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authorCorey Minyard <cminyard@mvista.com>2017-01-09 11:40:20 +0000
committerPeter Maydell <peter.maydell@linaro.org>2017-01-09 11:40:20 +0000
commitd307c28ca9dba7a0677035c9244198b05164c873 (patch)
treeee942307fac668f7a2d531bf6b86e6db025cdfd0
parentffe22bf51065dd33022cf91f77a821d1f11c250d (diff)
downloadqemu-arm-d307c28ca9dba7a0677035c9244198b05164c873.tar.gz
i2c: Allow I2C devices to NAK start events
Add a return value to the event handler. Some I2C devices will NAK if they have no data, so allow them to do this. This required the following changes: Go through all the event handlers and change them to return int and return 0. Modify i2c_start_transfer to terminate the transaction on a NAK. Modify smbus handing to not assert if a NAK occurs on a second operation, and terminate the transaction and return -1 instead. Add some information on semantics to I2CSlaveClass. 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/arm/pxa2xx.c4
-rw-r--r--hw/arm/tosa.c4
-rw-r--r--hw/arm/z2.c4
-rw-r--r--hw/audio/wm8750.c4
-rw-r--r--hw/display/ssd0303.c4
-rw-r--r--hw/gpio/max7310.c4
-rw-r--r--hw/i2c/core.c31
-rw-r--r--hw/i2c/i2c-ddc.c4
-rw-r--r--hw/i2c/smbus.c13
-rw-r--r--hw/input/lm832x.c4
-rw-r--r--hw/misc/tmp105.c3
-rw-r--r--hw/timer/ds1338.c4
-rw-r--r--hw/timer/twl92230.c4
-rw-r--r--include/hw/i2c/i2c.h16
14 files changed, 78 insertions, 25 deletions
diff --git a/hw/arm/pxa2xx.c b/hw/arm/pxa2xx.c
index bdcf6bcce7..d31b4577f0 100644
--- a/hw/arm/pxa2xx.c
+++ b/hw/arm/pxa2xx.c
@@ -1258,7 +1258,7 @@ static void pxa2xx_i2c_update(PXA2xxI2CState *s)
}
/* These are only stubs now. */
-static void pxa2xx_i2c_event(I2CSlave *i2c, enum i2c_event event)
+static int pxa2xx_i2c_event(I2CSlave *i2c, enum i2c_event event)
{
PXA2xxI2CSlaveState *slave = PXA2XX_I2C_SLAVE(i2c);
PXA2xxI2CState *s = slave->host;
@@ -1280,6 +1280,8 @@ static void pxa2xx_i2c_event(I2CSlave *i2c, enum i2c_event event)
break;
}
pxa2xx_i2c_update(s);
+
+ return 0;
}
static int pxa2xx_i2c_rx(I2CSlave *i2c)
diff --git a/hw/arm/tosa.c b/hw/arm/tosa.c
index 39d9dbbae6..c3db996930 100644
--- a/hw/arm/tosa.c
+++ b/hw/arm/tosa.c
@@ -172,7 +172,7 @@ static int tosa_dac_send(I2CSlave *i2c, uint8_t data)
return 0;
}
-static void tosa_dac_event(I2CSlave *i2c, enum i2c_event event)
+static int tosa_dac_event(I2CSlave *i2c, enum i2c_event event)
{
TosaDACState *s = TOSA_DAC(i2c);
@@ -194,6 +194,8 @@ static void tosa_dac_event(I2CSlave *i2c, enum i2c_event event)
default:
break;
}
+
+ return 0;
}
static int tosa_dac_recv(I2CSlave *s)
diff --git a/hw/arm/z2.c b/hw/arm/z2.c
index b3a6bbd210..1607cbdb03 100644
--- a/hw/arm/z2.c
+++ b/hw/arm/z2.c
@@ -220,7 +220,7 @@ static int aer915_send(I2CSlave *i2c, uint8_t data)
return 0;
}
-static void aer915_event(I2CSlave *i2c, enum i2c_event event)
+static int aer915_event(I2CSlave *i2c, enum i2c_event event)
{
AER915State *s = AER915(i2c);
@@ -238,6 +238,8 @@ static void aer915_event(I2CSlave *i2c, enum i2c_event event)
default:
break;
}
+
+ return 0;
}
static int aer915_recv(I2CSlave *slave)
diff --git a/hw/audio/wm8750.c b/hw/audio/wm8750.c
index 0c6500e96a..f8b5bebfc2 100644
--- a/hw/audio/wm8750.c
+++ b/hw/audio/wm8750.c
@@ -303,7 +303,7 @@ static void wm8750_reset(I2CSlave *i2c)
s->i2c_len = 0;
}
-static void wm8750_event(I2CSlave *i2c, enum i2c_event event)
+static int wm8750_event(I2CSlave *i2c, enum i2c_event event)
{
WM8750State *s = WM8750(i2c);
@@ -321,6 +321,8 @@ static void wm8750_event(I2CSlave *i2c, enum i2c_event event)
default:
break;
}
+
+ return 0;
}
#define WM8750_LINVOL 0x00
diff --git a/hw/display/ssd0303.c b/hw/display/ssd0303.c
index d3017563f3..68a80b9d64 100644
--- a/hw/display/ssd0303.c
+++ b/hw/display/ssd0303.c
@@ -179,7 +179,7 @@ static int ssd0303_send(I2CSlave *i2c, uint8_t data)
return 0;
