Unrated severityNVD Advisory· Published May 28, 2026
CVE-2026-46148
CVE-2026-46148
Description
In the Linux kernel, the following vulnerability has been resolved:
spi: microchip-core-qspi: control built-in cs manually
The coreQSPI IP supports only a single chip select, which is automagically operated by the hardware - set low when the transmit buffer first gets written to and set high when the number of bytes written to the TOTALBYTES field of the FRAMES register have been sent on the bus. Additional devices must use GPIOs for their chip selects. It was reported to me that if there are two devices attached to this QSPI controller that the in-built chip select is set low while linux tries to access the device attached to the GPIO.
This went undetected as the boards that connected multiple devices to the SPI controller all exclusively used GPIOs for chip selects, not relying on the built-in chip select at all. It turns out that this was because the built-in chip select, when controlled automagically, is set low when active and high when inactive, thereby ruling out its use for active-high devices or devices that need to transmit with the chip select disabled.
Modify the driver so that it controls chip select directly, retaining the behaviour for mem_ops of setting the chip select active for the entire duration of the transfer in the exec_op callback. For regular transfers, implement the set_cs callback for the core to use.
As part of this, the existing setup callback, mchp_coreqspi_setup_op(), is removed. Modifying the CLKIDLE field is not safe to do during operation when there are multiple devices, so this code is removed entirely. Setting the MASTER and ENABLE fields is something that can be done once at probe, it doesn't need to be re-run for each device. Instead the new setup callback sets the built-in chip select to its inactive state for active-low devices, as the reset value of the chip select in software controlled mode is low.
Affected products
2Patches
6998f43196d73spi: microchip-core-qspi: control built-in cs manually
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitConor DooleyApr 30, 2026Fixed in 6.18.30via kernel-cna
1 file changed · +64 −16
drivers/spi/spi-microchip-core-qspi.c+64 −16 modifieddiff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c index 6b7d350dd53d83..70215a407b5a32 100644 --- a/drivers/spi/spi-microchip-core-qspi.c +++ b/drivers/spi/spi-microchip-core-qspi.c @@ -74,6 +74,13 @@ #define STATUS_FLAGSX4 BIT(8) #define STATUS_MASK GENMASK(8, 0) +/* + * QSPI Direct Access register defines + */ +#define DIRECT_ACCESS_EN_SSEL BIT(0) +#define DIRECT_ACCESS_OP_SSEL BIT(1) +#define DIRECT_ACCESS_OP_SSEL_SHIFT 1 + #define BYTESUPPER_MASK GENMASK(31, 16) #define BYTESLOWER_MASK GENMASK(15, 0) @@ -158,6 +165,38 @@ static int mchp_coreqspi_set_mode(struct mchp_coreqspi *qspi, const struct spi_m return 0; } +static void mchp_coreqspi_set_cs(struct spi_device *spi, bool enable) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + + val &= ~DIRECT_ACCESS_OP_SSEL; + val |= !enable << DIRECT_ACCESS_OP_SSEL_SHIFT; + + writel(val, qspi->regs + REG_DIRECT_ACCESS); +} + +static int mchp_coreqspi_setup(struct spi_device *spi) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + /* + * Active low devices need to be specifically set to their inactive + * states during probe. + */ + if (spi->mode & SPI_CS_HIGH) + return 0; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_OP_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + + return 0; +} + static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi) { u32 control, data; @@ -380,19 +419,6 @@ static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi, struct spi_devi return 