From b5e1879de9c347ab03a09d71f12d40aad0a16d6d Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Wed, 12 Sep 2018 14:19:30 -0700 Subject: [PATCH 2/2] aspeed/i2c: Fix receive done interrupt handling The AST2500 datasheet says: I2CD10 Interrupt Status Register bit 2 Receive Done Interrupt status S/W needs to clear this status bit to allow next data receiving The Rx interrrupt done interrupt status bit needs to be cleared explicitly before the next byte can be received, and must therefore not be auto-cleared. Also, receiving the next byte must be delayed until the bit has been cleared. Signed-off-by: Guenter Roeck --- hw/i2c/aspeed_i2c.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/hw/i2c/aspeed_i2c.c b/hw/i2c/aspeed_i2c.c index d81f865..7ae99bc 100644 --- a/hw/i2c/aspeed_i2c.c +++ b/hw/i2c/aspeed_i2c.c @@ -257,7 +257,8 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value) aspeed_i2c_set_state(bus, I2CD_MACTIVE); } - if (bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST)) { + if ((bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST)) && + !(bus->intr_status & I2CD_INTR_RX_DONE)) { aspeed_i2c_handle_rx_cmd(bus); } @@ -279,6 +280,7 @@ static void aspeed_i2c_bus_write(void *opaque, hwaddr offset, uint64_t value, unsigned size) { AspeedI2CBus *bus = opaque; + bool handle_rx; switch (offset) { case I2CD_FUN_CTRL_REG: @@ -299,11 +301,17 @@ static void aspeed_i2c_bus_write(void *opaque, hwaddr offset, bus->intr_ctrl = value & 0x7FFF; break; case I2CD_INTR_STS_REG: + handle_rx = (bus->intr_status & I2CD_INTR_RX_DONE) && + (value & I2CD_INTR_RX_DONE); bus->intr_status &= ~(value & 0x7FFF); if (!bus->intr_status) { bus->controller->intr_status &= ~(1 << bus->id); qemu_irq_lower(bus->controller->irq); } + if (handle_rx && (bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST))) { + aspeed_i2c_handle_rx_cmd(bus); + aspeed_i2c_bus_raise_interrupt(bus); + } break; case I2CD_DEV_ADDR_REG: qemu_log_mask(LOG_UNIMP, "%s: slave mode not implemented\n", -- 2.7.4