[01/19] i2c: Allow I2C devices to NAK start events

Message ID	1483111310-24808-2-git-send-email-minyard@acm.org
State	New
Headers	show Delivered-To: patch@linaro.org Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) client-ip=2001:4830:134:3::11; From: minyard@acm.org To: qemu-devel@nongnu.org Date: Fri, 30 Dec 2016 09:21:32 -0600 Message-Id: <1483111310-24808-2-git-send-email-minyard@acm.org> In-Reply-To: <1483111310-24808-1-git-send-email-minyard@acm.org> References: <1483111310-24808-1-git-send-email-minyard@acm.org> Subject: [Qemu-devel] [PATCH 01/19] i2c: Allow I2C devices to NAK start events Precedence: list Cc: Corey Minyard <cminyard@mvista.com>, minyard@acm.org Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" <qemu-devel-bounces+patch=linaro.org@nongnu.org>

diff --git a/hw/arm/pxa2xx.c b/hw/arm/pxa2xx.c index bdcf6bc..d31b457 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 39d9dbb..c3db996 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 b3a6bbd..1607cbd 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 0c6500e..f8b5beb 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 d301756..68a80b9 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 1bd5eaf..f82e3e6 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 e40781e..2c1234c 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 1227212..66899d7 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 5b4dd3e..2d1b79a 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 539682c..2340523 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 f5c2472..04e8378 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 f5d04dd..3849b74 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 7ba4e9a..b8d914e 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 c4085aa..2ce611d 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

[01/19] i2c: Allow I2C devices to NAK start events

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Patch