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* | spi: bcm2835: Avoid 64-bit arithmetic in xfer len calcMartin Sperl2019-05-081-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid 64 bit aritmetics when deciding if we need to use polling or not This replicates: commit d704afffe65c ("spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc") from spi-bcm2835aux Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Changelog: V1 -> V2: applied feedback by Stefan Wahren reorganized patchset added extra rational, descriptions Signed-off-by: Mark Brown <broonie@kernel.org>
* | spi: bcm2835: bcm2835_spi_transfer_one_poll remove unnecessary argumentMartin Sperl2019-05-081-4/+2
|/ | | | | | | | | | | | | Remove the unnecessary argument of xfer_time_us when calling bcm2835_spi_transfer_one_poll. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Changelog: V1 -> V2: applied feedback by Stefan Wahren reorganized patchset added extra rational, descriptions Signed-off-by: Mark Brown <broonie@kernel.org>
* spi/spi-bcm2835: Split transfers that exceed DLENMeghana Madhyastha2019-05-021-28/+11
| | | | | | | | | | | | | | | | | | | | | | Split spi transfers into chunks of <=65532 to enable the driver to perform DMA transfer on big buffers. The DLEN register specifies the number of bytes to transfer in DMA mode. It is 16-bit wide and thus the maximum DMA transfer is 65535 bytes. Set the maximum to 65532 (4 byte aligned) since the FIFO in DMA mode is accessed in 4 byte chunks. ->max_dma_len is the value the spi core uses when splitting the buffer into scatter gather entries. The BCM2835 DMA block has 2 types of channels/engines: - Normal: Max length: 1G - Lite: Max length: 65535 Even when using a Lite channel we will not exceed the max length, so let's drop setting ->max_dma_len. Signed-off-by: Meghana Madhyastha <meghana.madhyastha@gmail.com> Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: Synchronize with callback on DMA terminationLukas Wunner2018-12-041-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit b36f09c3c441 ("dmaengine: Add transfer termination synchronization support") deprecated dmaengine_terminate_all() in favor of dmaengine_terminate_sync() and dmaengine_terminate_async() to avoid freeing resources used by the DMA callback before its execution has concluded. Commit de92436ac40f ("dmaengine: bcm2835-dma: Use vchan_terminate_vdesc() instead of desc_free") amended the BCM2835 DMA driver with an implementation of ->device_synchronize(), which is a prerequisite for dmaengine_terminate_sync(). Thus, clients of the DMA driver (such as the BCM2835 SPI driver) may now be converted to the new API. It is generally desirable to use the _sync() variant except in atomic context. There is only a single occurrence where the BCM2835 SPI driver calls dmaengine_terminate_all() in atomic context and that is in bcm2835_spi_dma_done() (the RX DMA channel's callback) to terminate the TX DMA channel. The TX DMA channel doesn't have a callback (yet), hence it is safe to use the _async() variant there. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Cc: Vinod Koul <vkoul@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: Speed up FIFO access if fill level is knownLukas Wunner2018-12-041-4/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The RX and TX FIFO of the BCM2835 SPI master each accommodate 64 bytes (16 32-bit dwords). The CS register provides hints on their fill level: "Bit 19 RXR - RX FIFO needs Reading ([¾] full) 0 = RX FIFO is less than [¾] full (or not active TA = 0). 1 = RX FIFO is [¾] or more full. Cleared by reading sufficient data from the RX FIFO or setting TA to 0." "Bit 16 DONE - Transfer Done 0 = Transfer is in progress (or not active TA = 0). 1 = Transfer is complete. Cleared by writing more data to the TX FIFO or setting TA to 0." "If DONE is set [...], write up to 16 [dwords] to SPI_FIFO. [...] If RXR is set read 12 [dwords] data from SPI_FIFO." [Source: Pages 153, 154 and 158 of https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf Note: The spec is missing the "¾" character, presumably due to copy-pasting from a different charset. It also incorrectly refers to 16 and 12 "bytes" instead of 32-bit dwords.] In short, the RXR bit indicates that 48 bytes can be read and the DONE bit indicates 64 bytes can be written. Leverage this knowledge to read or write bytes blindly to the FIFO, without polling whether data can be read or free space is available to write. Moreover, when a transfer is starting, the TX FIFO is known to be empty, likewise allowing a blind write of 64 bytes. This cuts the number of bus accesses in half if the fill level is known. Also, the (posted) write accesses can be pipelined on the AXI bus since they are no longer interleaved with (non-posted) reads. bcm2835_spi_transfer_one_poll() switches to interrupt