (serial_console_write) from [<c0061060>] (call_console_drivers.constprop.15+0x10c/0x124) r10:c06d2894 r9:c04e18b0 r8:00000028 r7:00000000 r6:c06d3559 r5:c06d2798 r4:c06b9914 r3:c02576e4 [<c0060f54>] (call_console_drivers.constprop.15) from [<c0062984>] (console_unlock+0x32c/0x430) r10:c06d30d8 r9:00000028 r8:c06dd518 r7:00000005 r6:00000000 r5:c06d2798 r4:c06d2798 r3:00000028 [<c0062658>] (console_unlock) from [<c0062e1c>] (vprintk_emit+0x394/0x4f0) r10:c06d2798 r9:c06d30ee r8:00000006 r7:00000005 r6:c06a78fc r5:00000027 r4:00000003 [<c0062a88>] (vprintk_emit) from [<c0062fa0>] (vprintk+0x28/0x30) r10:c060bd46 r9:00001000 r8:c06b9a90 r7:c06b9a90 r6:c06b994c r5:c06b9a3c r4:c0062fa8 [<c0062f78>] (vprintk) from [<c0062fb8>] (vprintk_default+0x10/0x14) [<c0062fa8>] (vprintk_default) from [<c009cd30>] (printk+0x78/0x84) [<c009ccbc>] (printk) from [<c025afdc>] (credit_entropy_bits+0x17c/0x2cc) r3:00000001 r2:decade60 r1:c061a5ee r0:c061a523 r4:00000006 [<c025ae60>] (credit_entropy_bits) from [<c025bf74>] (add_interrupt_randomness+0x160/0x178) r10:466e7196 r9:1f536000 r8:fffeef74 r7:00000000 r6:c06b9a60 r5:c06b9a3c r4:dfbcf680 [<c025be14>] (add_interrupt_randomness) from [<c006536c>] (irq_thread+0x1e8/0x248) r10:c006537c r9:c06cdf21 r8:c0064fcc r7:df791c24 r6:df791c00 r5:ffffe000 r4:df525180 [<c0065184>] (irq_thread) from [<c003fba4>] (kthread+0x108/0x11c) r10:00000000 r9:00000000 r8:c0065184 r7:df791c00 r6:00000000 r5:df791d00 r4:decac000 [<c003fa9c>] (kthread) from [<c00101b8>] (ret_from_fork+0x14/0x3c) r8:00000000 r7:00000000 r6:00000000 r5:c003fa9c r4:df791d00 Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Daniel Wagner <daniel.wagner@siemens.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> [dw: Backported to 4.4.] Signed-off-by: Daniel Wagner <daniel.wagner@siemens.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-13serial: sh-sci: Fix race condition causing garbage during shutdownGeert Uytterhoeven1-2/+14
[ Upstream commit 1cf4a7efdc71cab84c42cfea7200608711ea954f ] If DMA is enabled and used, a burst of old data may be seen on the serial console during "poweroff" or "reboot". uart_flush_buffer() clears the circular buffer, but sci_port.tx_dma_len is not reset. This leads to a circular buffer overflow, dumping (UART_XMIT_SIZE - sci_port.tx_dma_len) bytes. To fix this, add a .flush_buffer() callback that resets sci_port.tx_dma_len. Inspired by commit 31ca2c63fdc0aee7 ("tty/serial: atmel: fix race condition (TX+DMA)"). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-18serial: sh-sci: prevent lockup on full TTY buffersUlrich Hecht1-0/+2
commit 7842055bfce4bf0170d0f61df8b2add8399697be upstream. When the TTY buffers fill up to the configured maximum, a system lockup occurs: [ 598.820128] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 598.825796] 0-...!: (1 GPs behind) idle=5a6/2/0 softirq=1974/1974 fqs=1 [ 598.832577] (detected by 3, t=62517 jiffies, g=296, c=295, q=126) [ 598.838755] Task dump for CPU 0: [ 598.841977] swapper/0 R running task 0 0 0 0x00000022 [ 598.849023] Call trace: [ 598.851476] __switch_to+0x98/0xb0 [ 598.854870] (null) This can be prevented by doing a dummy read of the RX data register. This issue affects both HSCIF and SCIF ports. Reported for R-Car H3 ES2.0; reproduced and fixed on H3 ES1.1. Probably affects other R-Car platforms as well. Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: stable <stable@vger.kernel.org> Tested-by: Nguyen Viet Dung <dung.nguyen.aj@renesas.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-15serial: sh-sci: Fix register offsets for the IRDA serial portLaurent Pinchart1-9/+8
[ Upstream commit a752ba18af8285e3eeda572f40dddaebff0c3621 ] Even though most of its registers are 8-bit wide, the IRDA has two 16-bit registers that make it a 16-bit peripheral and not a 8-bit peripheral with addresses shifted by one. Fix the registers offset in the driver and the platform data regshift value. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-14serial: sh-sci: Fix panic when serial console and DMA are enabledTakatoshi Akiyama1-4/+6
