This is a note to let you know that I've just added the patch titled
spi: sh-msiof: Avoid writing to registers from spi_master.setup()
to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: spi-sh-msiof-avoid-writing-to-registers-from-spi_master.setup.patch and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Thu Mar 22 14:03:39 CET 2018
From: Geert Uytterhoeven geert+renesas@glider.be Date: Wed, 13 Dec 2017 20:05:10 +0100 Subject: spi: sh-msiof: Avoid writing to registers from spi_master.setup()
From: Geert Uytterhoeven geert+renesas@glider.be
[ Upstream commit 7ff0b53c4051145d1cf992d2f60987e6447eed4f ]
The spi_master.setup() callback must not change configuration registers, as that could corrupt I/O that is in progress for other SPI slaves.
The only exception is the configuration of the native chip select polarity in SPI master mode, as a wrong chip select polarity will cause havoc during all future transfers to any other SPI slave.
Hence stop writing to registers in sh_msiof_spi_setup(), unless it is the first call for a controller using a native chip select, or unless native chip select polarity has changed (note that you'll loose anyway if I/O is in progress). Even then, only do what is strictly necessary, instead of calling sh_msiof_spi_set_pin_regs().
Signed-off-by: Geert Uytterhoeven geert+renesas@glider.be Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/spi/spi-sh-msiof.c | 35 ++++++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 11 deletions(-)
--- a/drivers/spi/spi-sh-msiof.c +++ b/drivers/spi/spi-sh-msiof.c @@ -55,6 +55,8 @@ struct sh_msiof_spi_priv { void *rx_dma_page; dma_addr_t tx_dma_addr; dma_addr_t rx_dma_addr; + bool native_cs_inited; + bool native_cs_high; bool slave_aborted; };
@@ -528,8 +530,7 @@ static int sh_msiof_spi_setup(struct spi { struct device_node *np = spi->master->dev.of_node; struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master); - - pm_runtime_get_sync(&p->pdev->dev); + u32 clr, set, tmp;
if (!np) { /* @@ -539,19 +540,31 @@ static int sh_msiof_spi_setup(struct spi spi->cs_gpio = (uintptr_t)spi->controller_data; }
- /* Configure pins before deasserting CS */ - sh_msiof_spi_set_pin_regs(p, !!(spi->mode & SPI_CPOL), - !!(spi->mode & SPI_CPHA), - !!(spi->mode & SPI_3WIRE), - !!(spi->mode & SPI_LSB_FIRST), - !!(spi->mode & SPI_CS_HIGH)); - - if (spi->cs_gpio >= 0) + if (spi->cs_gpio >= 0) { gpio_set_value(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH)); + return 0; + } + + if (spi_controller_is_slave(p->master)) + return 0;
+ if (p->native_cs_inited && + (p->native_cs_high == !!(spi->mode & SPI_CS_HIGH))) + return 0;
+ /* Configure native chip select mode/polarity early */ + clr = MDR1_SYNCMD_MASK; + set = MDR1_TRMD | TMDR1_PCON | MDR1_SYNCMD_SPI; + if (spi->mode & SPI_CS_HIGH) + clr |= BIT(MDR1_SYNCAC_SHIFT); + else + set |= BIT(MDR1_SYNCAC_SHIFT); + pm_runtime_get_sync(&p->pdev->dev); + tmp = sh_msiof_read(p, TMDR1) & ~clr; + sh_msiof_write(p, TMDR1, tmp | set); pm_runtime_put(&p->pdev->dev); - + p->native_cs_high = spi->mode & SPI_CS_HIGH; + p->native_cs_inited = true; return 0; }
Patches currently in stable-queue which might be from geert+renesas@glider.be are
queue-4.15/spi-sh-msiof-avoid-writing-to-registers-from-spi_master.setup.patch queue-4.15/pci-rcar-handle-rcar_pcie_parse_request_of_pci_ranges-failures.patch