mode when a time limit is exceeded by calling bcm2835_spi_transfer_one_irq(). The TX FIFO may contain data in this case, but is known to be empty when the function is called from bcm2835_spi_transfer_one(). Hence only blindly fill the TX FIFO in the latter case but not the former. Signed-off-by: Lukas Wunner <lukas@wunner.de> Tested-by: Eric Anholt <eric@anholt.net> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: Polish transfer of DMA prologueLukas Wunner2018-12-041-25/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 3bd7f6589f67 ("spi: bcm2835: Overcome sglist entry length limitation") was unfortunately merged even though submission of a refined version was imminent. Apply those refinements as an amendment: * Drop no longer needed #include <asm/page.h>. The lines requiring its inclusion were removed by the commit. * Change type of tx_spillover flag from bool to unsigned int for consistency with dma_pending flag and pursuant to Linus' dictum: https://lkml.org/lkml/2017/11/21/384 * In bcm2835_rd_fifo_count() do not check for bs->rx_buf != NULL. The function will never be called if that's the case. * Amend kerneldoc of bcm2835_wait_tx_fifo_empty() to prevent its use in situations where the function might spin forever. (In response to a review comment by Stefan Wahren.) * Sync only the cacheline containing the RX prologue back to memory, not the full first sglist entry. * Use sg_dma_address() and sg_dma_len() instead of referencing the sglist entry members directly. Seems to be the more common syntax in the tree, even for lvalues. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* Merge branch 'for-4.20' of ↵Mark Brown2018-11-291-1/+1
|\ | | | | | | https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi into spi-4.21
| * spi: bcm2835: Unbreak the build of esoteric configsLukas Wunner2018-11-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit e82b0b382845 ("spi: bcm2835: Fix race on DMA termination") broke the build with COMPILE_TEST=y on arches whose cmpxchg() requires 32-bit operands (xtensa, older arm ISAs). Fix by changing the dma_pending flag's type from bool to unsigned int. Fixes: e82b0b382845 ("spi: bcm2835: Fix race on DMA termination") Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org>
* | spi: bcm2835: Overcome sglist entry length limitationLukas Wunner2018-11-281-49/+242
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When in DMA mode, the BCM2835 SPI controller requires that the FIFO is accessed in 4 byte chunks. This rule is not fulfilled if a transfer consists of multiple sglist entries, one per page, and the first entry starts in the middle of a page with an offset not a multiple of 4. The driver currently falls back to programmed I/O for such transfers, incurring a significant performance penalty. Overcome this hardware limitation by transferring the first few bytes of a transfer without DMA such that the remainder of the first sglist entry becomes a multiple of 4. Specifics are provided in kerneldoc comments. An alternative approach would have been to split transfers in the ->prepare_message hook, but this may necessitate two transfers per page, defeating the goal of clustering multiple pages together in a single transfer for efficiency. E.g. if the first TX sglist entry's length is 23 and the first RX's is 40, the first transfer would send and receive 23 bytes, the second 40 - 23 = 17 bytes, the third 4096 - 17 = 4079 bytes, the fourth 4096 - 4079 = 17 bytes and so on. In other words, O(n) transfers are necessary (n = number of sglist entries), whereas the algorithm implemented herein only requires O(1) additional work. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Mathias Duckeck <m.duckeck@kunbus.de> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* | spi: bcm2835: Document struct bcm2835_spiLukas Wunner2018-11-281-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | Document the driver's data structure to lower the barrier to entry for contributors. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Mathias Duckeck <m.duckeck@kunbus.de> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* | spi: bcm2835: Drop unused code for native Chip SelectLukas Wunner2018-11-281-83/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit a30a555d7435 ("spi: bcm2835: transform native-cs to gpio-cs on first spi_setup") disabled the use of hardware-controlled native Chip Select in favour of software-controlled GPIO Chip Select but left code to support the former untouched. Remove it to simplify the driver and ease the addition of new features and further optimizations. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Mathias Duckeck <m.duckeck@kunbus.de> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* | Merge branch 'spi-4.20' into spi-4.21 for bcm stuff.Mark Brown2018-11-281-8/+6
