1 files changed, 19 insertions, 29 deletions

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 4446fa6c820e..d9ce4b162e2c 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -39,6 +39,7 @@
 
 #include <linux/cpufreq.h>
 #include <linux/delay.h>
+#include <linux/iopoll.h>
 #include <linux/ktime.h>
 #include <linux/rwsem.h>
 #include <linux/wait.h>
@@ -49,7 +50,7 @@ struct cppc_pcc_data {
         struct mbox_chan *pcc_channel;
         void __iomem *pcc_comm_addr;
         bool pcc_channel_acquired;
-        ktime_t deadline;
+        unsigned int deadline_us;
         unsigned int pcc_mpar, pcc_mrtt, pcc_nominal;
 
         bool pending_pcc_write_cmd;     /* Any pending/batched PCC write cmds? */
@@ -198,42 +199,31 @@ static struct kobj_type cppc_ktype = {
 
 static int check_pcc_chan(int pcc_ss_id, bool chk_err_bit)
 {
-        int ret = -EIO, status = 0;
+        int ret, status;
         struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
         struct acpi_pcct_shared_memory __iomem *generic_comm_base =
                 pcc_ss_data->pcc_comm_addr;
-        ktime_t next_deadline = ktime_add(ktime_get(),
-                                          pcc_ss_data->deadline);
 
         if (!pcc_ss_data->platform_owns_pcc)
                 return 0;
 
-        /* Retry in case the remote processor was too slow to catch up. */
-        while (!ktime_after(ktime_get(), next_deadline)) {
-                /*
-                 * Per spec, prior to boot the PCC space wil be initialized by
-                 * platform and should have set the command completion bit when
-                 * PCC can be used by OSPM
-                 */
-                status = readw_relaxed(&generic_comm_base->status);
-                if (status & PCC_CMD_COMPLETE_MASK) {
-                        ret = 0;
-                        if (chk_err_bit && (status & PCC_ERROR_MASK))
-                                ret = -EIO;
-                        break;
-                }
-                /*
-                 * Reducing the bus traffic in case this loop takes longer than
-                 * a few retries.
-                 */
-                udelay(3);
-        }
+        /*
+         * Poll PCC status register every 3us(delay_us) for maximum of
+         * deadline_us(timeout_us) until PCC command complete bit is set(cond)
+         */
+        ret = readw_relaxed_poll_timeout(&generic_comm_base->status, status,
+                                        status & PCC_CMD_COMPLETE_MASK, 3,
+                                        pcc_ss_data->deadline_us);
 
-        if (likely(!ret))
+        if (likely(!ret)) {
                 pcc_ss_data->platform_owns_pcc = false;
-        else
-                pr_err("PCC check channel failed for ss: %d. Status=%x\n",
-                       pcc_ss_id, status);
+                if (chk_err_bit && (status & PCC_ERROR_MASK))
+                        ret = -EIO;
+        }
+
+        if (unlikely(ret))
+                pr_err("PCC check channel failed for ss: %d. ret=%d\n",
+                       pcc_ss_id, ret);
 
         return ret;
 }
@@ -585,7 +575,7 @@ static int register_pcc_channel(int pcc_ss_idx)
                  * So add an arbitrary amount of wait on top of Nominal.
                  */
                 usecs_lat = NUM_RETRIES * cppc_ss->latency;
-                pcc_data[pcc_ss_idx]->deadline = ns_to_ktime(usecs_lat * NSEC_PER_USEC);
+                pcc_data[pcc_ss_idx]->deadline_us = usecs_lat;
                 pcc_data[pcc_ss_idx]->pcc_mrtt = cppc_ss->min_turnaround_time;
                 pcc_data[pcc_ss_idx]->pcc_mpar = cppc_ss->max_access_rate;
                 pcc_data[pcc_ss_idx]->pcc_nominal = cppc_ss->latency;