Messages in this thread | | | Date | Mon, 24 May 2021 09:33:49 -0700 | From | khsieh@codeauro ... | Subject | Re: [PATCH 3/3] drm/msm/dp: Handle aux timeouts, nacks, defers |
| |
On 2021-05-07 14:25, Stephen Boyd wrote: > Let's look at the irq status bits after a transfer and see if we got a > nack or a defer or a timeout, instead of telling drm layers that > everything was fine, while still printing an error message. I wasn't > sure about NACK+DEFER so I lumped all those various errors along with a > nack so that the drm core can figure out that things are just not going > well. The important thing is that we're now returning -ETIMEDOUT when > the message times out and nacks for bad addresses. > > Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > Cc: Abhinav Kumar <abhinavk@codeaurora.org> > Cc: Kuogee Hsieh <khsieh@codeaurora.org> > Cc: aravindh@codeaurora.org > Cc: Sean Paul <sean@poorly.run> > Signed-off-by: Stephen Boyd <swboyd@chromium.org> > --- > drivers/gpu/drm/msm/dp/dp_aux.c | 140 ++++++++++++++------------------ > drivers/gpu/drm/msm/dp/dp_aux.h | 8 -- > 2 files changed, 61 insertions(+), 87 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c > b/drivers/gpu/drm/msm/dp/dp_aux.c > index b49810396513..4a3293b590b0 100644 > --- a/drivers/gpu/drm/msm/dp/dp_aux.c > +++ b/drivers/gpu/drm/msm/dp/dp_aux.c > @@ -9,7 +9,15 @@ > #include "dp_reg.h" > #include "dp_aux.h" > > -#define DP_AUX_ENUM_STR(x) #x > +enum msm_dp_aux_err { > + DP_AUX_ERR_NONE, > + DP_AUX_ERR_ADDR, > + DP_AUX_ERR_TOUT, > + DP_AUX_ERR_NACK, > + DP_AUX_ERR_DEFER, > + DP_AUX_ERR_NACK_DEFER, > + DP_AUX_ERR_PHY, > +}; > > struct dp_aux_private { > struct device *dev; > @@ -18,7 +26,7 @@ struct dp_aux_private { > struct mutex mutex; > struct completion comp; > > - u32 aux_error_num; > + enum msm_dp_aux_err aux_error_num; > u32 retry_cnt; > bool cmd_busy; > bool native; > @@ -33,62 +41,45 @@ struct dp_aux_private { > > #define MAX_AUX_RETRIES 5 > > -static const char *dp_aux_get_error(u32 aux_error) > -{ > - switch (aux_error) { > - case DP_AUX_ERR_NONE: > - return DP_AUX_ENUM_STR(DP_AUX_ERR_NONE); > - case DP_AUX_ERR_ADDR: > - return DP_AUX_ENUM_STR(DP_AUX_ERR_ADDR); > - case DP_AUX_ERR_TOUT: > - return DP_AUX_ENUM_STR(DP_AUX_ERR_TOUT); > - case DP_AUX_ERR_NACK: > - return DP_AUX_ENUM_STR(DP_AUX_ERR_NACK); > - case DP_AUX_ERR_DEFER: > - return DP_AUX_ENUM_STR(DP_AUX_ERR_DEFER); > - case DP_AUX_ERR_NACK_DEFER: > - return DP_AUX_ENUM_STR(DP_AUX_ERR_NACK_DEFER); > - default: > - return "unknown"; > - } > -} > - > -static u32 dp_aux_write(struct dp_aux_private *aux, > +static ssize_t dp_aux_write(struct dp_aux_private *aux, > struct drm_dp_aux_msg *msg) > { > - u32 data[4], reg, len; > + u8 data[4]; > + u32 reg; > + ssize_t len; > u8 *msgdata = msg->buffer; > int const AUX_CMD_FIFO_LEN = 128; > int i = 0; > > if (aux->read) > - len = 4; > + len = 0; > else > - len = msg->size + 4; > + len = msg->size; > > /* > * cmd fifo only has depth of 144 bytes > * limit buf length to 128 bytes here > */ > - if (len > AUX_CMD_FIFO_LEN) { > + if (len > AUX_CMD_FIFO_LEN - 4) { > DRM_ERROR("buf size greater than allowed size of 128 bytes\n"); > - return 0; > + return -EINVAL; > } > > /* Pack cmd and write to HW */ > - data[0] = (msg->address >> 16) & 0xf; /* addr[19:16] */ > + data[0] = (msg->address >> 16) & 0xf; /* addr[19:16] */ > if (aux->read) > - data[0] |= BIT(4); /* R/W */ > + data[0] |= BIT(4); /* R/W */ > > - data[1] = (msg->address >> 8) & 0xff; /* addr[15:8] */ > - data[2] = msg->address & 0xff; /* addr[7:0] */ > - data[3] = (msg->size - 1) & 0xff; /* len[7:0] */ > + data[1] = msg->address >> 8; /* addr[15:8] */ > + data[2] = msg->address; /* addr[7:0] */ > + data[3] = msg->size - 1; /* len[7:0] */ > > - for (i = 0; i < len; i++) { > + for (i = 0; i < len + 4; i++) { > reg = (i < 4) ? data[i] : msgdata[i - 4]; > + reg <<= DP_AUX_DATA_OFFSET; > + reg &= DP_AUX_DATA_MASK; > + reg |= DP_AUX_DATA_WRITE; > /* index = 0, write */ > - reg = (((reg) << DP_AUX_DATA_OFFSET) > - & DP_AUX_DATA_MASK) | DP_AUX_DATA_WRITE; > if (i == 0) > reg |= DP_AUX_DATA_INDEX_WRITE; > aux->catalog->aux_data = reg; > @@ -116,39 +107,27 @@ static u32 dp_aux_write(struct dp_aux_private > *aux, > return len; > } > > -static int dp_aux_cmd_fifo_tx(struct dp_aux_private *aux, > +static ssize_t dp_aux_cmd_fifo_tx(struct dp_aux_private *aux, > struct drm_dp_aux_msg *msg) > { > - u32 ret, len, timeout; > - int aux_timeout_ms = HZ/4; > + ssize_t ret; > + unsigned long time_left; > > reinit_completion(&aux->comp); > > - len = dp_aux_write(aux, msg); > - if (len == 0) { > - DRM_ERROR("DP AUX write failed\n"); > - return -EINVAL; > - } > + ret = dp_aux_write(aux, msg); > + if (ret < 0) > + return ret; > > - timeout = wait_for_completion_timeout(&aux->comp, aux_timeout_ms); > - if (!timeout) { > - DRM_ERROR("aux %s timeout\n", (aux->read ? "read" : "write")); > + time_left = wait_for_completion_timeout(&aux->comp, > + msecs_to_jiffies(250)); > + if (!time_left) > return -ETIMEDOUT; > - } > - > - if (aux->aux_error_num == DP_AUX_ERR_NONE) { > - ret = len; > - } else { > - DRM_ERROR_RATELIMITED("aux err: %s\n", > - dp_aux_get_error(aux->aux_error_num)); > - > - ret = -EINVAL; > - } > > return ret; > } > > -static void dp_aux_cmd_fifo_rx(struct dp_aux_private *aux, > +static ssize_t dp_aux_cmd_fifo_rx(struct dp_aux_private *aux, > struct drm_dp_aux_msg *msg) > { > u32 data; > @@ -175,9 +154,10 @@ static void dp_aux_cmd_fifo_rx(struct > dp_aux_private *aux, > > actual_i = (data >> DP_AUX_DATA_INDEX_OFFSET) & 0xFF; > if (i != actual_i) > - DRM_ERROR("Index mismatch: expected %d, found %d\n", > - i, actual_i); > + break; > } > + > + return i; > } > > static void dp_aux_native_handler(struct dp_aux_private *aux, u32 isr) > @@ -367,36 +347,38 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux > *dp_aux, > } > > ret = dp_aux_cmd_fifo_tx(aux, msg); > - > if (ret < 0) { > if (aux->native) { > aux->retry_cnt++; > if (!(aux->retry_cnt % MAX_AUX_RETRIES)) > dp_catalog_aux_update_cfg(aux->catalog); > } > - usleep_range(400, 500); /* at least 400us to next try */ > - goto unlock_exit; > - }