commit 3c9101766b502a0163d1d437fada5801cf616be2 upstream. This patch fixes an issue that kernel panic happens when DMA is enabled and we press enter key while the kernel booting on the serial console. * An interrupt may occur after sci_request_irq(). * DMA transfer area is initialized by setup_timer() in sci_request_dma() and used in interrupt. If an interrupt occurred between sci_request_irq() and setup_timer() in sci_request_dma(), DMA transfer area has not been initialized yet. So, this patch changes the order of sci_request_irq() and sci_request_dma(). Fixes: 73a19e4c0301 ("serial: sh-sci: Add DMA support.") Signed-off-by: Takatoshi Akiyama <takatoshi.akiyama.kj@ps.hitachi-solutions.com> [Shimoda changes the commit log] Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-05serial: sh-sci: Remove cpufreq notifier to fix crash/deadlockGeert Uytterhoeven1-39/+0
commit ff1cab374ad98f4b9f408525ca9c08992b4ed784 upstream. The BSP team noticed that there is spin/mutex lock issue on sh-sci when CPUFREQ is used. The issue is that the notifier function may call mutex_lock() while the spinlock is held, which can lead to a BUG(). This may happen if CPUFREQ is changed while another CPU calls clk_get_rate(). Taking the spinlock was added to the notifier function in commit e552de2413edad1a ("sh-sci: add platform device private data"), to protect the list of serial ports against modification during traversal. At that time the Common Clock Framework didn't exist yet, and clk_get_rate() just returned clk->rate without taking a mutex. Note that since commit d535a2305facf9b4 ("serial: sh-sci: Require a device per port mapping."), there's no longer a list of serial ports to traverse, and taking the spinlock became superfluous. To fix the issue, just remove the cpufreq notifier: 1. The notifier doesn't work correctly: all it does is update stored clock rates; it does not update the divider in the hardware. The divider will only be updated when calling sci_set_termios(). I believe this was broken back in 2004, when the old drivers/char/sh-sci.c driver (where the notifier did update the divider) was replaced by drivers/serial/sh-sci.c (where the notifier just updated port->uartclk). Cfr. full-history-linux commits 6f8deaef2e9675d9 ("[PATCH] sh: port sh-sci driver to the new API") and 3f73fe878dc9210a ("[PATCH] Remove old sh-sci driver"). 2. On modern SoCs, the sh-sci parent clock rate is no longer related to the CPU clock rate anyway, so using a cpufreq notifier is futile. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-13serial: sh-sci: Fix length of scatterlistYoshihiro Shimoda1-1/+1
This patch fixes an issue that the "length" of scatterlist should be set using sg_dma_len(). Otherwise, a dmaengine driver cannot work correctly if CONFIG_NEED_SG_DMA_LENGTH=y. Fixes: 7b39d90184 (serial: sh-sci: Fix NULL pointer dereference if HIGHMEM is enabled) Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Add DT support to DMA setupGeert Uytterhoeven1-31/+47
Add support for obtaining DMA channel information from the device tree. This requires switching from the legacy sh_dmae_slave structures with hardcoded channel numbers and the corresponding filter function to: 1. dma_request_slave_channel_compat(), - On legacy platforms, dma_request_slave_channel_compat() uses the passed DMA channel numbers that originate from platform device data, - On DT-based platforms, dma_request_slave_channel_compat() will retrieve the information from DT. 2. and the generic dmaengine_slave_config() configuration method, which requires filling in DMA register ports and slave bus widths. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Pause DMA engine and get DMA status againMuhammad Hamza Farooq1-0/+16
Occasionally, DMA transaction completes _after_ DMA engine is stopped. Verify if the transaction has not finished before forcing the engine to stop and push the data Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Do not terminate DMA engine when race condition occursMuhammad Hamza Farooq1-1/+6
When DMA packet completion and timer expiry take place at the same time, do not terminate the DMA engine, leading by submission of new descriptors, as the DMA communication hasn't necessarily stopped here. Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Call dma_async_issue_pending when transaction completesMuhammad Hamza Farooq1-0/+3
dmaengine_submit() will not start the DMA operation, it merely adds it to the pending queue. If the queue is no longer running, it won't be restarted until dma_async_issue_pending() is called. Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com> [geert: Add more description] Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Redirect port interrupts to CPU _only_ when DMA stopsMuhammad Hamza Farooq1-8/+10
Since the DMA engine is not stopped everytime rx_timer_fn is called, the interrupts have to be redirected back to CPU only when incomplete DMA transaction is handled Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Remove timer on shutdown of portAleksandar Mitev1-0/+8