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| * spi: bcm2835: Fix race on DMA terminationLukas Wunner2018-11-281-6/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a DMA transfer finishes orderly right when spi_transfer_one_message() determines that it has timed out, the callbacks bcm2835_spi_dma_done() and bcm2835_spi_handle_err() race to call dmaengine_terminate_all(), potentially leading to double termination. Prevent by atomically changing the dma_pending flag before calling dmaengine_terminate_all(). Signed-off-by: Lukas Wunner <lukas@wunner.de> Fixes: 3ecd37edaa2a ("spi: bcm2835: enable dma modes for transfers meeting certain conditions") Cc: stable@vger.kernel.org # v4.2+ Cc: Mathias Duckeck <m.duckeck@kunbus.de> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Mark Brown <broonie@kernel.org>
| * spi: bcm2835: Fix book-keeping of DMA terminationLukas Wunner2018-11-281-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If submission of a DMA TX transfer succeeds but submission of the corresponding RX transfer does not, the BCM2835 SPI driver terminates the TX transfer but neglects to reset the dma_pending flag to false. Thus, if the next transfer uses interrupt mode (because it is shorter than BCM2835_SPI_DMA_MIN_LENGTH) and runs into a timeout, dmaengine_terminate_all() will be called both for TX (once more) and for RX (which was never started in the first place). Fix it. Signed-off-by: Lukas Wunner <lukas@wunner.de> Fixes: 3ecd37edaa2a ("spi: bcm2835: enable dma modes for transfers meeting certain conditions") Cc: stable@vger.kernel.org # v4.2+ Cc: Mathias Duckeck <m.duckeck@kunbus.de> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Mark Brown <broonie@kernel.org>
| * spi: bcm2835: Avoid finishing transfer prematurely in IRQ modeLukas Wunner2018-11-281-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The IRQ handler bcm2835_spi_interrupt() first reads as much as possible from the RX FIFO, then writes as much as possible to the TX FIFO. Afterwards it decides whether the transfer is finished by checking if the TX FIFO is empty. If very few bytes were written to the TX FIFO, they may already have been transmitted by the time the FIFO's emptiness is checked. As a result, the transfer will be declared finished and the chip will be reset without reading the corresponding received bytes from the RX FIFO. The odds of this happening increase with a high clock frequency (such that the TX FIFO drains quickly) and either passing "threadirqs" on the command line or enabling CONFIG_PREEMPT_RT_BASE (such that the IRQ handler may be preempted between filling the TX FIFO and checking its emptiness). Fix by instead checking whether rx_len has reached zero, which means that the transfer has been received in full. This is also more efficient as it avoids one bus read access per interrupt. Note that bcm2835_spi_transfer_one_poll() likewise uses rx_len to determine whether the transfer has finished. Signed-off-by: Lukas Wunner <lukas@wunner.de> Fixes: e34ff011c70e ("spi: bcm2835: move to the transfer_one driver model") Cc: stable@vger.kernel.org # v4.1+ Cc: Mathias Duckeck <m.duckeck@kunbus.de> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* | spi: bcm2835: make license text and module license matchStefan Wahren2018-11-141-1/+1
|/ | | | | | | | | | | The license text is specifying GPL v2 or later but the MODULE_LICENSE is set to GPL v2 which means GNU Public License v2 only. So choose the license text as the correct one. Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> Acked-by: Florian Kauer <florian.kauer@koalo.de> Acked-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: Remove unnecessary workaround to call gpio_set_valueAxel Lin2016-02-151-5/+0
| | | | | | | | | This should be fixed by commit 4c02cba18cc9 ("pinctrl: bcm2835: Fix initial value for direction_output") Signed-off-by: Axel Lin <axel.lin@ingics.com> Acked-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
*-. Merge remote-tracking branches 'spi/topic/ath97', 'spi/topic/atmel', ↵Mark Brown2015-11-041-7/+7
|\ \ | | | | | | | | | 'spi/topic/au1550', 'spi/topic/bcm2835' and 'spi/topic/bcm2835aux' into spi-next
| | * spi: bcm2835: change initialization order and switch to platform_get_irqMartin Sperl2015-10-161-7/+7
| |/ | | | | | | | | | | | | | | | | | | Change the initialization order of the HW so that the interrupt is only requested after the HW is initialized Also the use of irq_of_parse_and_map is replaced by platform_get_irq. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
| |
| \
*-. \ Merge remote-tracking branches 'spi/fix/atmel', 'spi/fix/bcm2835', ↵Mark Brown2015-09-221-3/+3
|\ \ \ | |_|/ |/| | | | | 'spi/fix/doc', 'spi/fix/mediatek', 'spi/fix/meson', 'spi/fix/mtk' and 'spi/fix/pxa2xx' into spi-linus
| | * spi: bcm2835: BUG: fix wrong use of PAGE_MASKMartin Sperl2015-09-101-3/+3