0; } -static int mchp_coreqspi_setup_op(struct spi_device *spi_dev) -{ - struct spi_controller *ctlr = spi_dev->controller; - struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr); - u32 control = readl_relaxed(qspi->regs + REG_CONTROL); - - control |= (CONTROL_MASTER | CONTROL_ENABLE); - control &= ~CONTROL_CLKIDLE; - writel_relaxed(control, qspi->regs + REG_CONTROL); - - return 0; -} - static inline void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op) { u32 idle_cycles = 0; @@ -483,6 +509,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o reinit_completion(&qspi->data_completion); mchp_coreqspi_config_op(qspi, op); + mchp_coreqspi_set_cs(mem->spi, true); if (op->cmd.opcode) { qspi->txbuf = &opcode; qspi->rxbuf = NULL; @@ -523,6 +550,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o err = -ETIMEDOUT; error: + mchp_coreqspi_set_cs(mem->spi, false); mutex_unlock(&qspi->op_lock); mchp_coreqspi_disable_ints(qspi); @@ -696,6 +724,7 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; int ret; + u32 num_cs, val; ctlr = devm_spi_alloc_host(&pdev->dev, sizeof(*qspi)); if (!ctlr) @@ -728,10 +757,18 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) return ret; } + /* + * The IP core only has a single CS, any more have to be provided via + * gpios + */ + if (of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs)) + num_cs = 1; + + ctlr->num_chipselect = num_cs; + ctlr->bits_per_word_mask = SPI_BPW_MASK(8); ctlr->mem_ops = &mchp_coreqspi_mem_ops; ctlr->mem_caps = &mchp_coreqspi_mem_caps; - ctlr->setup = mchp_coreqspi_setup_op; ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD; ctlr->dev.of_node = np; @@ -739,9 +776,21 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) ctlr->prepare_message = mchp_coreqspi_prepare_message; ctlr->unprepare_message = mchp_coreqspi_unprepare_message; ctlr->transfer_one = mchp_coreqspi_transfer_one; - ctlr->num_chipselect = 2; + ctlr->setup = mchp_coreqspi_setup; + ctlr->set_cs = mchp_coreqspi_set_cs; ctlr->use_gpio_descriptors = true; + val = readl_relaxed(qspi->regs + REG_CONTROL); + val |= (CONTROL_MASTER | CONTROL_ENABLE); + writel_relaxed(val, qspi->regs + REG_CONTROL); + + /* + * Put cs into software controlled mode + */ + val = readl_relaxed(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_EN_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + ret = spi_register_controller(ctlr); if (ret) return dev_err_probe(&pdev->dev, ret, -- cgit 1.3-korg
ee3c99aa1022spi: microchip-core-qspi: control built-in cs manually
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitConor DooleyApr 30, 2026Fixed in 7.0.7via kernel-cna
1 file changed · +64 −16
drivers/spi/spi-microchip-core-qspi.c+64 −16 modifieddiff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c index 6b7d350dd53d83..70215a407b5a32 100644 --- a/drivers/spi/spi-microchip-core-qspi.c +++ b/drivers/spi/spi-microchip-core-qspi.c @@ -74,6 +74,13 @@ #define STATUS_FLAGSX4 BIT(8) #define STATUS_MASK GENMASK(8, 0) +/* + * QSPI Direct Access register defines + */ +#define DIRECT_ACCESS_EN_SSEL BIT(0) +#define DIRECT_ACCESS_OP_SSEL BIT(1) +#define DIRECT_ACCESS_OP_SSEL_SHIFT 1 + #define BYTESUPPER_MASK GENMASK(31, 16) #define BYTESLOWER_MASK GENMASK(15, 0) @@ -158,6 +165,38 @@ static int mchp_coreqspi_set_mode(struct mchp_coreqspi *qspi, const struct spi_m return 0; } +static void mchp_coreqspi_set_cs(struct spi_device *spi, bool enable) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + + val &= ~DIRECT_ACCESS_OP_SSEL; + val |= !enable << DIRECT_ACCESS_OP_SSEL_SHIFT; + + writel(val, qspi->regs + REG_DIRECT_ACCESS); +} + +static int mchp_coreqspi_setup(struct spi_device *spi) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + /* + * Active