This prevents DMA timer timeout that can trigger after the port has been closed. Signed-off-by: Aleksandar Mitev <amitev@visteon.com> [geert: Move del_timer_sync() outside spinlock to avoid circular locking dependency between rx_timer_fn() and del_timer_sync()] Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Stop calling sci_start_rx() from sci_request_dma()Geert Uytterhoeven1-1/+0
There's no need to call sci_start_rx() from sci_request_dma() when DMA setup fails, as sci_startup() will call sci_start_rx() anyway. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Submit RX DMA from RX interrupt on (H)SCIFGeert Uytterhoeven1-2/+5
For DMA receive requests, the driver is only notified by DMA completion after the whole DMA request has been transferred. If less data is received, it will stay stuck until more data arrives. The driver handles this by setting up a timer handler from the receive interrupt, after reception of the first character. Unlike SCIFA and SCIFB, SCIF and HSCIF don't issue receive interrupts on reception of individual characters if a receive DMA request is in progress, so the timer is never set up. To fix receive DMA on SCIF and HSCIF, submit the receive DMA request from the receive interrupt handler instead. In some sense this is similar to the SCIFA/SCIFB behavior, where the RDRQE (Rx Data Transfer Request Enable) bit is also set from the receive interrupt handler. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Get rid of the workqueue to handle receive DMA requestsGeert Uytterhoeven1-74/+61
The receive DMA workqueue function work_fn_rx() handles two things: 1. Reception of a full buffer on completion of a receive DMA request, 2. Reception of a partial buffer on receive DMA time-out. The workqueue is kicked by both the receive DMA completion handler, and by a timer to handle DMA time-out. As there are always two receive DMA requests active, it's possible that the receive DMA completion handler is called a second time before the workqueue function runs. As the time-out handler re-enables the receive interrupt, an interrupt may come in before time-out has been fully handled. Move part 1 into the receive DMA completion handler, and move part 2 into the receive DMA time-out handler, to fix these race conditions. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Shuffle functions aroundGeert Uytterhoeven1-456/+449
This allows to: - Remove forward declarations of static functions, - Coalesce two sections protected by #ifdef CONFIG_SERIAL_SH_SCI_DMA, - Avoid shuffling functions around in the near future, - Avoid adding forward declarations in the near future. No functional changes. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Don't call sci_dma_rx_push() if no data has arrivedGeert Uytterhoeven1-4/+5
On receive DMA time-out, avoid calling sci_dma_rx_push() if no data was transferred by the timed out DMA request. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Don't kick tx in sci_er_interrupt() when using DMAYoshihiro Shimoda1-1/+2
If CONFIG_SERIAL_SH_SCI_DMA is enabled, the driver doesn't enable TIE on SCIF or HSCIF. However, this driver may call sci_tx_interrupt() in sci_er_interrupt(). After that, the driver cannot care of the interrupt, and then "irq 109: nobody cared" happens on r8a7791/koelsch board. This patch fixes the issue. Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> [geert] Keep kicking tx when using PIO Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Don't call sci_rx_interrupt() on error when using DMAGeert Uytterhoeven1-1/+3
The error handler calls sci_rx_interrupt() to drain the receive FIFO if an error condition happens. However, if DMA is enabled on SCIFA or SCIFB, this will call disable_irq_nosync() twice. Due to this imbalance, the receive interrupt will never be re-enabled, and reception stops forever. To fix this, restrict draining the FIFO to PIO mode, and just call sci_receive_chars() directly. Inspired by a patch from Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>. Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Fix NULL pointer dereference if HIGHMEM is enabledYoshihiro Shimoda1-9/+9