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a bug in the alignment checking of transfers, that results in DMA not being used for un-aligned transfers that do not cross page-boundries, which is valid. This is due to a missconception of the meaning PAGE_MASK when implementing that check originally - (PAGE_SIZE - 1) should have been used instead. Also fixes a copy/paste error. Reported-by: <robert@axium.co.nz> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
* | spi: bcm2835: fix overflow in calculation of transfer timeMartin Sperl2015-07-291-4/+6
| | | | | | | | | | | | | | | | | | | | | | This resulted in the use of polling mode when other approaches (dma or interrupts) would have been more appropriate. Happened for transfers longer than 477 bytes. Reported-by: Noralf Tronnes <noralf@tronnes.org> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* | spi: bcm2835: set up spi-mode before asserting cs-gpioMartin Sperl2015-07-291-5/+23
|/ | | | | | | | | | | | | | | | | | | | | | | | When using reverse polarity for clock (spi-cpol) on a device the clock line gets altered after chip-select has been asserted resulting in an additional clock beat, which confuses hardware. This did not show when using native-CS, as the same register is used to control cs as well as polarity, so the changes came into effect at the same time. Unfortunately this is not true with gpio-cs. To avoid this situation this patch moves the setup of polarity (spi-cpol and spi-cpha) outside of the chip-select into prepare_message, which is run prior to asserting chip-select. Also fixes resetting 3-wire mode after use of rx-mode, so that a 3-Wire sequence TX, RX, TX works as well (right now it runs TX, RX, RX instead) Reported-by: Noralf Tronnes <noralf@tronnes.org> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
* spi: bcm2835: bcm2835_dma_release() can be statickbuild test robot2015-05-121-2/+2
| | | | | Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fix kbuild compile warnings/errors and a typoMartin Sperl2015-05-121-3/+5
| | | | | | | | | | | | | | | fixes several warnings/error emmitted by the kbuild system: * warn: cast from pointer to integer of different size using size_t instead of u32 * error: 'SZ_4K' undeclared moved to PAGE_SIZE and PAGE_MASK instead Review showed also a typo in the same code where tx_buff was checked twice instead of checking both rx and tx_buff. Reported by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: enable dma modes for transfers meeting certain conditionsMartin Sperl2015-05-111-2/+301
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conditions per spi_transfer are: * transfer.len >= 96 bytes (to avoid mapping overhead costs) * transfer.len < 65536 bytes (limitaion by spi-hw block - could get extended) * an individual scatter/gather transfer length must be a multiple of 4 for anything but the last transfer - spi-hw block limit. (some shortcut has been taken in can_dma to avoid unnecessary mapping of pages which, for which there is a chance that there is a split with a transfer length not a multiple of 4) If it becomes a necessity these restrictions can get removed by additional code. Note that this patch requires a patch to dma-bcm2835.c by Noralf to enable scatter-gather mode inside the dmaengine, which has not been merged yet. That is why no patch to arch/arm/boot/dts/bcm2835.dtsi is included - the code works as before without dma when tx/rx are not set, but it writes a message warning about dma not used: spi-bcm2835 20204000.spi: no tx-dma configuration found - not using dma mode To enable dma-mode add the following lines to the device-tree: dmas = <&dma 6>, <&dma 7>; dma-names = "tx", "rx"; Tested-by: Noralf Trønnes <noralf@tronnes.org> (private communication) Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fallback to interrupt for polling timeouts exceeding 2 jiffiesMartin Sperl2015-04-271-37/+50
| | | | | | | | | | | | | | | | | | The polling mode of the driver is designed for transfers that run less than 30us - it will only execute under those circumstances. So it should run comfortably without getting interrupted by the scheduler. But there are situations where the raspberry pi is so overloaded that it can take up to 80 jiffies until the polling thread gets rescheduled - this has been observed especially under heavy IO situations. In such a situation we now fall back to the interrupt handler and log the situation at debug level. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: change timeout of polling driver to 1sMartin Sperl2015-04-271-3/+2