low devices need to be specifically set to their inactive + * states during probe. + */ + if (spi->mode & SPI_CS_HIGH) + return 0; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_OP_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + + return 0; +} + static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi) { u32 control, data; @@ -380,19 +419,6 @@ static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi, struct spi_devi return 0; } -static int mchp_coreqspi_setup_op(struct spi_device *spi_dev) -{ - struct spi_controller *ctlr = spi_dev->controller; - struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr); - u32 control = readl_relaxed(qspi->regs + REG_CONTROL); - - control |= (CONTROL_MASTER | CONTROL_ENABLE); - control &= ~CONTROL_CLKIDLE; - writel_relaxed(control, qspi->regs + REG_CONTROL); - - return 0; -} - static inline void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op) { u32 idle_cycles = 0; @@ -483,6 +509,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o reinit_completion(&qspi->data_completion); mchp_coreqspi_config_op(qspi, op); + mchp_coreqspi_set_cs(mem->spi, true); if (op->cmd.opcode) { qspi->txbuf = &opcode; qspi->rxbuf = NULL; @@ -523,6 +550,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o err = -ETIMEDOUT; error: + mchp_coreqspi_set_cs(mem->spi, false); mutex_unlock(&qspi->op_lock); mchp_coreqspi_disable_ints(qspi); @@ -696,6 +724,7 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; int ret; + u32 num_cs, val; ctlr = devm_spi_alloc_host(&pdev->dev, sizeof(*qspi)); if (!ctlr) @@ -728,10 +757,18 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) return ret; } + /* + * The IP core only has a single CS, any more have to be provided via + * gpios + */ + if (of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs)) + num_cs = 1; + + ctlr->num_chipselect = num_cs; + ctlr->bits_per_word_mask = SPI_BPW_MASK(8); ctlr->mem_ops = &mchp_coreqspi_mem_ops; ctlr->mem_caps = &mchp_coreqspi_mem_caps; - ctlr->setup = mchp_coreqspi_setup_op; ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD; ctlr->dev.of_node = np; @@ -739,9 +776,21 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) ctlr->prepare_message = mchp_coreqspi_prepare_message; ctlr->unprepare_message = mchp_coreqspi_unprepare_message; ctlr->transfer_one = mchp_coreqspi_transfer_one; - ctlr->num_chipselect = 2; + ctlr->setup = mchp_coreqspi_setup; + ctlr->set_cs = mchp_coreqspi_set_cs; ctlr->use_gpio_descriptors = true; + val = readl_relaxed(qspi->regs + REG_CONTROL); + val |= (CONTROL_MASTER | CONTROL_ENABLE); + writel_relaxed(val, qspi->regs + REG_CONTROL); + + /* + * Put cs into software controlled mode + */ + val = readl_relaxed(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_EN_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + ret = spi_register_controller(ctlr); if (ret) return dev_err_probe(&pdev->dev, ret, -- cgit 1.3-korg
7672749e1496spi: microchip-core-qspi: control built-in cs manually
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitConor DooleyApr 30, 2026Fixed in 7.1-rc3via kernel-cna
1 file changed · +64 −16
drivers/spi/spi-microchip-core-qspi.c+64 −16 modifieddiff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c index eab059fb0bc2ce..ffa0f33a0ae099 100644 --- a/drivers/spi/spi-microchip-core-qspi.c +++ b/drivers/spi/spi-microchip-core-qspi.c @@ -74,6 +74,13 @@ #define STATUS_FLAGSX4 BIT(8) #define STATUS_MASK GENMASK(8, 0) +/* + * QSPI Direct Access register defines + */ +#define DIRECT_ACCESS_EN_SSEL BIT(0) +#define DIRECT_ACCESS_OP_SSEL BIT(1) +#define DIRECT_ACCESS_OP_SSEL_SHIFT 1 + #define BYTESUPPER_MASK GENMASK(31, 16) #define BYTESLOWER_MASK GENMASK(15, 0) @@ -158,6 +165,38 @@ static int