}
-static void ssd0303_event(I2CSlave *i2c, enum i2c_event event)
+static int ssd0303_event(I2CSlave *i2c, enum i2c_event event)
{
ssd0303_state *s = SSD0303(i2c);
@@ -193,6 +193,8 @@ static void ssd0303_event(I2CSlave *i2c, enum i2c_event event)
/* Nothing to do. */
break;
}
+
+ return 0;
}
static void ssd0303_update_display(void *opaque)
diff --git a/hw/gpio/max7310.c b/hw/gpio/max7310.c
index 1bd5eaf911..f82e3e6555 100644
--- a/hw/gpio/max7310.c
+++ b/hw/gpio/max7310.c
@@ -129,7 +129,7 @@ static int max7310_tx(I2CSlave *i2c, uint8_t data)
return 0;
}
-static void max7310_event(I2CSlave *i2c, enum i2c_event event)
+static int max7310_event(I2CSlave *i2c, enum i2c_event event)
{
MAX7310State *s = MAX7310(i2c);
s->len = 0;
@@ -147,6 +147,8 @@ static void max7310_event(I2CSlave *i2c, enum i2c_event event)
default:
break;
}
+
+ return 0;
}
static const VMStateDescription vmstate_max7310 = {
diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index e40781ea3b..2c1234cdff 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -88,18 +88,26 @@ int i2c_bus_busy(I2CBus *bus)
return !QLIST_EMPTY(&bus->current_devs);
}
+/* TODO: Make this handle multiple masters. */
/*
- * 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.
+ * Start or continue an i2c transaction. When this is called for the
+ * first time or after an i2c_end_transfer(), if it returns an error
+ * the bus transaction is terminated (or really never started). If
+ * this is called after another i2c_start_transfer() without an
+ * intervening i2c_end_transfer(), and it returns an error, the
+ * transaction will not be terminated. The caller must do it.
+ *
+ * This corresponds with the way real hardware works. The SMBus
+ * protocol uses a start transfer to switch from write to read mode
+ * without releasing the bus. If that fails, the bus is still
+ * in a transaction.
*/
-/* TODO: Make this handle multiple masters. */
int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
{
BusChild *kid;
I2CSlaveClass *sc;
I2CNode *node;
+ bool bus_scanned = false;
if (address == I2C_BROADCAST) {
/*
@@ -130,6 +138,7 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
}
}
}
+ bus_scanned = true;
}
if (QLIST_EMPTY(&bus->current_devs)) {
@@ -137,11 +146,21 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
}
QLIST_FOREACH(node, &bus->current_devs, next) {
+ int rv;
+
sc = I2C_SLAVE_GET_CLASS(node->elt);
/* If the bus is already busy, assume this is a repeated
start condition. */
+
if (sc->event) {
- sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND);
+ rv = sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND);
+ if (rv && !bus->broadcast) {
+ if (bus_scanned) {
+ /* First call, terminate the transfer. */
+ i2c_end_transfer(bus);
+ }
+ return rv;
+ }
}
}
return 0;
diff --git a/hw/i2c/i2c-ddc.c b/hw/i2c/i2c-ddc.c
index 1227212934..66899d7233 100644
--- a/hw/i2c/i2c-ddc.c
+++ b/hw/i2c/i2c-ddc.c
@@ -230,13 +230,15 @@ static void i2c_ddc_reset(DeviceState *ds)
s->reg = 0;
}
-static void i2c_ddc_event(I2CSlave *i2c, enum i2c_event event)
+static int i2c_ddc_event(I2CSlave *i2c, enum i2c_event event)
{
I2CDDCState *s = I2CDDC(i2c);
if (event == I2C_START_SEND) {
s->firstbyte = true;
}
+
+ return 0;
}
static int i2c_ddc_rx(I2CSlave *i2c)
diff --git a/hw/i2c/smbus.c b/hw/i2c/smbus.c
index 5b4dd3eba4..2d1b79a689 100644
--- a/hw/i2c/smbus.c
+++ b/hw/i2c/smbus.c
@@ -67,7 +67,7 @@ static void smbus_do_write(SMBusDevice *dev)
}
}
-static void smbus_i2c_event(I2CSlave *s, enum i2c_event event)
+static int smbus_i2c_event(I2CSlave *s, enum i2c_event event)
{
SMBusDevice *dev = SMBUS_DEVICE(s);
@@ -148,6 +148,8 @@ static void smbus_i2c_event(I2CSlave *s, enum i2c_event event)
break;
}
}
+
+ return 0;
}
static int smbus_i2c_recv(I2CSlave *s)
@@ -249,7 +251,8 @@ int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command)