| | | | | | | | | | | | | | The way that the timeout code is written in the polling function the timeout does also trigger when interrupted or rescheduled while in the polling loop. This patch changes the timeout from effectively 20ms (=2 jiffies) to 1 second and removes the time that the transfer really takes out of the computation, as - per design - this is <30us and the jiffie resolution is 10ms so that does not make any difference what so ever. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: enabling polling mode for transfers shorter than 30usMartin Sperl2015-04-101-26/+86
| | | | | | | | | | | | | | | | | | | | | | | | | | In cases of short transfer times the CPU is spending lots of time in the interrupt handler and scheduler to reschedule the worker thread. Measurements show that we have times where it takes 29.32us to between the last clock change and the time that the worker-thread is running again returning from wait_for_completion_timeout(). During this time the interrupt-handler is running calling complete() and then also the scheduler is rescheduling the worker thread. This time can vary depending on how much of the code is still in CPU-caches, when there is a burst of spi transfers the subsequent delays are in the order of 25us, so the value of 30us seems reasonable. With polling the whole transfer of 4 bytes at 10MHz finishes after 6.16us (CS down to up) with the real transfer (clock running) taking 3.56us. So the efficiency has much improved and is also freeing CPU cycles, reducing interrupts and context switches. Because of the above 30us seems to be a reasonable limit for polling. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: transform native-cs to gpio-cs on first spi_setupMartin Sperl2015-04-101-5/+44
| | | | | | | | | | | | | | | | | Transforms the bcm-2835 native SPI-chip select to their gpio-cs equivalent. This allows for some support of some optimizations that are not possible due to HW-gliches on the CS line - especially filling the FIFO before enabling SPI interrupts (by writing to CS register) while the transfer is already in progress (See commit: e3a2be3030e2) This patch also works arround some issues in bcm2835-pinctrl which does not set the value when setting the GPIO as output - it just sets up output and (typically) leaves the GPIO as low. When a fix for this is merged then this gpio_set_value can get removed from bcm2835_spi_setup. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fill FIFO before enabling interrupts to reduce interrupts/messageMartin Sperl2015-03-291-0/+16
| | | | | | | | | | | | | | To reduce the number of interrupts/message we fill the FIFO before enabling interrupts - for short messages this reduces the interrupt count from 2 to 1 interrupt. There have been rare cases where short (<200ns) chip-select switches with native CS have been observed during such operation, this is why this optimization is only enabled for GPIO-CS. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Tested-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fix code formatting issueMartin Sperl2015-03-291-2/+1
| | | | | | Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Tested-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: move to the transfer_one driver modelMartin Sperl2015-03-271-88/+124
| | | | | | | | | | | | | | | | | | | | | | This also allows for GPIO-CS to get used removing the limitation of 2/3 SPI devises on the SPI bus. Fixes: spi-cs-high with native CS with multiple devices on the spi-bus resetting the chip selects to "normal" polarity after a finished transfer. No other functionality/improvements added. Tested with the following 4 devices on the spi-bus: * mcp2515 with native CS * mcp2515 with gpio CS * fb_st7735r with native CS (plus spi-cs-high via transistor inverting polarity) * enc28j60 with gpio-CS Tested-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: enable support of 3-wire modeMartin Sperl2015-03-231-1/+5
| | | | | Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: clock divider can be a multiple of 2Martin Sperl2015-03-231-2/+3
| | | | | | | | The official documentation is wrong in this respect. Has been tested empirically for dividers 2-1024 Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fill/drain SPI-fifo as much as possible during interruptMartin Sperl2015-03-231-61/+17
| | | | | | | | | | | | | | | Implement the recommendation from the BCM2835 data-sheet with regards to polling drivers to fill/drain the FIFO as much data as possible also for the interrupt-driven case (which this driver is making use of). This means that for long transfers (>64bytes) we need one interrupt every 64 bytes instead of every 12 bytes, as the FIFO is 16 words (not bytes) wide. Tested with mcp251x (can bus), fb_st7735 (TFT framebuffer device) and enc28j60 (ethernet) drivers. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fix all checkpath --strict messagesMartin Sperl2015-03-201-7/+11