1) dp_catalog_aux_update_cfg(aux->catalog) will not work without dp_catalog_aux_reset(aux->catalog); dp_catalog_aux_reset(aux->catalog) will reset hpd control block and potentially cause pending hpd interrupts got lost. Therefore I think we should not do dp_catalog_aux_update_cfg(aux->catalog) for now. reset aux controller will reset hpd control block probolem will be fixed at next chipset. after that we can add dp_catalog_aux_update_cfg(aux->catalog) followed by dp_catalog_aux_reset(aux->catalog) back at next chipset.
2) according to DP specification, aux read/write failed have to wait at least 400us before next try can start. Otherwise, DP compliant test will failed
> - > - if (aux->aux_error_num == DP_AUX_ERR_NONE) { > - if (aux->read) > - dp_aux_cmd_fifo_rx(aux, msg); > - > - msg->reply = aux->native ? > - DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK; > } else { > - /* Reply defer to retry */ > - msg->reply = aux->native ? > - DP_AUX_NATIVE_REPLY_DEFER : DP_AUX_I2C_REPLY_DEFER; > + aux->retry_cnt = 0; > + switch (aux->aux_error_num) { > + case DP_AUX_ERR_NONE: > + if (aux->read) > + ret = dp_aux_cmd_fifo_rx(aux, msg); > + msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_ACK : > DP_AUX_I2C_REPLY_ACK; > + break; > + case DP_AUX_ERR_DEFER: > + msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_DEFER : > DP_AUX_I2C_REPLY_DEFER; > + break; > + case DP_AUX_ERR_PHY: > + case DP_AUX_ERR_ADDR: > + case DP_AUX_ERR_NACK: > + case DP_AUX_ERR_NACK_DEFER: > + msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_NACK : > DP_AUX_I2C_REPLY_NACK; > + break; > + case DP_AUX_ERR_TOUT: > + ret = -ETIMEDOUT; > + break; > + } > } > > - /* Return requested size for success or retry */ > - ret = msg->size; > - aux->retry_cnt = 0; > - > -unlock_exit: > aux->cmd_busy = false; > mutex_unlock(&aux->mutex); > + > return ret; > } > > diff --git a/drivers/gpu/drm/msm/dp/dp_aux.h > b/drivers/gpu/drm/msm/dp/dp_aux.h > index f8b8ba919465..0728cc09c9ec 100644 > --- a/drivers/gpu/drm/msm/dp/dp_aux.h > +++ b/drivers/gpu/drm/msm/dp/dp_aux.h > @@ -9,14 +9,6 @@ > #include "dp_catalog.h" > #include <drm/drm_dp_helper.h> > > -#define DP_AUX_ERR_NONE 0 > -#define DP_AUX_ERR_ADDR -1 > -#define DP_AUX_ERR_TOUT -2 > -#define DP_AUX_ERR_NACK -3 > -#define DP_AUX_ERR_DEFER -4 > -#define DP_AUX_ERR_NACK_DEFER -5 > -#define DP_AUX_ERR_PHY -6 > - > int dp_aux_register(struct drm_dp_aux *dp_aux); > void dp_aux_unregister(struct drm_dp_aux *dp_aux); > void dp_aux_isr(struct drm_dp_aux *dp_aux);
| |