From ca2abb75a086d8b0bdb51689f331ba8f1a146379 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Sat, 18 May 2019 11:59:54 -0600 Subject: [PATCH] spi: Avoid using malloc() in a critical function In general we should avoid calling malloc() and free() repeatedly in U-Boot lest we turn it into tianocore. In SPL this can make SPI flash unusable since free() is often a nop and allocation space is limited. In any case, these seems no need for malloc() since the number of bytes is very small, perhaps less than 8. Signed-off-by: Simon Glass Fixes: d13f5b254a (spi: Extend the core to ease integration of SPI memory controllers) --- drivers/spi/spi-mem.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c index b86eee75bc..7aabebeff5 100644 --- a/drivers/spi/spi-mem.c +++ b/drivers/spi/spi-mem.c @@ -201,7 +201,6 @@ int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op) unsigned int pos = 0; const u8 *tx_buf = NULL; u8 *rx_buf = NULL; - u8 *op_buf; int op_len; u32 flag; int ret; @@ -338,7 +337,17 @@ int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op) } op_len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes; - op_buf = calloc(1, op_len); + + /* + * Avoid using malloc() here so that we can use this code in SPL where + * simple malloc may be used. That implementation does not allow free() + * so repeated calls to this code can exhaust the space. + * + * The value of op_len is small, since it does not include the actual + * data being sent, only the op-code and address. In fact, it should be + * possible to just use a small fixed value here instead of op_len. + */ + u8 op_buf[op_len]; op_buf[pos++] = op->cmd.opcode; @@ -382,8 +391,6 @@ int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op) debug("%02x ", tx_buf ? tx_buf[i] : rx_buf[i]); debug("[ret %d]\n", ret); - free(op_buf); - if (ret < 0) return ret; #endif /* __UBOOT__ */