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[Qemu-devel] [PATCH v2] i2c: Add asserts for second smbus i2c_start_tran
From: |
minyard |
Subject: |
[Qemu-devel] [PATCH v2] i2c: Add asserts for second smbus i2c_start_transfer() |
Date: |
Mon, 24 Oct 2016 10:42:33 -0500 |
From: Corey Minyard <address@hidden>
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 <address@hidden>
---
hw/i2c/core.c | 7 ++++++-
hw/i2c/smbus.c | 12 +++++++++---
2 files changed, 15 insertions(+), 4 deletions(-)
Changes since v1:
* Fixed the comments, I should have run it through checkpatch.
* Fixed the asserts to avoid side effects.
diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index bd8f167..abd4c4c 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 3979b3d..5b4dd3e 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;
--
2.7.4
- [Qemu-devel] [PATCH v2] i2c: Add asserts for second smbus i2c_start_transfer(),
minyard <=