This patch fixes an issue that this driver causes a NULL pointer dereference in the following conditions: - CONFIG_HIGHMEM and CONFIG_SERIAL_SH_SCI_DMA are enabled - This driver runs on the sci_dma_rx_push() This issue was caused by virt_to_page(buf) in the sci_request_dma() because this driver didn't check if the "buf" was valid or not. So, this patch uses the "buf" from dma_alloc_coherent() as is, not page. This patch also fixes a WARNING issue in sci_rx_dma_release(): WARNING: CPU: 0 PID: 1328 at lib/dma-debug.c:1125 check_unmap+0x444/0x848() rcar-dmac e6700000.dma-controller: DMA-API: device driver frees DMA memory with different CPU address [device address=0x000000006dd89000] [size=64 bytes] [cpu alloc address=0x000000016189c000] [cpu free address=0x0000000080000000] WARNING: CPU: 1 PID: 1 at drivers/base/dma-mapping.c:334 dma_common_free_remap+0x48/0x6c() trying to free invalid coherent area: (null) Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> [geert] Rebased [geert] Reworded [geert] Dropped .rx_chunk, as it's always identical to .rx_buf[0] Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Use incrementing pointers instead of stack arrayGeert Uytterhoeven1-14/+12
There's no need to keep all buffer and DMA pointers on the stack. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Use tty_insert_flip_string() for DMA receiveGeert Uytterhoeven1-12/+8
Switch from using tty_buffer_request_room() and looping over tty_insert_flip_char() to tty_insert_flip_string(). Keep track of buffer overruns in the icount structure, like serial_core.c does. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Pass scatterlist to sci_dma_rx_push()Geert Uytterhoeven1-24/+24
Currently sci_dma_rx_push() has to find the active scatterlist itself, but in some cases the caller already knows. Hence let the caller pass the scatterlist, and introduce a helper to find the active DMA request while we're at it. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Fix race condition between RX worker and cleanupGeert Uytterhoeven1-5/+14
During serial port shutdown, the DMA receive worker function may still be called after the receive DMA cleanup function has been called. Fix this race condition between work_fn_rx() and sci_rx_dma_release() by acquiring the port's spinlock in sci_rx_dma_release(). This requires releasing the spinlock in work_fn_rx() before calling (any function that may call) sci_rx_dma_release(). Terminate all active receive DMA descriptors to release them, and to make sure no more completions come in. Do the same in sci_tx_dma_release() for symmetry, although the serial upper layer will no longer submit more data at this point of time. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Fix exclusion of work_fn_rx and sci_dma_rx_completeKazuya Mizuguchi1-5/+7
There is a problem when the sci_dma_rx_complete() is processed before cancel process of work_fn_rx() completes by rx_timer_fn(). This patch locks work_fn_rx(). Signed-off-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com> Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Do not resubmit DMA descriptorsGeert Uytterhoeven1-12/+18
Resubmission of DMA descriptors is explicitly forbidden by the DMA engine API. Hence pass DMA_CTRL_ACK to dmaengine_prep_slave_sg(), and prepare a new DMA descriptor instead of reusing the old one. Remove sci_port.desc_rx[], as there's no longer a need to access the active descriptor. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Simplify sci_submit_rx() error handlingGeert Uytterhoeven1-20/+20
Simplify the error handling in sci_submit_rx() by - Moving it to the end of the function, - Just calling dmaengine_terminate_all() instead of calling async_tx_ack() for all already submitted descriptors. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Stop acknowledging DMA transmit completionsGeert Uytterhoeven1-5/+0
As dmaengine_prep_slave_sg() is called with the DMA_CTRL_ACK flag set for DMA transmit requests, there's no need to explicitly acknowledge DMA transmit requests in the DMA transmit completion callback. Hence remove the call to async_tx_ack(), and remove the now unused dma_async_tx_descriptor pointer in the sci_port structure. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Switch to generic DMA residue handlingGeert Uytterhoeven1-7/+9
Convert the SCI driver from the SHDMAE-specific partial DMA transfer handling to the generic dmaengine residual data framework. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Use DMA submission helpers instead of open-codingGeert Uytterhoeven1-7/+7
Replace open-coded - calls to dma_async_tx_descriptor.tx_submit() by calls to the dmaengine_submit() helper, - dma_cookie_t comparisons by calls to dma_submit_error(). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Fix TX buffer mapping leakGeert Uytterhoeven1-0/+2
