@@ -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? */
@@ -193,42 +194,31 @@ 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;
}
@@ -580,7 +570,7 @@ 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;