From 2922a8de996956893bb98e4aa91be9774c958336 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Tue, 21 May 2013 20:36:34 -0600 Subject: spi: introduce macros to set bits_per_word_mask Introduce two macros to make setting up spi_master.bits_per_word_mask easier, and avoid mistakes like writing BIT(n) instead of BIT(n - 1). SPI_BPW_MASK is for a single supported value of bits_per_word_mask. SPI_BPW_RANGE_MASK represents a contiguous set of bit lengths. Signed-off-by: Stephen Warren Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 6ff26c8db7b9..173725622252 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -308,6 +308,8 @@ struct spi_master { /* bitmask of supported bits_per_word for transfers */ u32 bits_per_word_mask; +#define SPI_BPW_MASK(bits) BIT((bits) - 1) +#define SPI_BPW_RANGE_MASK(min, max) ((BIT(max) - 1) - (BIT(min) - 1)) /* other constraints relevant to this driver */ u16 flags; -- cgit v1.2.3 From 4dd9572abc224019a042b662fb0eececca283cb9 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Thu, 30 May 2013 09:59:39 -0600 Subject: spi: fix undefined behaviour in SPI_BPW_RANGE_MASK The parameters to SPI_BPW_RANGE_MASK() are in the range 1..32. If 32 is used as a parameter, part of the expression is "1 << 32". Since 32 is >= the size of the type in use, such a shift is undefined behaviour. Add macro SPI_BIT_MASK to Implement a special case and thus avoid undefined behaviour. Use this new macro rather than BIT() when implementing SPI_BPW_RANGE_MASK(). This fixes build warnings such as: drivers/spi/spi-gpio.c:446:2: warning: left shift count >= width of type [enabled by default] SPI_BPW_MASK() already avoids this, since its parameter is also in range 1..32, yet it only shifts by up to one less than the input parameter. Reported-by: Fengguang Wu Signed-off-by: Stephen Warren Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 173725622252..3e9479134d9d 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -309,7 +309,8 @@ struct spi_master { /* bitmask of supported bits_per_word for transfers */ u32 bits_per_word_mask; #define SPI_BPW_MASK(bits) BIT((bits) - 1) -#define SPI_BPW_RANGE_MASK(min, max) ((BIT(max) - 1) - (BIT(min) - 1)) +#define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0UL : (BIT(bits) - 1)) +#define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min)) /* other constraints relevant to this driver */ u16 flags; -- cgit v1.2.3 From eca8960a8e0f48dc62c1063bcc33a626455d766e Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Thu, 30 May 2013 09:59:40 -0600 Subject: spi: fix incorrect handling of min param in SPI_BPW_RANGE_MASK SPI_BPW_RANGE_MASK is intended to work by calculating two masks; one representing support for all bits up-to-and-including the "max" supported value, and one representing support for all bits up-to-but-not-including the "min" supported value, and then taking the difference between the two, resulting in a mask representing support for all bits between (inclusive) the min and max values. However, the second mask ended up representing all bits up-to-and- including rather up-to-but-not-including. Fix this bug. Signed-off-by: Stephen Warren Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 3e9479134d9d..28e440be1c07 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -310,7 +310,7 @@ struct spi_master { u32 bits_per_word_mask; #define SPI_BPW_MASK(bits) BIT((bits) - 1) #define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0UL : (BIT(bits) - 1)) -#define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min)) +#define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min - 1)) /* other constraints relevant to this driver */ u16 flags; -- cgit v1.2.3 From 082339bc63cccf8ea49b1f3cf4ee39ce00742849 Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Tue, 4 Jun 2013 16:02:36 +0200 Subject: spi: spi-xilinx: Add run run-time endian detection Do not load endian value from platform data and rather autodetect it. Signed-off-by: Michal Simek Signed-off-by: Mark Brown --- drivers/mfd/timberdale.c | 1 - drivers/spi/spi-xilinx.c | 29 +++++++++++++++++++++-------- include/linux/spi/xilinx_spi.h | 1 - 3 files changed, 21 insertions(+), 10 deletions(-) (limited to 'include/linux') diff --git a/drivers/mfd/timberdale.c b/drivers/mfd/timberdale.c index 59e0ee247e86..0c1fcbc23d04 100644 --- a/drivers/mfd/timberdale.c +++ b/drivers/mfd/timberdale.c @@ -145,7 +145,6 @@ static struct spi_board_info timberdale_spi_8bit_board_info[] = { static struct xspi_platform_data timberdale_xspi_platform_data = { .num_chipselect = 3, - .little_endian = true, /* bits per word and devices will be filled in runtime depending * on the HW config */ diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c index e1d769607425..bb6ae4ee7dea 100644 --- a/drivers/spi/spi-xilinx.c +++ b/drivers/spi/spi-xilinx.c @@ -30,6 +30,7 @@ */ #define XSPI_CR_OFFSET 0x60 /* Control Register */ +#define XSPI_CR_LOOP 0x01 #define XSPI_CR_ENABLE 0x02 #define XSPI_CR_MASTER_MODE 0x04 #define XSPI_CR_CPOL 0x08 @@ -359,11 +360,12 @@ static const struct of_device_id xilinx_spi_of_match[] = { MODULE_DEVICE_TABLE(of, xilinx_spi_of_match); struct spi_master *xilinx_spi_init(struct device *dev, struct resource *mem, - u32 irq, s16 bus_num, int num_cs, int little_endian, int bits_per_word) + u32 irq, s16 bus_num, int num_cs, int bits_per_word) { struct spi_master *master; struct xilinx_spi *xspi; int ret; + u32 tmp; master = spi_alloc_master(dev, sizeof(struct xilinx_spi)); if (!master) @@ -396,13 +398,25 @@ struct spi_master *xilinx_spi_init(struct device *dev, struct resource *mem, xspi->mem = *mem; xspi->irq = irq; - if (little_endian) { - xspi->read_fn = xspi_read32; - xspi->write_fn = xspi_write32; - } else { + + /* + * Detect endianess on the IP via loop bit in CR. Detection + * must be done before reset is sent because incorrect reset + * value generates error interrupt. + * Setup little endian helper functions first and try to use them + * and check if bit was correctly setup or not. + */ + xspi->read_fn = xspi_read32; + xspi->write_fn = xspi_write32; + + xspi->write_fn(XSPI_CR_LOOP, xspi->regs + XSPI_CR_OFFSET); + tmp = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET); + tmp &= XSPI_CR_LOOP; + if (tmp != XSPI_CR_LOOP) { xspi->read_fn = xspi_read32_be; xspi->write_fn = xspi_write32_be; } + xspi->bits_per_word = bits_per_word; if (xspi->bits_per_word == 8) { xspi->tx_fn = xspi_tx8; @@ -466,14 +480,13 @@ static int xilinx_spi_probe(struct platform_device *dev) { struct xspi_platform_data *pdata; struct resource *r; - int irq, num_cs = 0, little_endian = 0, bits_per_word = 8; + int irq, num_cs = 0, bits_per_word = 8; struct spi_master *master; u8 i; pdata = dev->dev.platform_data; if (pdata) { num_cs = pdata->num_chipselect; - little_endian = pdata->little_endian; bits_per_word = pdata->bits_per_word; } @@ -505,7 +518,7 @@ static int xilinx_spi_probe(struct platform_device *dev) return -ENXIO; master = xilinx_spi_init(&dev->dev, r, irq, dev->id, num_cs, - little_endian, bits_per_word); + bits_per_word); if (!master) return -ENODEV; diff --git a/include/linux/spi/xilinx_spi.h b/include/linux/spi/xilinx_spi.h index 6f17278810b0..333ecdfee0d9 100644 --- a/include/linux/spi/xilinx_spi.h +++ b/include/linux/spi/xilinx_spi.h @@ -11,7 +11,6 @@ */ struct xspi_platform_data { u16 num_chipselect; - bool little_endian; u8 bits_per_word; struct spi_board_info *devices; u8 num_devices; -- cgit v1.2.3