ACPI / CPPC: move all PCC related information into pcc_data
authorPrakash, Prashanth <pprakash@codeaurora.org>
Tue, 16 Aug 2016 20:39:43 +0000 (14:39 -0600)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tue, 30 Aug 2016 23:02:34 +0000 (01:02 +0200)
There are several global variables in cppc driver that are related
to PCC channel used for CPPC. This patch collects all such
information into a single consolidated structure(cppc_pcc_data).

Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/acpi/cppc_acpi.c

index f00fac3..80c123f 100644 (file)
 
 #include <acpi/cppc_acpi.h>
 
-/*
- * Lock to provide controlled access to the PCC channel.
- *
- * For performance critical usecases(currently cppc_set_perf)
- *     We need to take read_lock and check if channel belongs to OSPM before
- * reading or writing to PCC subspace
- *     We need to take write_lock before transferring the channel ownership to
- * the platform via a Doorbell
- *     This allows us to batch a number of CPPC requests if they happen to
- * originate in about the same time
- *
- * For non-performance critical usecases(init)
- *     Take write_lock for all purposes which gives exclusive access
- */
-static DECLARE_RWSEM(pcc_lock);
+struct cppc_pcc_data {
+       struct mbox_chan *pcc_channel;
+       void __iomem *pcc_comm_addr;
+       int pcc_subspace_idx;
+       bool pcc_channel_acquired;
+       ktime_t deadline;
+       unsigned int pcc_mpar, pcc_mrtt, pcc_nominal;
 
-/* Indicates if there are any pending/batched PCC write commands */
-static bool pending_pcc_write_cmd;
+       bool pending_pcc_write_cmd;     /* Any pending/batched PCC write cmds? */
+       unsigned int pcc_write_cnt;     /* Running count of PCC write commands */
 
-/* Wait queue for CPUs whose requests were batched */
-static DECLARE_WAIT_QUEUE_HEAD(pcc_write_wait_q);
+       /*
+        * Lock to provide controlled access to the PCC channel.
+        *
+        * For performance critical usecases(currently cppc_set_perf)
+        *      We need to take read_lock and check if channel belongs to OSPM
+        * before reading or writing to PCC subspace
+        *      We need to take write_lock before transferring the channel
+        * ownership to the platform via a Doorbell
+        *      This allows us to batch a number of CPPC requests if they happen
+        * to originate in about the same time
+        *
+        * For non-performance critical usecases(init)
+        *      Take write_lock for all purposes which gives exclusive access
+        */
+       struct rw_semaphore pcc_lock;
+
+       /* Wait queue for CPUs whose requests were batched */
+       wait_queue_head_t pcc_write_wait_q;
+};
 
-/* Used to identify if a batched request is delivered to platform */
-static unsigned int pcc_write_cnt;
+/* Structure to represent the single PCC channel */
+static struct cppc_pcc_data pcc_data = {
+       .pcc_subspace_idx = -1,
+};
 
 /*
  * The cpc_desc structure contains the ACPI register details
@@ -79,16 +90,8 @@ static unsigned int pcc_write_cnt;
  */
 static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
 
-/* This layer handles all the PCC specifics for CPPC. */
-static struct mbox_chan *pcc_channel;
-static void __iomem *pcc_comm_addr;
-static int pcc_subspace_idx = -1;
-static bool pcc_channel_acquired;
-static ktime_t deadline;
-static unsigned int pcc_mpar, pcc_mrtt, pcc_nominal;
-
 /* pcc mapped address + header size + offset within PCC subspace */
-#define GET_PCC_VADDR(offs) (pcc_comm_addr + 0x8 + (offs))
+#define GET_PCC_VADDR(offs) (pcc_data.pcc_comm_addr + 0x8 + (offs))
 
