[PATCH 4/4] Revert "platform/chrome: cros_ec_spi: Transfer messages at high priority"

[Douglas Anderson]

This reverts commit 37a186225a0c020516bafad2727fdcdfc039a1e4.

We have a better solution in the patch ("platform/chrome: cros_ec_spi:
Set ourselves as timing sensitive").  Let's revert the uglier and less
reliable solution.

Signed-off-by: Douglas Anderson <diand...@chromium.org>
---

 drivers/platform/chrome/cros_ec_spi.c | 80 ++-------------------------
 1 file changed, 6 insertions(+), 74 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_spi.c 
b/drivers/platform/chrome/cros_ec_spi.c
index 757a115502ec..70ff1ad09012 100644
--- a/drivers/platform/chrome/cros_ec_spi.c
+++ b/drivers/platform/chrome/cros_ec_spi.c
@@ -75,27 +75,6 @@ struct cros_ec_spi {
        unsigned int end_of_msg_delay;
 };
 
-typedef int (*cros_ec_xfer_fn_t) (struct cros_ec_device *ec_dev,
-                                 struct cros_ec_command *ec_msg);
-
-/**
- * struct cros_ec_xfer_work_params - params for our high priority workers
- *
- * @work: The work_struct needed to queue work
- * @fn: The function to use to transfer
- * @ec_dev: ChromeOS EC device
- * @ec_msg: Message to transfer
- * @ret: The return value of the function
- */
-
-struct cros_ec_xfer_work_params {
-       struct work_struct work;
-       cros_ec_xfer_fn_t fn;
-       struct cros_ec_device *ec_dev;
-       struct cros_ec_command *ec_msg;
-       int ret;
-};
-
 static void debug_packet(struct device *dev, const char *name, u8 *ptr,
                         int len)
 {
@@ -371,13 +350,13 @@ static int cros_ec_spi_receive_response(struct 
cros_ec_device *ec_dev,
 }
 
 /**
- * do_cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply
+ * cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply
  *
  * @ec_dev: ChromeOS EC device
  * @ec_msg: Message to transfer
  */
-static int do_cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
-                                  struct cros_ec_command *ec_msg)
+static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
+                               struct cros_ec_command *ec_msg)
 {
        struct ec_host_response *response;
        struct cros_ec_spi *ec_spi = ec_dev->priv;
@@ -514,13 +493,13 @@ static int do_cros_ec_pkt_xfer_spi(struct cros_ec_device 
*ec_dev,
 }
 
 /**
- * do_cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply
+ * cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply
  *
  * @ec_dev: ChromeOS EC device
  * @ec_msg: Message to transfer
  */
-static int do_cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
-                                  struct cros_ec_command *ec_msg)
+static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
+                               struct cros_ec_command *ec_msg)
 {
        struct cros_ec_spi *ec_spi = ec_dev->priv;
        struct spi_transfer trans;
@@ -632,53 +611,6 @@ static int do_cros_ec_cmd_xfer_spi(struct cros_ec_device 
*ec_dev,
        return ret;
 }
 
-static void cros_ec_xfer_high_pri_work(struct work_struct *work)
-{
-       struct cros_ec_xfer_work_params *params;
-
-       params = container_of(work, struct cros_ec_xfer_work_params, work);
-       params->ret = params->fn(params->ec_dev, params->ec_msg);
-}
-
-static int cros_ec_xfer_high_pri(struct cros_ec_device *ec_dev,
-                                struct cros_ec_command *ec_msg,
-                                cros_ec_xfer_fn_t fn)
-{
-       struct cros_ec_xfer_work_params params;
-
-       INIT_WORK_ONSTACK(&params.work, cros_ec_xfer_high_pri_work);
-       params.ec_dev = ec_dev;
-       params.ec_msg = ec_msg;
-       params.fn = fn;
-
-       /*
-        * This looks a bit ridiculous.  Why do the work on a
-        * different thread if we're just going to block waiting for
-        * the thread to finish?  The key here is that the thread is
-        * running at high priority but the calling context might not
-        * be.  We need to be at high priority to avoid getting
-        * context switched out for too long and the EC giving up on
-        * the transfer.
-        */
-       queue_work(system_highpri_wq, &params.work);
-       flush_work(&params.work);
-       destroy_work_on_stack(&params.work);
-
-       return params.ret;
-}
-
-static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
-                               struct cros_ec_command *ec_msg)
-{
-       return cros_ec_xfer_high_pri(ec_dev, ec_msg, do_cros_ec_pkt_xfer_spi);
-}
-
-static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
-                               struct cros_ec_command *ec_msg)
-{
-       return cros_ec_xfer_high_pri(ec_dev, ec_msg, do_cros_ec_cmd_xfer_spi);
-}
-
 static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device 
*dev)
 {
        struct device_node *np = dev->of_node;
-- 
2.21.0.1020.gf2820cf01a-goog