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authorCorey Minyard <cminyard@mvista.com>2016-10-24 10:42:33 -0500
committerPeter Maydell <peter.maydell@linaro.org>2016-10-24 16:48:02 +0100
commitcc083d8a25e0a886c3cd4bea0bf57ac4e896fa3f (patch)
treef19623fb6ecd678d87d0cbd769ba8d979aeace2a
parent19a6e31c9d2701ef648b70ddcfc3bf64cec8c37e (diff)
downloadqemu-arm-cc083d8a25e0a886c3cd4bea0bf57ac4e896fa3f.tar.gz
i2c: Add asserts for second smbus i2c_start_transfer()pull-target-arm-20161024
Some SMBus operations restart the transfer to convert from write to read mode without an intervening i2c_end_transfer(). The second call cannot fail, so the return code is unchecked, but this causes Coverity to complain. So add some asserts and documentation about this. Signed-off-by: Corey Minyard <cminyard@mvista.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r--hw/i2c/core.c7
-rw-r--r--hw/i2c/smbus.c12
2 files changed, 15 insertions, 4 deletions
diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index bd8f16759d..abd4c4cddb 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -88,7 +88,12 @@ int i2c_bus_busy(I2CBus *bus)
return !QLIST_EMPTY(&bus->current_devs);
}
-/* Returns non-zero if the address is not valid. */
+/*
+ * Returns non-zero if the address is not valid. If this is called
+ * again without an intervening i2c_end_transfer(), like in the SMBus
+ * case where the operation is switched from write to read, this
+ * function will not rescan the bus and thus cannot fail.
+ */
/* TODO: Make this handle multiple masters. */
int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
{
diff --git a/hw/i2c/smbus.c b/hw/i2c/smbus.c
index 3979b3dad7..5b4dd3eba4 100644
--- a/hw/i2c/smbus.c
+++ b/hw/i2c/smbus.c
@@ -248,7 +248,9 @@ int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command)
return -1;
}
i2c_send(bus, command);
- i2c_start_transfer(bus, addr, 1);
+ if (i2c_start_transfer(bus, addr, 1)) {
+ assert(0);
+ }
data = i2c_recv(bus);
i2c_nack(bus);
i2c_end_transfer(bus);
@@ -273,7 +275,9 @@ int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command)
return -1;
}
i2c_send(bus, command);
- i2c_start_transfer(bus, addr, 1);
+ if (i2c_start_transfer(bus, addr, 1)) {
+ assert(0);
+ }
data = i2c_recv(bus);
data |= i2c_recv(bus) << 8;
i2c_nack(bus);
@@ -302,7 +306,9 @@ int smbus_read_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data)
return -1;
}
i2c_send(bus, command);
- i2c_start_transfer(bus, addr, 1);
+ if (i2c_start_transfer(bus, addr, 1)) {
+ assert(0);
+ }
len = i2c_recv(bus);
if (len > 32) {
len = 0;