diff options
Diffstat (limited to 'drivers/gpu/drm/display/drm_dp_helper.c')
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_helper.c | 179 |
1 files changed, 169 insertions, 10 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c index b1ca3a1100da..266826eac4a7 100644 --- a/drivers/gpu/drm/display/drm_dp_helper.c +++ b/drivers/gpu/drm/display/drm_dp_helper.c @@ -533,6 +533,15 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, mutex_lock(&aux->hw_mutex); /* + * If the device attached to the aux bus is powered down then there's + * no reason to attempt a transfer. Error out immediately. + */ + if (aux->powered_down) { + ret = -EBUSY; + goto unlock; + } + + /* * The specification doesn't give any recommendation on how often to * retry native transactions. We used to retry 7 times like for * aux i2c transactions but real world devices this wasn't @@ -600,6 +609,29 @@ int drm_dp_dpcd_probe(struct drm_dp_aux *aux, unsigned int offset) EXPORT_SYMBOL(drm_dp_dpcd_probe); /** + * drm_dp_dpcd_set_powered() - Set whether the DP device is powered + * @aux: DisplayPort AUX channel; for convenience it's OK to pass NULL here + * and the function will be a no-op. + * @powered: true if powered; false if not + * + * If the endpoint device on the DP AUX bus is known to be powered down + * then this function can be called to make future transfers fail immediately + * instead of needing to time out. + * + * If this function is never called then a device defaults to being powered. + */ +void drm_dp_dpcd_set_powered(struct drm_dp_aux *aux, bool powered) +{ + if (!aux) + return; + + mutex_lock(&aux->hw_mutex); + aux->powered_down = !powered; + mutex_unlock(&aux->hw_mutex); +} +EXPORT_SYMBOL(drm_dp_dpcd_set_powered); + +/** * drm_dp_dpcd_read() - read a series of bytes from the DPCD * @aux: DisplayPort AUX channel (SST or MST) * @offset: address of the (first) register to read @@ -1858,6 +1890,9 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, struct drm_dp_aux_msg msg; int err = 0; + if (aux->powered_down) + return -EBUSY; + dp_aux_i2c_transfer_size = clamp(dp_aux_i2c_transfer_size, 1, DP_AUX_MAX_PAYLOAD_BYTES); memset(&msg, 0, sizeof(msg)); @@ -2897,26 +2932,120 @@ static const char *dp_content_type_get_name(enum dp_content_type content_type) } } -void drm_dp_vsc_sdp_log(const char *level, struct device *dev, - const struct drm_dp_vsc_sdp *vsc) +void drm_dp_vsc_sdp_log(struct drm_printer *p, const struct drm_dp_vsc_sdp *vsc) { -#define DP_SDP_LOG(fmt, ...) dev_printk(level, dev, fmt, ##__VA_ARGS__) - DP_SDP_LOG("DP SDP: %s, revision %u, length %u\n", "VSC", + drm_printf(p, "DP SDP: VSC, revision %u, length %u\n", vsc->revision, vsc->length); - DP_SDP_LOG(" pixelformat: %s\n", + drm_printf(p, " pixelformat: %s\n", dp_pixelformat_get_name(vsc->pixelformat)); - DP_SDP_LOG(" colorimetry: %s\n", + drm_printf(p, " colorimetry: %s\n", dp_colorimetry_get_name(vsc->pixelformat, vsc->colorimetry)); - DP_SDP_LOG(" bpc: %u\n", vsc->bpc); - DP_SDP_LOG(" dynamic range: %s\n", + drm_printf(p, " bpc: %u\n", vsc->bpc); + drm_printf(p, " dynamic range: %s\n", dp_dynamic_range_get_name(vsc->dynamic_range)); - DP_SDP_LOG(" content type: %s\n", + drm_printf(p, " content type: %s\n", dp_content_type_get_name(vsc->content_type)); -#undef DP_SDP_LOG } EXPORT_SYMBOL(drm_dp_vsc_sdp_log); /** + * drm_dp_vsc_sdp_supported() - check if vsc sdp is supported + * @aux: DisplayPort AUX channel + * @dpcd: DisplayPort configuration data + * + * Returns true if vsc sdp is supported, else returns false + */ +bool drm_dp_vsc_sdp_supported(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]) +{ + u8 rx_feature; + + if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_13) + return false; + + if (drm_dp_dpcd_readb(aux, DP_DPRX_FEATURE_ENUMERATION_LIST, &rx_feature) != 1) { + drm_dbg_dp(aux->drm_dev, "failed to read DP_DPRX_FEATURE_ENUMERATION_LIST\n"); + return false; + } + + return (rx_feature & DP_VSC_SDP_EXT_FOR_COLORIMETRY_SUPPORTED); +} +EXPORT_SYMBOL(drm_dp_vsc_sdp_supported); + +/** + * drm_dp_vsc_sdp_pack() - pack a given vsc sdp into generic dp_sdp + * @vsc: vsc sdp initialized according to its purpose as defined in + * table 2-118 - table 2-120 in DP 1.4a specification + * @sdp: valid handle to the generic dp_sdp which will be packed + * + * Returns length of sdp on success and error code on failure + */ +ssize_t drm_dp_vsc_sdp_pack(const struct drm_dp_vsc_sdp *vsc, + struct dp_sdp *sdp) +{ + size_t length = sizeof(struct dp_sdp); + + memset(sdp, 0, sizeof(struct dp_sdp)); + + /* + * Prepare VSC Header for SU as per DP 1.4a spec, Table 2-119 + * VSC SDP Header Bytes + */ + sdp->sdp_header.HB0 = 0; /* Secondary-Data Packet ID = 0 */ + sdp->sdp_header.HB1 = vsc->sdp_type; /* Secondary-data Packet Type */ + sdp->sdp_header.HB2 = vsc->revision; /* Revision Number */ + sdp->sdp_header.HB3 = vsc->length; /* Number of Valid Data Bytes */ + + if (vsc->revision == 0x6) { + sdp->db[0] = 1; + sdp->db[3] = 1; + } + + /* + * Revision 0x5 and revision 0x7 supports Pixel Encoding/Colorimetry + * Format as per DP 1.4a spec and DP 2.0 respectively. + */ + if (!(vsc->revision == 0x5 || vsc->revision == 0x7)) + goto out; + + /* VSC SDP Payload for DB16 through DB18 */ + /* Pixel Encoding and Colorimetry Formats */ + sdp->db[16] = (vsc->pixelformat & 0xf) << 4; /* DB16[7:4] */ + sdp->db[16] |= vsc->colorimetry & 0xf; /* DB16[3:0] */ + + switch (vsc->bpc) { + case 6: + /* 6bpc: 0x0 */ + break; + case 8: + sdp->db[17] = 0x1; /* DB17[3:0] */ + break; + case 10: + sdp->db[17] = 0x2; + break; + case 12: + sdp->db[17] = 0x3; + break; + case 16: + sdp->db[17] = 0x4; + break; + default: + WARN(1, "Missing case %d\n", vsc->bpc); + return -EINVAL; + } + + /* Dynamic Range and Component Bit Depth */ + if (vsc->dynamic_range == DP_DYNAMIC_RANGE_CTA) + sdp->db[17] |= 0x80; /* DB17[7] */ + + /* Content Type */ + sdp->db[18] = vsc->content_type & 0x7; + +out: + return length; +} +EXPORT_SYMBOL(drm_dp_vsc_sdp_pack); + +/** * drm_dp_get_pcon_max_frl_bw() - maximum frl supported by PCON * @dpcd: DisplayPort configuration data * @port_cap: port capabilities @@ -4058,3 +4187,33 @@ int drm_dp_bw_channel_coding_efficiency(bool is_uhbr) return 800000; } EXPORT_SYMBOL(drm_dp_bw_channel_coding_efficiency); + +/** + * drm_dp_max_dprx_data_rate - Get the max data bandwidth of a DPRX sink + * @max_link_rate: max DPRX link rate in 10kbps units + * @max_lanes: max DPRX lane count + * + * Given a link rate and lanes, get the data bandwidth. + * + * Data bandwidth is the actual payload rate, which depends on the data + * bandwidth efficiency and the link rate. + * + * Note that protocol layers above the DPRX link level considered here can + * further limit the maximum data rate. Such layers are the MST topology (with + * limits on the link between the source and first branch device as well as on + * the whole MST path until the DPRX link) and (Thunderbolt) DP tunnels - + * which in turn can encapsulate an MST link with its own limit - with each + * SST or MST encapsulated tunnel sharing the BW of a tunnel group. + * + * Returns the maximum data rate in kBps units. + */ +int drm_dp_max_dprx_data_rate(int max_link_rate, int max_lanes) +{ + int ch_coding_efficiency = + drm_dp_bw_channel_coding_efficiency(drm_dp_is_uhbr_rate(max_link_rate)); + + return DIV_ROUND_DOWN_ULL(mul_u32_u32(max_link_rate * 10 * max_lanes, + ch_coding_efficiency), + 1000000 * 8); +} +EXPORT_SYMBOL(drm_dp_max_dprx_data_rate); |