mchp_coreqspi_set_mode(struct mchp_coreqspi *qspi, const struct spi_m return 0; } +static void mchp_coreqspi_set_cs(struct spi_device *spi, bool enable) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + + val &= ~DIRECT_ACCESS_OP_SSEL; + val |= !enable << DIRECT_ACCESS_OP_SSEL_SHIFT; + + writel(val, qspi->regs + REG_DIRECT_ACCESS); +} + +static int mchp_coreqspi_setup(struct spi_device *spi) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + /* + * Active low devices need to be specifically set to their inactive + * states during probe. + */ + if (spi->mode & SPI_CS_HIGH) + return 0; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_OP_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + + return 0; +} + static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi) { u32 control, data; @@ -380,19 +419,6 @@ static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi, struct spi_devi return 0; } -static int mchp_coreqspi_setup_op(struct spi_device *spi_dev) -{ - struct spi_controller *ctlr = spi_dev->controller; - struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr); - u32 control = readl_relaxed(qspi->regs + REG_CONTROL); - - control |= (CONTROL_MASTER | CONTROL_ENABLE); - control &= ~CONTROL_CLKIDLE; - writel_relaxed(control, qspi->regs + REG_CONTROL); - - return 0; -} - static inline void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op) { u32 idle_cycles = 0; @@ -483,6 +509,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o reinit_completion(&qspi->data_completion); mchp_coreqspi_config_op(qspi, op); + mchp_coreqspi_set_cs(mem->spi, true); if (op->cmd.opcode) { qspi->txbuf = &opcode; qspi->rxbuf = NULL; @@ -523,6 +550,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o err = -ETIMEDOUT; error: + mchp_coreqspi_set_cs(mem->spi, false); mutex_unlock(&qspi->op_lock); mchp_coreqspi_disable_ints(qspi); @@ -686,6 +714,7 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; int ret; + u32 num_cs, val; ctlr = devm_spi_alloc_host(&pdev->dev, sizeof(*qspi)); if (!ctlr) @@ -718,10 +747,18 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) return ret; } + /* + * The IP core only has a single CS, any more have to be provided via + * gpios + */ + if (of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs)) + num_cs = 1; + + ctlr->num_chipselect = num_cs; + ctlr->bits_per_word_mask = SPI_BPW_MASK(8); ctlr->mem_ops = &mchp_coreqspi_mem_ops; ctlr->mem_caps = &mchp_coreqspi_mem_caps; - ctlr->setup = mchp_coreqspi_setup_op; ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD; ctlr->dev.of_node = np; @@ -729,9 +766,21 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) ctlr->prepare_message = mchp_coreqspi_prepare_message; ctlr->unprepare_message = mchp_coreqspi_unprepare_message; ctlr->transfer_one = mchp_coreqspi_transfer_one; - ctlr->num_chipselect = 2; + ctlr->setup = mchp_coreqspi_setup; + ctlr->set_cs = mchp_coreqspi_set_cs; ctlr->use_gpio_descriptors = true; + val = readl_relaxed(qspi->regs + REG_CONTROL); + val |= (CONTROL_MASTER | CONTROL_ENABLE); + writel_relaxed(val, qspi->regs + REG_CONTROL); + + /* + * Put cs into software controlled mode + */ + val = readl_relaxed(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_EN_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + ret = spi_register_controller(ctlr); if (ret) return dev_err_probe(&pdev->dev, ret, -- cgit 1.3-korg
7672749e1496spi: microchip-core-qspi: control built-in cs manually
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gitConor DooleyApr 30, 2026via nvd-ref
1 file changed · +64 −16
