On 01/24/2016 08:09 PM, Yao Yuan wrote:
On 01/25/2016 04:16 AM, York Sun wrote:
On 01/22/2016 07:43 AM, Scott Wood wrote:
On 01/21/2016 09:35 PM, Qianyu Gong wrote:
-----Original Message----- From: Scott Wood Sent: Friday, January 22, 2016 3:30 AM To: Qianyu Gong qianyu.gong@nxp.com; u-boot@lists.denx.de; R58495@freescale.com Cc: Mingkai.Hu@freescale.com; jteki@openedev.com; B48286@freescale.com; Shaohui.Xie@freescale.com; Wenbin.Song@freescale.com; Scott Wood oss@buserror.net; Gong Qianyu Qianyu.Gong@freescale.com Subject: Re: [Patch V5 2/4] spi: fsl_qspi: Fix qspi_op_rdid memcpy issue
On 01/20/2016 09:43 PM, Gong Qianyu wrote:
From: Gong Qianyu Qianyu.Gong@freescale.com
In current driver everytime we memcpy 4 bytes to the dest memory regardless of the remaining length. This patch adds checking the remaining length before memcpy. If the length is shorter than 4 bytes, memcpy the actual length of data to the dest memory.
Signed-off-by: Gong Qianyu Qianyu.Gong@freescale.com
V2-V5:
- No change.
drivers/spi/fsl_qspi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c index 38e5900..f178857 100644 --- a/drivers/spi/fsl_qspi.c +++ b/drivers/spi/fsl_qspi.c @@ -500,7 +500,10 @@ static void qspi_op_rdid(struct fsl_qspi_priv *priv, u32
*rxbuf, u32 len)
if (rbsr_reg & QSPI_RBSR_RDBFL_MASK) { data = qspi_read32(priv->flags, ®s->rbdr[i]); data = qspi_endian_xchg(data);
memcpy(rxbuf, &data, 4);
if (size < 4)memcpy(rxbuf, &data, size);elsememcpy(rxbuf, &data, 4);memcpy(rxbuf, &data, min(size, 4));
rxbuf++; size -= 4; i++;size -= 4 even if size was < 4?
-Scott
Yes.. The following is complete code:
i = 0; size = len; while ((RX_BUFFER_SIZE >= size) && (size > 0)) { rbsr_reg = qspi_read32(priv->flags, ®s->rbsr); if (rbsr_reg & QSPI_RBSR_RDBFL_MASK) { data = qspi_read32(priv->flags, ®s->rbdr[i]); data = qspi_endian_xchg(data); memcpy(rxbuf, &data, min(size, 4)); rxbuf++; size -= 4; i++; } }I'm not saying it doesn't work (assuming i is signed, which the "complete code" above doesn't show). I'm saying it looks weird, and it would be better to have a variable that holds min(size, 4) and pass that to both memcpy and the subtraction.
Qianyu,
Previously I said it looked weird for doing this. Please fix.
"size" is declared as "int". "len" is declared as u32. That's not "int". If you trace back the functions, you may see it came from DIV_ROUND_UP(bitlen, 8) where bitlen is "unsigned int". So technically the code is safe. But it is _confusing_. We don't want to confuse ourselves when reading the code later. And the fix is easy, isn't it?
York
How about like this?
diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c index feec3e8..13bba09 100644 --- a/drivers/spi/fsl_qspi.c +++ b/drivers/spi/fsl_qspi.c @@ -477,8 +477,8 @@ static void qspi_op_rdbank(struct fsl_qspi_priv *priv, u8 *rxbuf, u32 len) static void qspi_op_rdid(struct fsl_qspi_priv *priv, u32 *rxbuf, u32 len) { struct fsl_qspi_regs *regs = priv->regs;
u32 mcr_reg, rbsr_reg, data;int i, size;
u32 mcr_reg, rbsr_reg, data, size;int i; mcr_reg = qspi_read32(priv->flags, ®s->mcr); qspi_write32(priv->flags, ®s->mcr,@@ -495,14 +495,14 @@ static void qspi_op_rdid(struct fsl_qspi_priv *priv, u32 *rxbuf, u32 len)
i = 0; size = len;
while ((RX_BUFFER_SIZE >= size) && (size > 0)) {
while ((RX_BUFFER_SIZE >= size) && (size != 0)) {
You can keep using "size > 0". It is still correct.
rbsr_reg = qspi_read32(priv->flags, ®s->rbsr); if (rbsr_reg & QSPI_RBSR_RDBFL_MASK) { data = qspi_read32(priv->flags, ®s->rbdr[i]); data = qspi_endian_xchg(data);
memcpy(rxbuf, &data, 4);
memcpy(rxbuf, &data, min(size, 4));size = (size < 4) ? 0 : ( size - 4); rxbuf++;
size -= 4; i++; } }
The rest looks OK to me.
York