diff options
Diffstat (limited to 'drivers/gpu/drm/display/drm_dp_helper.c')
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_helper.c | 127 |
1 files changed, 125 insertions, 2 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c index 6ee51003de3c..61c7c2c588c6 100644 --- a/drivers/gpu/drm/display/drm_dp_helper.c +++ b/drivers/gpu/drm/display/drm_dp_helper.c @@ -22,15 +22,16 @@ #include <linux/backlight.h> #include <linux/delay.h> +#include <linux/dynamic_debug.h> #include <linux/errno.h> #include <linux/i2c.h> #include <linux/init.h> +#include <linux/iopoll.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/sched.h> #include <linux/seq_file.h> #include <linux/string_helpers.h> -#include <linux/dynamic_debug.h> #include <drm/display/drm_dp_helper.h> #include <drm/display/drm_dp_mst_helper.h> @@ -779,6 +780,128 @@ int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux, } EXPORT_SYMBOL(drm_dp_dpcd_read_phy_link_status); +static int read_payload_update_status(struct drm_dp_aux *aux) +{ + int ret; + u8 status; + + ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status); + if (ret < 0) + return ret; + + return status; +} + +/** + * drm_dp_dpcd_write_payload() - Write Virtual Channel information to payload table + * @aux: DisplayPort AUX channel + * @vcpid: Virtual Channel Payload ID + * @start_time_slot: Starting time slot + * @time_slot_count: Time slot count + * + * Write the Virtual Channel payload allocation table, checking the payload + * update status and retrying as necessary. + * + * Returns: + * 0 on success, negative error otherwise + */ +int drm_dp_dpcd_write_payload(struct drm_dp_aux *aux, + int vcpid, u8 start_time_slot, u8 time_slot_count) +{ + u8 payload_alloc[3], status; + int ret; + int retries = 0; + + drm_dp_dpcd_writeb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, + DP_PAYLOAD_TABLE_UPDATED); + + payload_alloc[0] = vcpid; + payload_alloc[1] = start_time_slot; + payload_alloc[2] = time_slot_count; + + ret = drm_dp_dpcd_write(aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3); + if (ret != 3) { + drm_dbg_kms(aux->drm_dev, "failed to write payload allocation %d\n", ret); + goto fail; + } + +retry: + ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status); + if (ret < 0) { + drm_dbg_kms(aux->drm_dev, "failed to read payload table status %d\n", ret); + goto fail; + } + + if (!(status & DP_PAYLOAD_TABLE_UPDATED)) { + retries++; + if (retries < 20) { + usleep_range(10000, 20000); + goto retry; + } + drm_dbg_kms(aux->drm_dev, "status not set after read payload table status %d\n", + status); + ret = -EINVAL; + goto fail; + } + ret = 0; +fail: + return ret; +} +EXPORT_SYMBOL(drm_dp_dpcd_write_payload); + +/** + * drm_dp_dpcd_clear_payload() - Clear the entire VC Payload ID table + * @aux: DisplayPort AUX channel + * + * Clear the entire VC Payload ID table. + * + * Returns: 0 on success, negative error code on errors. + */ +int drm_dp_dpcd_clear_payload(struct drm_dp_aux *aux) +{ + return drm_dp_dpcd_write_payload(aux, 0, 0, 0x3f); +} +EXPORT_SYMBOL(drm_dp_dpcd_clear_payload); + +/** + * drm_dp_dpcd_poll_act_handled() - Poll for ACT handled status + * @aux: DisplayPort AUX channel + * @timeout_ms: Timeout in ms + * + * Try waiting for the sink to finish updating its payload table by polling for + * the ACT handled bit of DP_PAYLOAD_TABLE_UPDATE_STATUS for up to @timeout_ms + * milliseconds, defaulting to 3000 ms if 0. + * + * Returns: + * 0 if the ACT was handled in time, negative error code on failure. + */ +int drm_dp_dpcd_poll_act_handled(struct drm_dp_aux *aux, int timeout_ms) +{ + int ret, status; + + /* default to 3 seconds, this is arbitrary */ + timeout_ms = timeout_ms ?: 3000; + + ret = readx_poll_timeout(read_payload_update_status, aux, status, + status & DP_PAYLOAD_ACT_HANDLED || status < 0, + 200, timeout_ms * USEC_PER_MSEC); + if (ret < 0 && status >= 0) { + drm_err(aux->drm_dev, "Failed to get ACT after %d ms, last status: %02x\n", + timeout_ms, status); + return -EINVAL; + } else if (status < 0) { + /* + * Failure here isn't unexpected - the hub may have + * just been unplugged + */ + drm_dbg_kms(aux->drm_dev, "Failed to read payload table status: %d\n", status); + return status; + } + + return 0; +} +EXPORT_SYMBOL(drm_dp_dpcd_poll_act_handled); + static bool is_edid_digital_input_dp(const struct drm_edid *drm_edid) { /* FIXME: get rid of drm_edid_raw() */ @@ -2421,7 +2544,7 @@ u8 drm_dp_dsc_sink_bpp_incr(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE]) { u8 bpp_increment_dpcd = dsc_dpcd[DP_DSC_BITS_PER_PIXEL_INC - DP_DSC_SUPPORT]; - switch (bpp_increment_dpcd) { + switch (bpp_increment_dpcd & DP_DSC_BITS_PER_PIXEL_MASK) { case DP_DSC_BITS_PER_PIXEL_1_16: return 16; case DP_DSC_BITS_PER_PIXEL_1_8: |