drivers/spi/spi-microchip-core-qspi.c+64 −16 modifieddiff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c index eab059fb0bc2ce..ffa0f33a0ae099 100644 --- a/drivers/spi/spi-microchip-core-qspi.c +++ b/drivers/spi/spi-microchip-core-qspi.c @@ -74,6 +74,13 @@ #define STATUS_FLAGSX4 BIT(8) #define STATUS_MASK GENMASK(8, 0) +/* + * QSPI Direct Access register defines + */ +#define DIRECT_ACCESS_EN_SSEL BIT(0) +#define DIRECT_ACCESS_OP_SSEL BIT(1) +#define DIRECT_ACCESS_OP_SSEL_SHIFT 1 + #define BYTESUPPER_MASK GENMASK(31, 16) #define BYTESLOWER_MASK GENMASK(15, 0) @@ -158,6 +165,38 @@ static int mchp_coreqspi_set_mode(struct mchp_coreqspi *qspi, const struct spi_m return 0; } +static void mchp_coreqspi_set_cs(struct spi_device *spi, bool enable) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + + val &= ~DIRECT_ACCESS_OP_SSEL; + val |= !enable << DIRECT_ACCESS_OP_SSEL_SHIFT; + + writel(val, qspi->regs + REG_DIRECT_ACCESS); +} + +static int mchp_coreqspi_setup(struct spi_device *spi) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + /* + * Active low devices need to be specifically set to their inactive + * states during probe. + */ + if (spi->mode & SPI_CS_HIGH) + return 0; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_OP_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + + return 0; +} + static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi) { u32 control, data; @@ -380,19 +419,6 @@ static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi, struct spi_devi return 0; } -static int mchp_coreqspi_setup_op(struct spi_device *spi_dev) -{ - struct spi_controller *ctlr = spi_dev->controller; - struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr); - u32 control = readl_relaxed(qspi->regs + REG_CONTROL); - - control |= (CONTROL_MASTER | CONTROL_ENABLE); - control &= ~CONTROL_CLKIDLE; - writel_relaxed(control, qspi->regs + REG_CONTROL); - - return 0; -} - static inline void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op) { u32 idle_cycles = 0; @@ -483,6 +509,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o reinit_completion(&qspi->data_completion); mchp_coreqspi_config_op(qspi, op); + mchp_coreqspi_set_cs(mem->spi, true); if (op->cmd.opcode) { qspi->txbuf = &opcode; qspi->rxbuf = NULL; @@ -523,6 +550,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o err = -ETIMEDOUT; error: + mchp_coreqspi_set_cs(mem->spi, false); mutex_unlock(&qspi->op_lock); mchp_coreqspi_disable_ints(qspi); @@ -686,6 +714,7 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; int ret; + u32 num_cs, val; ctlr = devm_spi_alloc_host(&pdev->dev, sizeof(*qspi)); if (!ctlr) @@ -718,10 +747,18 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) return ret; } + /* + * The IP core only has a single CS, any more have to be provided via + * gpios + */ + if (of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs)) + num_cs = 1; + + ctlr->num_chipselect = num_cs; + ctlr->bits_per_word_mask = SPI_BPW_MASK(8); ctlr->mem_ops = &mchp_coreqspi_mem_ops; ctlr->mem_caps = &mchp_coreqspi_mem_caps; - ctlr->setup = mchp_coreqspi_setup_op; ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD; ctlr->dev.of_node = np; @@ -729,9 +766,21 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) ctlr->prepare_message = mchp_coreqspi_prepare_message; ctlr->unprepare_message = mchp_coreqspi_unprepare_message; ctlr->transfer_one = mchp_coreqspi_transfer_one; - ctlr->num_chipselect = 2; + ctlr->setup = mchp_coreqspi_setup; + ctlr->set_cs = mchp_coreqspi_set_cs; ctlr->use_gpio_descriptors = true; + val = readl_relaxed(qspi->regs + REG_CONTROL); + val |= (CONTROL_MASTER | CONTROL_ENABLE); + writel_relaxed(val, qspi->regs + REG_CONTROL); + + /* + * Put cs into software controlled mode + */ + val = readl_relaxed(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_EN_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + ret = spi_register_controller(ctlr); if (ret) return dev_err_probe(&pdev->dev, ret, -- cgit 1.3-korg