| | | | | | | | | | | | | | | | | The following errors/warnings issued by checkpatch.pl --strict have been fixed: drivers/spi/spi-bcm2835.c:182: CHECK: Alignment should match open parenthesis drivers/spi/spi-bcm2835.c:191: CHECK: braces {} should be used on all arms of this statement drivers/spi/spi-bcm2835.c:234: CHECK: Alignment should match open parenthesis drivers/spi/spi-bcm2835.c:256: CHECK: Alignment should match open parenthesis drivers/spi/spi-bcm2835.c:271: CHECK: Alignment should match open parenthesis drivers/spi/spi-bcm2835.c:346: CHECK: Alignment should match open parenthesis total: 0 errors, 0 warnings, 6 checks, 403 lines checked In 2 locations the arguments had to get split/moved to the next line so that the line width stays below 80 chars. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: Remove FSF mailing addressesJarkko Nikula2014-12-221-4/+0
| | | | | Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: drop owner assignment from platform_driversWolfram Sang2014-10-201-1/+0
| | | | | | | A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
* spi: Remove explictly set bus_num and num_chipselect to default settingAxel Lin2014-02-161-1/+0
| | | | | | | | | | | | | The purpose of commit 1e8a52e18cfb "spi: By default setup spi_masters with 1 chipselect and dynamics bus number" is to avoid setting default value for bus_num and num_chipselect in spi master drivers. So let's remove the duplicate code. Signed-off-by: Axel Lin <axel.lin@ingics.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-By: David Daney <david.daney@cavium.com> Acked-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bcm2835: Use devm_request_irq()Jingoo Han2013-12-171-7/+3
| | | | | | | Use devm_request_irq() to make cleanup paths simpler. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Mark Brown <broonie@linaro.org>
*-. Merge remote-tracking branches 'spi/fix/bcm2835', 'spi/fix/bcm63xx', ↵Mark Brown2013-11-281-1/+1
|\ \ | | | | | | | | | 'spi/fix/mpc512x-psc', 'spi/fix/mxs', 'spi/fix/pxa2xx', 'spi/fix/qspi', 'spi/fix/rspi' and 'spi/fix/txx9' into spi-linus
| * | spi: bcm2835: fix reference leak to master in bcm2835_spi_remove()Wei Yongjun2013-11-151-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | Once a spi_master_get() call succeeds, we need an additional spi_master_put() call to free the memory, otherwise we will leak a reference to master. Fix by removing the unnecessary spi_master_get() call. Fixes: 247263dba208 ('spi: bcm2835: use devm_spi_register_master()') Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Mark Brown <broonie@linaro.org>
* / tree-wide: use reinit_completion instead of INIT_COMPLETIONWolfram Sang2013-11-151-1/+1
|/ | | | | | | | | | | | Use this new function to make code more comprehensible, since we are reinitialzing the completion, not initializing. [akpm@linux-foundation.org: linux-next resyncs] Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13) Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* spi: bcm2835: use devm_spi_register_master()Jingoo Han2013-09-261-3/+1
| | | | | | | | Use devm_spi_register_master() to make cleanup paths simpler, and remove a duplicate put. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bcm2835: Add spi_master_get() call to prevent use after freeAxel Lin2013-08-221-1/+1
| | | | | | | | | | | | | The call to spi_unregister_master results in device memory being freed, it must no longer be accessed afterwards. Thus call spi_master_get() to get an extra reference to the device and call spi_master_put() only after the last access to device data. Note, current code has an extra spi_master_put() call in bcm2835_spi_remove(). Thus this patch just adds an spi_master_get() to balance the reference count. Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bcm2835: Use SPI_BPW_MASK macro for bits_per_word_mask settingAxel Lin2013-08-051-1/+1
| | | | | | | We have a SPI_BPW_MASK macro defined in spi.h, use it instead of open-coded. Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bcm2835: don't check resource with devm_ioremap_resourceWolfram Sang2013-07-241-6/+0
| | | | | | | | devm_ioremap_resource does sanity checks on the given resource. No need to duplicate this in the driver. Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bmc2835: use devm_ioremap_resource()Laurent Navet2013-05-131-4/+3
| | | | | | | | | | Replace a call to deprecated devm_request_and_ioremap by devm_ioremap_resource. Found with coccicheck and this semantic patch: scripts/coccinelle/api/devm_request_and_ioremap.cocci. Signed-off-by: Laurent Navet <laurent.navet@gmail.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
* spi: bcm2835: make use of new bits_per_word_mask core featureStephen Warren2013-04-011-35/+1
| | | | | | | | This driver only supports bits_per_word==8, so inform the SPI core of this. Remove all the open-coded validation that's no longer needed. Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-20 11:55:18 +0100