The mapped transmit buffer is never unmapped. This leaks quite some mappings, as the mapping is done in uart_ops.startup(), i.e. every time the device is opened. Unmap the buffer on device close. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Switch to dma_map_single() for DMA transmissionGeert Uytterhoeven1-30/+20
Simplify the DMA transmit code by using dma_map_single() instead of constantly modifying the single-entry scatterlist to match what's currently being transmitted. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Use min_t()/max_t() instead of castsGeert Uytterhoeven1-2/+3
When comparing differently sized types, it's better to use min_t()/max_t() than adding casts. Also use "unsigned int" instead of "int", as that's the right type for the length of an SG entry. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Use correct device for DMA mapping with IOMMUGeert Uytterhoeven1-6/+8
To function correctly in the presence of an IOMMU, the DMA buffers must be managed using the DMA channel's device instead of the platform device's device. Make sure to free the DMA memory before releasing the channel, not after. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Handle DMA init failures inside sci_request_dma()Geert Uytterhoeven1-5/+7
Let sci_request_dma() handle failures to initialize DMA itself. This way sci_tx_dma_release() and sci_rx_dma_release() don't have to consider partial initialization, and thus don't need to reset DMA addresses to DMA_ERROR_CODE, which is not 100% portable access architectures. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Improve comments for DMA timeout calculationGeert Uytterhoeven1-7/+7
Reformat, grammar improvements, use "ms" instead of "msec". Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Improve DMA error messagesGeert Uytterhoeven1-11/+16
Make the life of the driver developer/debugger easier: - Add __func__ prefix to identical messages, - Add DMA directions to messages, - Add TX failure messages, - Always use "cookie %d" for DMA cookies, - "#%d" is reserved for the DMA cookie/descriptor index. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Return IRQ_HANDLED when overrun if detectedYoshihiro Shimoda1-1/+3
This patch fix an issue that the driver may cause "nobody cared" IRQ when this driver detects the overrun flag only. Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Remove bogus sci_handle_fifo_overrun() call on (H)SCIFGeert Uytterhoeven1-4/+1
Commit 8b6ff84c2d445a47 ("serial: sh-sci: Fix R-Car SCIF and HSCIF overrun handling") added overrun handling for (H)SCIF using the SCLSR register, but also accidentally added a bogus call to sci_handle_fifo_overrun() in the receive interrupt path. Remove it again. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Remove useless memory allocation failure printksGeert Uytterhoeven1-7/+2
Printing an error on memory allocation failures is unnecessary. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Make sci_regmap[] constGeert Uytterhoeven1-11/+11
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Make sci_irq_desc[] constGeert Uytterhoeven1-2/+2
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Improve readability of sampling rate configurationGeert Uytterhoeven1-9/+8
Reorder sampling_rate assignment for consistency in all cases of the switch statement. Avoid using the ternary conditional operator to make it more clear that the value is overridden by platform data. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Drop path in reference to serial_core.cGeert Uytterhoeven1-1/+1
serial_core.c was moved from drivers/serial/ to drivers/tty/serial/ a while ago. Remove the path to make it move-proof. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Use SCSMR_CKS instead of hardcoded literal 3Geert Uytterhoeven1-1/+1
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Use SCIF_DR instead of hardcoded literal 1Geert Uytterhoeven1-1/+2
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04serial: sh-sci: Correct SCIF_ERROR_CLEAR for plain SCIFGeert Uytterhoeven1-3/+11
SCIF_ERROR_CLEAR includes SCIFA_ORER, which exists only on SCIFA/SCIFB and SCIF on sh7705/sh7720/sh7721. To fix this: 1. Remove SCIFA_ORER from the definition of SCIF_ERROR_CLEAR, 2. During initialization, store the error clear mask to use, incorporating the overrun bit only if it applies to the SCxSR register. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>