nvmem: core: fix read buffer in place (2fe518fe) · Commits · 戴 / test

When the bit_offset in the cell is zero, the pointer to the msb will not be properly initialized (ie, will still be pointing to the first byte in the buffer). This being the case, if there are bits to clear in the msb, those will be left untouched while the mask will incorrectly clear bit positions on the first byte. This commit also makes sure that any byte unused in the cell is cleared. Signed-off-by:

Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org> Signed-off-by:

Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/core.c

+10 −5

Original line number	Diff line number	Diff line
		@@ -1166,7 +1166,7 @@ EXPORT_SYMBOL_GPL(nvmem_cell_put);
		static void nvmem_shift_read_buffer_in_place(struct nvmem_cell cell, void buf)
		{
		u8 p, b;
		int i, bit_offset = cell->bit_offset;
		int i, extra, bit_offset = cell->bit_offset;

		p = b = buf;
		if (bit_offset) {
		@@ -1181,11 +1181,16 @@ static void nvmem_shift_read_buffer_in_place(struct nvmem_cell cell, void buf)
		p = b;
		*b++ >>= bit_offset;
		}
		} else {
		/* point to the msb */
		p += cell->bytes - 1;
		}

		/* result fits in less bytes */
		if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
		extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
		while (--extra >= 0)
		*p-- = 0;
		}

		/* clear msb bits if any leftover in the last byte */
		*p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
		}

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