static void cqspi_chipselect(struct spi_nor *nor)
{
	struct cqspi_flash_pdata *f_pdata = nor->priv;
	struct cqspi_st *cqspi = f_pdata->cqspi;
	void __iomem *reg_base = cqspi->iobase;
	unsigned int chip_select = f_pdata->cs;
	unsigned int reg;

	reg = readl(reg_base + CQSPI_REG_CONFIG);
	if (cqspi->is_decoded_cs) {
		reg |= CQSPI_REG_CONFIG_DECODE_MASK;
	} else {
		reg &= ~CQSPI_REG_CONFIG_DECODE_MASK;

		/* Convert CS if without decoder.
		 * CS0 to 4b'1110
		 * CS1 to 4b'1101
		 * CS2 to 4b'1011
		 * CS3 to 4b'0111
		 */
		chip_select = 0xF & ~(1 << chip_select);
	}

	reg &= ~(CQSPI_REG_CONFIG_CHIPSELECT_MASK
		 << CQSPI_REG_CONFIG_CHIPSELECT_LSB);
	reg |= (chip_select & CQSPI_REG_CONFIG_CHIPSELECT_MASK)
	    << CQSPI_REG_CONFIG_CHIPSELECT_LSB;
	writel(reg, reg_base + CQSPI_REG_CONFIG);
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.