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Posted to commits@nuttx.apache.org by GitBox <gi...@apache.org> on 2021/01/17 22:32:26 UTC
[GitHub] [incubator-nuttx] v01d commented on a change in pull request #2705: nrf52: Add a static copy buffer for i2c NOSTART transfers
v01d commented on a change in pull request #2705:
URL: https://github.com/apache/incubator-nuttx/pull/2705#discussion_r559248318
##########
File path: arch/arm/src/nrf52/nrf52_i2c.c
##########
@@ -308,11 +313,20 @@ static int nrf52_i2c_transfer(FAR struct i2c_master_s *dev,
/* Combine buffers */
- pack_buf = kmm_malloc(priv->msgv[0].length +
- priv->msgv[1].length);
- if (pack_buf == NULL)
+ if ((priv->msgv[0].length +
+ priv->msgv[1].length) <=
+ CONFIG_NRF52_I2C_MASTER_COPY_BUF_SIZE)
+ {
+ pack_buf = (uint8_t *)priv->copy_buf;
+ }
+ else
{
- return -1;
+ pack_buf = kmm_malloc(priv->msgv[0].length +
+ priv->msgv[1].length);
+ if (pack_buf == NULL)
+ {
+ return -1;
Review comment:
maybe better -ENOMEM?
##########
File path: arch/arm/src/nrf52/Kconfig
##########
@@ -633,4 +633,16 @@ config NRF52_I2C_MASTER_DISABLE_NOSTART
bool "Disable the I2C Master NOSTART flag support"
default n
+config NRF52_I2C_MASTER_COPY_BUF_SIZE
+ int "Static buffer size for NOSTART flag support"
+ depends on !NRF52_I2C_MASTER_DISABLE_NOSTART
+ default 4
+ ---help---
+ To combine two i2c messages that are part of a
+ single transaction (NO_STOP-NO_START) the nrf52
+ hardware requires these be joined into a single
+ transfer. This static buffer will be used if the
+ transaction will fit otherwise it will fall back
+ on malloc.
Review comment:
Could you move part of this explanation to `NRF52_I2C_MASTER_DISABLE_NOSTART` (to explain why this option exists)?
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