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Message-ID: <20180912233035.GA10713@roeck-us.net>
Date: Wed, 12 Sep 2018 16:30:35 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Jae Hyun Yoo <jae.hyun.yoo@...ux.intel.com>
Cc: Joel Stanley <joel@....id.au>, linux-aspeed@...ts.ozlabs.org,
Vernon Mauery <vernon.mauery@...ux.intel.com>,
OpenBMC Maillist <openbmc@...ts.ozlabs.org>,
Brendan Higgins <brendanhiggins@...gle.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-i2c@...r.kernel.org, jarkko.nikula@...ux.intel.com,
Cédric Le Goater <clg@...d.org>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
James Feist <james.feist@...ux.intel.com>
Subject: Re: [PATCH i2c-next v6] i2c: aspeed: Handle master/slave combined
irq events properly
On Wed, Sep 12, 2018 at 03:31:06PM -0700, Jae Hyun Yoo wrote:
> >
> >I played with the code on both sides. I had to make changes in both
> >the linux kernel and in qemu to get the code to work again.
> >See attached.
> >
> >Guenter
> >
> >---
> >Linux:
> >
> >diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
> >index c258c4d9a4c0..3d518e09369f 100644
> >--- a/drivers/i2c/busses/i2c-aspeed.c
> >+++ b/drivers/i2c/busses/i2c-aspeed.c
> >@@ -552,6 +552,9 @@ static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
> > spin_lock(&bus->lock);
> > irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
> >+ /* Ack all interrupts except for Rx done */
> >+ writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,
> >+ bus->base + ASPEED_I2C_INTR_STS_REG);
> > irq_remaining = irq_received;
> > #if IS_ENABLED(CONFIG_I2C_SLAVE)
> >@@ -584,8 +587,10 @@ static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
> > "irq handled != irq. expected 0x%08x, but was 0x%08x\n",
> > irq_received, irq_handled);
> >- /* Ack all interrupt bits. */
> >- writel(irq_received, bus->base + ASPEED_I2C_INTR_STS_REG);
> >+ /* Ack Rx done */
> >+ if (irq_received & ASPEED_I2CD_INTR_RX_DONE)
> >+ writel(ASPEED_I2CD_INTR_RX_DONE,
> >+ bus->base + ASPEED_I2C_INTR_STS_REG);
> > spin_unlock(&bus->lock);
> > return irq_remaining ? IRQ_NONE : IRQ_HANDLED;
> > }
> >
> >---
> >qemu:
> >
> >diff --git a/hw/i2c/aspeed_i2c.c b/hw/i2c/aspeed_i2c.c
> >index c762c73..0d4aa08 100644
> >--- a/hw/i2c/aspeed_i2c.c
> >+++ b/hw/i2c/aspeed_i2c.c
> >@@ -180,6 +180,33 @@ static uint8_t aspeed_i2c_get_state(AspeedI2CBus *bus)
> > return (bus->cmd >> I2CD_TX_STATE_SHIFT) & I2CD_TX_STATE_MASK;
> > }
> >+static void aspeed_i2c_handle_rx_cmd(AspeedI2CBus *bus)
> >+{
> >+ int ret;
> >+
> >+ if (!(bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST))) {
> >+ return;
> >+ }
> >+ if (bus->intr_status & I2CD_INTR_RX_DONE) {
> >+ return;
> >+ }
> >+
> >+ aspeed_i2c_set_state(bus, I2CD_MRXD);
> >+ ret = i2c_recv(bus->bus);
> >+ if (ret < 0) {
> >+ qemu_log_mask(LOG_GUEST_ERROR, "%s: read failed\n", __func__);
> >+ ret = 0xff;
> >+ } else {
> >+ bus->intr_status |= I2CD_INTR_RX_DONE;
> >+ }
> >+ bus->buf = (ret & I2CD_BYTE_BUF_RX_MASK) << I2CD_BYTE_BUF_RX_SHIFT;
> >+ if (bus->cmd & I2CD_M_S_RX_CMD_LAST) {
> >+ i2c_nack(bus->bus);
> >+ }
> >+ bus->cmd &= ~(I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST);
> >+ aspeed_i2c_set_state(bus, I2CD_MACTIVE);
> >+}
> >+
> > /*
> > * The state machine needs some refinement. It is only used to track
> > * invalid STOP commands for the moment.
> >@@ -188,7 +215,7 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value)
> > {
> > bus->cmd &= ~0xFFFF;
> > bus->cmd |= value & 0xFFFF;
> >- bus->intr_status = 0;
> >+ bus->intr_status &= I2CD_INTR_RX_DONE;
> > if (bus->cmd & I2CD_M_START_CMD) {
> > uint8_t state = aspeed_i2c_get_state(bus) & I2CD_MACTIVE ?
> >@@ -227,22 +254,7 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value)
> > }
> > if (bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST)) {
> >- int ret;
> >-
> >- aspeed_i2c_set_state(bus, I2CD_MRXD);
> >- ret = i2c_recv(bus->bus);
> >- if (ret < 0) {
> >- qemu_log_mask(LOG_GUEST_ERROR, "%s: read failed\n", __func__);
> >- ret = 0xff;
> >- } else {
> >- bus->intr_status |= I2CD_INTR_RX_DONE;
> >- }
> >- bus->buf = (ret & I2CD_BYTE_BUF_RX_MASK) << I2CD_BYTE_BUF_RX_SHIFT;
> >- if (bus->cmd & I2CD_M_S_RX_CMD_LAST) {
> >- i2c_nack(bus->bus);
> >- }
> >- bus->cmd &= ~(I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST);
> >- aspeed_i2c_set_state(bus, I2CD_MACTIVE);
> >+ aspeed_i2c_handle_rx_cmd(bus);
> > }
> > if (bus->cmd & I2CD_M_STOP_CMD) {
> >@@ -263,6 +275,7 @@ static void aspeed_i2c_bus_write(void *opaque, hwaddr offset,
> > uint64_t value, unsigned size)
> > {
> > AspeedI2CBus *bus = opaque;
> >+ int status;
> > switch (offset) {
> > case I2CD_FUN_CTRL_REG:
> >@@ -283,9 +296,16 @@ static void aspeed_i2c_bus_write(void *opaque, hwaddr offset,
> > bus->intr_ctrl = value & 0x7FFF;
> > break;
> > case I2CD_INTR_STS_REG:
> >+ status = bus->intr_status;
> > bus->intr_status &= ~(value & 0x7FFF);
> >- bus->controller->intr_status &= ~(1 << bus->id);
> >- qemu_irq_lower(bus->controller->irq);
> >+ if (!bus->intr_status) {
> >+ bus->controller->intr_status &= ~(1 << bus->id);
> >+ qemu_irq_lower(bus->controller->irq);
> >+ }
> >+ if ((status & I2CD_INTR_RX_DONE) && !(bus->intr_status & I2CD_INTR_RX_DONE)) {
> >+ 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",
> >
>
> Nice fix! LGTM. I've tested the new patch and checked that it works well
> on both low and high bus speed environments. Thanks a lot!
>
> Can you please submit this patch?
>
Assuming you mean both patches, sure, can do. I'll need to clean up
the qemu patch a bit, though; it looks too messy for my liking.
Guenter
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