[u-boot][PATCH 1/2] spi: atmel-quadspi: fix possible MMIO window size overrun

[Tudor.Ambarus at microchip.com]

From: Tudor Ambarus <tudor.ambarus at microchip.com>

The sama5d2 QSPI controller memory space is limited to 128MB:
0x9000_00000-0x9800_00000/0XD000_0000--0XD800_0000.

There are nor flashes that are bigger in size than the memory size
supported by the controller: Micron MT25QL02G (256 MB).

Check if the address exceeds the MMIO window size. An improvement
would be to add support for regular SPI mode and fall back to it
when the flash memories overrun the controller's memory space.

Fixes: 24c8ff4684c5 ("spi: Add Atmel QuadSPI driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus at microchip.com>
---
 drivers/spi/atmel-quadspi.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
index a09bf884e837..4099ee87993d 100644
--- a/drivers/spi/atmel-quadspi.c
+++ b/drivers/spi/atmel-quadspi.c
@@ -146,6 +146,7 @@ struct atmel_qspi_caps {
 struct atmel_qspi {
 	void __iomem *regs;
 	void __iomem *mem;
+	resource_size_t mmap_size;
 	const struct atmel_qspi_caps *caps;
 	ulong bus_clk_rate;
 	u32 mr;
@@ -326,6 +327,14 @@ static int atmel_qspi_exec_op(struct spi_slave *slave,
 	u32 sr, imr, offset;
 	int err;
 
+	/*
+	 * Check if the address exceeds the MMIO window size. An improvement
+	 * would be to add support for regular SPI mode and fall back to it
+	 * when the flash memories overrun the controller's memory space.
+	 */
+	if (op->addr.val + op->data.nbytes > aq->mmap_size)
+		return -ENOTSUPP;
+
 	err = atmel_qspi_set_cfg(aq, op, &offset);
 	if (err)
 		return err;
@@ -490,6 +499,8 @@ static int atmel_qspi_probe(struct udevice *dev)
 	if (IS_ERR(aq->mem))
 		return PTR_ERR(aq->mem);
 
+	aq->mmap_size = resource_size(&res);
+
 	ret = atmel_qspi_enable_clk(dev);
 	if (ret)
 		return ret;
-- 
2.23.0