998f43196d73spi: microchip-core-qspi: control built-in cs manually
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gitConor DooleyApr 30, 2026via nvd-ref
1 file changed · +64 −16
drivers/spi/spi-microchip-core-qspi.c+64 −16 modifieddiff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c index 6b7d350dd53d83..70215a407b5a32 100644 --- a/drivers/spi/spi-microchip-core-qspi.c +++ b/drivers/spi/spi-microchip-core-qspi.c @@ -74,6 +74,13 @@ #define STATUS_FLAGSX4 BIT(8) #define STATUS_MASK GENMASK(8, 0) +/* + * QSPI Direct Access register defines + */ +#define DIRECT_ACCESS_EN_SSEL BIT(0) +#define DIRECT_ACCESS_OP_SSEL BIT(1) +#define DIRECT_ACCESS_OP_SSEL_SHIFT 1 + #define BYTESUPPER_MASK GENMASK(31, 16) #define BYTESLOWER_MASK GENMASK(15, 0) @@ -158,6 +165,38 @@ static int mchp_coreqspi_set_mode(struct mchp_coreqspi *qspi, const struct spi_m return 0; } +static void mchp_coreqspi_set_cs(struct spi_device *spi, bool enable) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + + val &= ~DIRECT_ACCESS_OP_SSEL; + val |= !enable << DIRECT_ACCESS_OP_SSEL_SHIFT; + + writel(val, qspi->regs + REG_DIRECT_ACCESS); +} + +static int mchp_coreqspi_setup(struct spi_device *spi) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + /* + * Active low devices need to be specifically set to their inactive + * states during probe. + */ + if (spi->mode & SPI_CS_HIGH) + return 0; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_OP_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + + return 0; +} + static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi) { u32 control, data; @@ -380,19 +419,6 @@ static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi, struct spi_devi return 0; } -static int mchp_coreqspi_setup_op(struct spi_device *spi_dev) -{ - struct spi_controller *ctlr = spi_dev->controller; - struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr); - u32 control = readl_relaxed(qspi->regs + REG_CONTROL); - - control |= (CONTROL_MASTER | CONTROL_ENABLE); - control &= ~CONTROL_CLKIDLE; - writel_relaxed(control, qspi->regs + REG_CONTROL); - - return 0; -} - static inline void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op) { u32 idle_cycles = 0; @@ -483,6 +509,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o reinit_completion(&qspi->data_completion); mchp_coreqspi_config_op(qspi, op); + mchp_coreqspi_set_cs(mem->spi, true); if (op->cmd.opcode) { qspi->txbuf = &opcode; qspi->rxbuf = NULL; @@ -523,6 +550,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o err = -ETIMEDOUT; error: + mchp_coreqspi_set_cs(mem->spi, false); mutex_unlock(&qspi->op_lock); mchp_coreqspi_disable_ints(qspi); @@ -696,6 +724,7 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; int ret; + u32 num_cs, val; ctlr = devm_spi_alloc_host(&pdev->dev, sizeof(*qspi)); if (!ctlr) @@ -728,10 +757,18 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) return ret; } + /* + * The IP core only has a single CS, any more have to be provided via + * gpios + */ + if (of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs)) + num_cs = 1; + + ctlr->num_chipselect = num_cs; + ctlr->bits_per_word_mask = SPI_BPW_MASK(8); ctlr->mem_ops = &mchp_coreqspi_mem_ops; ctlr->mem_caps = &mchp_coreqspi_mem_caps; - ctlr->setup = mchp_coreqspi_setup_op; ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD; ctlr->dev.of_node = np; @@ -739,9 +776,21 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) ctlr->prepare_message = mchp_coreqspi_prepare_message; ctlr->unprepare_message = mchp_coreqspi_unprepare_message; ctlr->transfer_one = mchp_coreqspi_transfer_one; - ctlr->num_chipselect = 2; + ctlr->setup = mchp_coreqspi_setup; + ctlr->set_cs = mchp_coreqspi_set_cs; ctlr->use_gpio_descriptors = true; + val = readl_relaxed(qspi->regs + REG_CONTROL); + val |= (CONTROL_MASTER | CONTROL_ENABLE); + writel_relaxed(val, qspi->regs + REG_CONTROL); + + /* + * Put cs into software controlled mode + */ + val = readl_relaxed(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_EN_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + ret = spi_register_controller(ctlr); if (ret) return dev_err_probe(&pdev->dev, ret, -- cgit 1.3-korg
