From 1d407096002becab2fd5b19253cee0de65aab668 Mon Sep 17 00:00:00 2001 From: Michal Wajdeczko Date: Mon, 26 Mar 2018 19:48:23 +0000 Subject: drm/i915/guc: Prepare to handle messages from CT RECV buffer GuC can respond to our commands not only by updating SEND buffer descriptor, but can also send a response message over RECV buffer. Guc can also send unsolicited request messages over RECV buffer. Let's start reading those messages and make placeholders for actual response/request handlers. v2: misc improvements (Michal) v3: change response detection (Michal) invalid status is protocol error (Michal) v4: rebase v5: fix checkpatch (Michel) don't use fields before check (Jani) add some documentation (Michal) Signed-off-by: Michal Wajdeczko Cc: Oscar Mateo Cc: Michel Thierry Cc: Daniele Ceraolo Spurio Reviewed-by: Michel Thierry # 4.5 Cc: Jani Nikula Signed-off-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20180326194829.58836-7-michal.wajdeczko@intel.com --- drivers/gpu/drm/i915/intel_guc_ct.c | 184 +++++++++++++++++++++++++++++++++++- 1 file changed, 183 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/i915/intel_guc_ct.c') diff --git a/drivers/gpu/drm/i915/intel_guc_ct.c b/drivers/gpu/drm/i915/intel_guc_ct.c index a54bf58c64ab..14f55de342e7 100644 --- a/drivers/gpu/drm/i915/intel_guc_ct.c +++ b/drivers/gpu/drm/i915/intel_guc_ct.c @@ -273,6 +273,24 @@ static u32 ctch_get_next_fence(struct intel_guc_ct_channel *ctch) return ++ctch->next_fence; } +/** + * DOC: CTB Host to GuC request + * + * Format of the CTB Host to GuC request message is as follows:: + * + * +------------+---------+---------+---------+---------+ + * | msg[0] | [1] | [2] | ... | [n-1] | + * +------------+---------+---------+---------+---------+ + * | MESSAGE | MESSAGE PAYLOAD | + * + HEADER +---------+---------+---------+---------+ + * | | 0 | 1 | ... | n | + * +============+=========+=========+=========+=========+ + * | len >= 1 | FENCE | request specific data | + * +------+-----+---------+---------+---------+---------+ + * + * ^-----------------len-------------------^ + */ + static int ctb_write(struct intel_guc_ct_buffer *ctb, const u32 *action, u32 len /* in dwords */, @@ -305,7 +323,8 @@ static int ctb_write(struct intel_guc_ct_buffer *ctb, if (unlikely(used + len + 1 >= size)) return -ENOSPC; - /* Write the message. The format is the following: + /* + * Write the message. The format is the following: * DW0: header (including action code) * DW1: fence * DW2+: action data @@ -427,6 +446,167 @@ static int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len, return ret; } +static inline unsigned int ct_header_get_len(u32 header) +{ + return (header >> GUC_CT_MSG_LEN_SHIFT) & GUC_CT_MSG_LEN_MASK; +} + +static inline unsigned int ct_header_get_action(u32 header) +{ + return (header >> GUC_CT_MSG_ACTION_SHIFT) & GUC_CT_MSG_ACTION_MASK; +} + +static inline bool ct_header_is_response(u32 header) +{ + return ct_header_get_action(header) == INTEL_GUC_ACTION_DEFAULT; +} + +static int ctb_read(struct intel_guc_ct_buffer *ctb, u32 *data) +{ + struct guc_ct_buffer_desc *desc = ctb->desc; + u32 head = desc->head / 4; /* in dwords */ + u32 tail = desc->tail / 4; /* in dwords */ + u32 size = desc->size / 4; /* in dwords */ + u32 *cmds = ctb->cmds; + s32 available; /* in dwords */ + unsigned int len; + unsigned int i; + + GEM_BUG_ON(desc->size % 4); + GEM_BUG_ON(desc->head % 4); + GEM_BUG_ON(desc->tail % 4); + GEM_BUG_ON(tail >= size); + GEM_BUG_ON(head >= size); + + /* tail == head condition indicates empty */ + available = tail - head; + if (unlikely(available == 0)) + return -ENODATA; + + /* beware of buffer wrap case */ + if (unlikely(available < 0)) + available += size; + GEM_BUG_ON(available < 0); + + data[0] = cmds[head]; + head = (head + 1) % size; + + /* message len with header */ + len = ct_header_get_len(data[0]) + 1; + if (unlikely(len > (u32)available)) { + DRM_ERROR("CT: incomplete message %*phn %*phn %*phn\n", + 4, data, + 4 * (head + available - 1 > size ? + size - head : available - 1), &cmds[head], + 4 * (head + available - 1 > size ? + available - 1 - size + head : 0), &cmds[0]); + return -EPROTO; + } + + for (i = 1; i < len; i++) { + data[i] = cmds[head]; + head = (head + 1) % size; + } + + desc->head = head * 4; + return 0; +} + +/** + * DOC: CTB GuC to Host response + * + * Format of the CTB GuC to Host response message is as follows:: + * + * +------------+---------+---------+---------+---------+---------+ + * | msg[0] | [1] | [2] | [3] | ... | [n-1] | + * +------------+---------+---------+---------+---------+---------+ + * | MESSAGE | MESSAGE PAYLOAD | + * + HEADER +---------+---------+---------+---------+---------+ + * | | 0 | 1 | 2 | ... | n | + * +============+=========+=========+=========+=========+=========+ + * | len >= 2 | FENCE | STATUS | response specific data | + * +------+-----+---------+---------+---------+---------+---------+ + * + * ^-----------------------len-----------------------^ + */ + +static int ct_handle_response(struct intel_guc_ct *ct, const u32 *msg) +{ + u32 header = msg[0]; + u32 len = ct_header_get_len(header); + u32 msglen = len + 1; /* total message length including header */ + u32 fence; + u32 status; + + GEM_BUG_ON(!ct_header_is_response(header)); + + /* Response payload shall at least include fence and status */ + if (unlikely(len < 2)) { + DRM_ERROR("CT: corrupted response %*phn\n", 4 * msglen, msg); + return -EPROTO; + } + + fence = msg[1]; + status = msg[2]; + + /* Format of the status follows RESPONSE message */ + if (unlikely(!INTEL_GUC_MSG_IS_RESPONSE(status))) { + DRM_ERROR("CT: corrupted response %*phn\n", 4 * msglen, msg); + return -EPROTO; + } + + /* XXX */ + return 0; +} + +static int ct_handle_request(struct intel_guc_ct *ct, const u32 *msg) +{ + u32 header = msg[0]; + + GEM_BUG_ON(ct_header_is_response(header)); + + /* XXX */ + return 0; +} + +static void ct_process_host_channel(struct intel_guc_ct *ct) +{ + struct intel_guc_ct_channel *ctch = &ct->host_channel; + struct intel_guc_ct_buffer *ctb = &ctch->ctbs[CTB_RECV]; + u32 msg[GUC_CT_MSG_LEN_MASK + 1]; /* one extra dw for the header */ + int err = 0; + + if (!ctch_is_open(ctch)) + return; + + do { + err = ctb_read(ctb, msg); + if (err) + break; + + if (ct_header_is_response(msg[0])) + err = ct_handle_response(ct, msg); + else + err = ct_handle_request(ct, msg); + } while (!err); + + if (GEM_WARN_ON(err == -EPROTO)) { + DRM_ERROR("CT: corrupted message detected!\n"); + ctb->desc->is_in_error = 1; + } +} + +/* + * When we're communicating with the GuC over CT, GuC uses events + * to notify us about new messages being posted on the RECV buffer. + */ +static void intel_guc_to_host_event_handler_ct(struct intel_guc *guc) +{ + struct intel_guc_ct *ct = &guc->ct; + + ct_process_host_channel(ct); +} + /** * intel_guc_ct_enable - Enable buffer based command transport. * @ct: pointer to CT struct @@ -450,6 +630,7 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct) /* Switch into cmd transport buffer based send() */ guc->send = intel_guc_send_ct; + guc->handler = intel_guc_to_host_event_handler_ct; DRM_INFO("CT: %s\n", enableddisabled(true)); return 0; } @@ -475,5 +656,6 @@ void intel_guc_ct_disable(struct intel_guc_ct *ct) /* Disable send */ guc->send = intel_guc_send_nop; + guc->handler = intel_guc_to_host_event_handler_nop; DRM_INFO("CT: %s\n", enableddisabled(false)); } -- cgit v1.2.3