}
i2c_send(bus, command);
if (i2c_start_transfer(bus, addr, 1)) {
- assert(0);
+ i2c_end_transfer(bus);
+ return -1;
}
data = i2c_recv(bus);
i2c_nack(bus);
@@ -276,7 +279,8 @@ int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command)
}
i2c_send(bus, command);
if (i2c_start_transfer(bus, addr, 1)) {
- assert(0);
+ i2c_end_transfer(bus);
+ return -1;
}
data = i2c_recv(bus);
data |= i2c_recv(bus) << 8;
@@ -307,7 +311,8 @@ int smbus_read_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data)
}
i2c_send(bus, command);
if (i2c_start_transfer(bus, addr, 1)) {
- assert(0);
+ i2c_end_transfer(bus);
+ return -1;
}
len = i2c_recv(bus);
if (len > 32) {
diff --git a/hw/input/lm832x.c b/hw/input/lm832x.c
index 539682cac8..2340523da0 100644
--- a/hw/input/lm832x.c
+++ b/hw/input/lm832x.c
@@ -383,7 +383,7 @@ static void lm_kbd_write(LM823KbdState *s, int reg, int byte, uint8_t value)
}
}
-static void lm_i2c_event(I2CSlave *i2c, enum i2c_event event)
+static int lm_i2c_event(I2CSlave *i2c, enum i2c_event event)
{
LM823KbdState *s = LM8323(i2c);
@@ -397,6 +397,8 @@ static void lm_i2c_event(I2CSlave *i2c, enum i2c_event event)
default:
break;
}
+
+ return 0;
}
static int lm_i2c_rx(I2CSlave *i2c)
diff --git a/hw/misc/tmp105.c b/hw/misc/tmp105.c
index f5c2472b5b..04e83787d4 100644
--- a/hw/misc/tmp105.c
+++ b/hw/misc/tmp105.c
@@ -176,7 +176,7 @@ static int tmp105_tx(I2CSlave *i2c, uint8_t data)
return 0;
}
-static void tmp105_event(I2CSlave *i2c, enum i2c_event event)
+static int tmp105_event(I2CSlave *i2c, enum i2c_event event)
{
TMP105State *s = TMP105(i2c);
@@ -185,6 +185,7 @@ static void tmp105_event(I2CSlave *i2c, enum i2c_event event)
}
s->len = 0;
+ return 0;
}
static int tmp105_post_load(void *opaque, int version_id)
diff --git a/hw/timer/ds1338.c b/hw/timer/ds1338.c
index f5d04dd5d7..3849b74a68 100644
--- a/hw/timer/ds1338.c
+++ b/hw/timer/ds1338.c
@@ -94,7 +94,7 @@ static void inc_regptr(DS1338State *s)
}
}
-static void ds1338_event(I2CSlave *i2c, enum i2c_event event)
+static int ds1338_event(I2CSlave *i2c, enum i2c_event event)
{
DS1338State *s = DS1338(i2c);
@@ -113,6 +113,8 @@ static void ds1338_event(I2CSlave *i2c, enum i2c_event event)
default:
break;
}
+
+ return 0;
}
static int ds1338_recv(I2CSlave *i2c)
diff --git a/hw/timer/twl92230.c b/hw/timer/twl92230.c
index 7ba4e9a7c9..b8d914e49b 100644
--- a/hw/timer/twl92230.c
+++ b/hw/timer/twl92230.c
@@ -713,12 +713,14 @@ static void menelaus_write(void *opaque, uint8_t addr, uint8_t value)
}
}
-static void menelaus_event(I2CSlave *i2c, enum i2c_event event)
+static int menelaus_event(I2CSlave *i2c, enum i2c_event event)
{
MenelausState *s = TWL92230(i2c);
if (event == I2C_START_SEND)
s->firstbyte = 1;
+
+ return 0;
}
static int menelaus_tx(I2CSlave *i2c, uint8_t data)
diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h
index c4085aa366..2ce611d4c8 100644
--- a/include/hw/i2c/i2c.h
+++ b/include/hw/i2c/i2c.h
@@ -32,14 +32,22 @@ typedef struct I2CSlaveClass
/* Callbacks provided by the device. */
int (*init)(I2CSlave *dev);
- /* Master to slave. */
+ /* Master to slave. Returns non-zero for a NAK, 0 for success. */
int (*send)(I2CSlave *s, uint8_t data);
- /* Slave to master. */
+ /*
+ * Slave to master. This cannot fail, the device should always
+ * return something here. Negative values probably result in 0xff
+ * and a possible log from the driver, and shouldn't be used.
+ */
int (*recv)(I2CSlave *s);
- /* Notify the slave of a bus state change. */
- void (*event)(I2CSlave *s, enum i2c_event event);
+ /*
+ * Notify the slave of a bus state change. For start event,
+ * returns non-zero to NAK an operation. For other events the
+ * return code is not used and should be zero.
+ */
+ int (*event)(I2CSlave *s, enum i2c_event event);
} I2CSlaveClass;
struct I2CSlave