ee3c99aa1022spi: microchip-core-qspi: control built-in cs manually
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gitConor DooleyApr 30, 2026via nvd-ref
1 file changed · +64 −16
drivers/spi/spi-microchip-core-qspi.c+64 −16 modifieddiff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c index 6b7d350dd53d83..70215a407b5a32 100644 --- a/drivers/spi/spi-microchip-core-qspi.c +++ b/drivers/spi/spi-microchip-core-qspi.c @@ -74,6 +74,13 @@ #define STATUS_FLAGSX4 BIT(8) #define STATUS_MASK GENMASK(8, 0) +/* + * QSPI Direct Access register defines + */ +#define DIRECT_ACCESS_EN_SSEL BIT(0) +#define DIRECT_ACCESS_OP_SSEL BIT(1) +#define DIRECT_ACCESS_OP_SSEL_SHIFT 1 + #define BYTESUPPER_MASK GENMASK(31, 16) #define BYTESLOWER_MASK GENMASK(15, 0) @@ -158,6 +165,38 @@ static int mchp_coreqspi_set_mode(struct mchp_coreqspi *qspi, const struct spi_m return 0; } +static void mchp_coreqspi_set_cs(struct spi_device *spi, bool enable) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + + val &= ~DIRECT_ACCESS_OP_SSEL; + val |= !enable << DIRECT_ACCESS_OP_SSEL_SHIFT; + + writel(val, qspi->regs + REG_DIRECT_ACCESS); +} + +static int mchp_coreqspi_setup(struct spi_device *spi) +{ + struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller); + u32 val; + + /* + * Active low devices need to be specifically set to their inactive + * states during probe. + */ + if (spi->mode & SPI_CS_HIGH) + return 0; + + val = readl(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_OP_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + + return 0; +} + static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi) { u32 control, data; @@ -380,19 +419,6 @@ static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi, struct spi_devi return 0; } -static int mchp_coreqspi_setup_op(struct spi_device *spi_dev) -{ - struct spi_controller *ctlr = spi_dev->controller; - struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr); - u32 control = readl_relaxed(qspi->regs + REG_CONTROL); - - control |= (CONTROL_MASTER | CONTROL_ENABLE); - control &= ~CONTROL_CLKIDLE; - writel_relaxed(control, qspi->regs + REG_CONTROL); - - return 0; -} - static inline void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op) { u32 idle_cycles = 0; @@ -483,6 +509,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o reinit_completion(&qspi->data_completion); mchp_coreqspi_config_op(qspi, op); + mchp_coreqspi_set_cs(mem->spi, true); if (op->cmd.opcode) { qspi->txbuf = &opcode; qspi->rxbuf = NULL; @@ -523,6 +550,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o err = -ETIMEDOUT; error: + mchp_coreqspi_set_cs(mem->spi, false); mutex_unlock(&qspi->op_lock); mchp_coreqspi_disable_ints(qspi); @@ -696,6 +724,7 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; int ret; + u32 num_cs, val; ctlr = devm_spi_alloc_host(&pdev->dev, sizeof(*qspi)); if (!ctlr) @@ -728,10 +757,18 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) return ret; } + /* + * The IP core only has a single CS, any more have to be provided via + * gpios + */ + if (of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs)) + num_cs = 1; + + ctlr->num_chipselect = num_cs; + ctlr->bits_per_word_mask = SPI_BPW_MASK(8); ctlr->mem_ops = &mchp_coreqspi_mem_ops; ctlr->mem_caps = &mchp_coreqspi_mem_caps; - ctlr->setup = mchp_coreqspi_setup_op; ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD; ctlr->dev.of_node = np; @@ -739,9 +776,21 @@ static int mchp_coreqspi_probe(struct platform_device *pdev) ctlr->prepare_message = mchp_coreqspi_prepare_message; ctlr->unprepare_message = mchp_coreqspi_unprepare_message; ctlr->transfer_one = mchp_coreqspi_transfer_one; - ctlr->num_chipselect = 2; + ctlr->setup = mchp_coreqspi_setup; + ctlr->set_cs = mchp_coreqspi_set_cs; ctlr->use_gpio_descriptors = true; + val = readl_relaxed(qspi->regs + REG_CONTROL); + val |= (CONTROL_MASTER | CONTROL_ENABLE); + writel_relaxed(val, qspi->regs + REG_CONTROL); + + /* + * Put cs into software controlled mode + */ + val = readl_relaxed(qspi->regs + REG_DIRECT_ACCESS); + val |= DIRECT_ACCESS_EN_SSEL; + writel(val, qspi->regs + REG_DIRECT_ACCESS); + ret = spi_register_controller(ctlr); if (ret) return dev_err_probe(&pdev->dev, ret, -- cgit 1.3-korg
Vulnerability mechanics
Root cause
"The built-in chip select of the Microchip coreQSPI controller was left in hardware-automated mode, causing it to be asserted during transfers to other (GPIO-based) devices, leading to bus contention."
Attack vector
An attacker who can trigger SPI transfers to a device attached via a GPIO chip select while the built-in chip select is still in hardware-automated mode will observe the built-in CS being asserted low during the GPIO device's access. This happens because the hardware automatically drives the built-in CS low whenever any data is written to the transmit buffer, regardless of which device is being addressed. The result is that the built-in CS line is held low while Linux tries to access the GPIO-attached device, causing bus contention or incorrect device selection. No special network path is required — the precondition is simply that two or more SPI devices are connected to the controller and at least one uses the built-in CS while another uses a GPIO CS.
Affected code
The vulnerability is in the Microchip coreQSPI driver (`drivers/spi/spi-microchip-core-qspi.c`). The built-in chip select was left in hardware-automated mode, where it is asserted low when the transmit buffer is written and de-asserted high after the programmed number of bytes are sent. No software-controlled `set_cs` callback existed, so the driver could not coordinate the built-in CS with GPIO-based CS lines used for additional devices.
What the fix does
The patch switches the built-in chip select from hardware-automated to software-controlled mode by setting `DIRECT_ACCESS_EN_SSEL` in the `REG_DIRECT_ACCESS` register at probe time. It adds a new `mchp_coreqspi_set_cs` callback that writes the `DIRECT_ACCESS_OP_SSEL` bit to assert or de-assert the CS under software control. For `mem_ops` transfers, `mchp_coreqspi_set_cs` is called explicitly at the start and end of `mchp_coreqspi_exec_op`. The old `mchp_coreqspi_setup_op` callback, which modified `CONTROL_CLKIDLE` per-device (unsafe with multiple devices), is removed; `CONTROL_MASTER` and `CONTROL_ENABLE` are now set once during probe. The `num_chipselect` is also changed from a hardcoded `2` to a value read from the device tree, defaulting to `1`.
Preconditions
- configTwo or more SPI devices must be attached to the Microchip coreQSPI controller, with at least one using the built-in chip select and at least one using a GPIO chip select.
- configThe built-in chip select must be left in its default hardware-automated mode (no software CS control).
Generated on May 28, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
3News mentions
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