 /* Check if a CPC regsiter is in PCC */
 #define CPC_IN_PCC(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&            \
@@ -181,8 +184,8 @@ static struct kobj_type cppc_ktype = {
 static int check_pcc_chan(void)
 {
        int ret = -EIO;
-       struct acpi_pcct_shared_memory __iomem *generic_comm_base = pcc_comm_addr;
-       ktime_t next_deadline = ktime_add(ktime_get(), deadline);
+       struct acpi_pcct_shared_memory __iomem *generic_comm_base = pcc_data.pcc_comm_addr;
+       ktime_t next_deadline = ktime_add(ktime_get(), pcc_data.deadline);
 
        /* Retry in case the remote processor was too slow to catch up. */
        while (!ktime_after(ktime_get(), next_deadline)) {
@@ -213,7 +216,7 @@ static int send_pcc_cmd(u16 cmd)
 {
        int ret = -EIO, i;
        struct acpi_pcct_shared_memory *generic_comm_base =
-               (struct acpi_pcct_shared_memory *) pcc_comm_addr;
+               (struct acpi_pcct_shared_memory *) pcc_data.pcc_comm_addr;
        static ktime_t last_cmd_cmpl_time, last_mpar_reset;
        static int mpar_count;
        unsigned int time_delta;
@@ -228,24 +231,24 @@ static int send_pcc_cmd(u16 cmd)
                 * before write completion, so first send a WRITE command to
                 * platform
                 */
-               if (pending_pcc_write_cmd)
+               if (pcc_data.pending_pcc_write_cmd)
                        send_pcc_cmd(CMD_WRITE);
 
                ret = check_pcc_chan();
                if (ret)
                        goto end;
        } else /* CMD_WRITE */
-               pending_pcc_write_cmd = FALSE;
+               pcc_data.pending_pcc_write_cmd = FALSE;
 
        /*
         * Handle the Minimum Request Turnaround Time(MRTT)
         * "The minimum amount of time that OSPM must wait after the completion
         * of a command before issuing the next command, in microseconds"
         */
-       if (pcc_mrtt) {
+       if (pcc_data.pcc_mrtt) {
                time_delta = ktime_us_delta(ktime_get(), last_cmd_cmpl_time);
-               if (pcc_mrtt > time_delta)
-                       udelay(pcc_mrtt - time_delta);
+               if (pcc_data.pcc_mrtt > time_delta)
+                       udelay(pcc_data.pcc_mrtt - time_delta);
        }
 
        /*
@@ -259,7 +262,7 @@ static int send_pcc_cmd(u16 cmd)
         * not send the request to the platform after hitting the MPAR limit in
         * any 60s window
         */
-       if (pcc_mpar) {
+       if (pcc_data.pcc_mpar) {
                if (mpar_count == 0) {
                        time_delta = ktime_ms_delta(ktime_get(), last_mpar_reset);
                        if (time_delta < 60 * MSEC_PER_SEC) {
@@ -268,7 +271,7 @@ static int send_pcc_cmd(u16 cmd)
                                goto end;
                        }
                        last_mpar_reset = ktime_get();
-                       mpar_count = pcc_mpar;
+                       mpar_count = pcc_data.pcc_mpar;
                }
                mpar_count--;
        }
@@ -280,7 +283,7 @@ static int send_pcc_cmd(u16 cmd)
        writew_relaxed(0, &generic_comm_base->status);
 
        /* Ring doorbell */
-       ret = mbox_send_message(pcc_channel, &cmd);
+       ret = mbox_send_message(pcc_data.pcc_channel, &cmd);
        if (ret < 0) {
                pr_err("Err sending PCC mbox message. cmd:%d, ret:%d\n",
                                cmd, ret);
@@ -299,13 +302,13 @@ static int send_pcc_cmd(u16 cmd)
         * command for proper handling of MRTT, so we need to check
         * for pcc_mrtt in addition to CMD_READ
         */
-       if (cmd == CMD_READ || pcc_mrtt) {
+       if (cmd == CMD_READ || pcc_data.pcc_mrtt) {
                ret = check_pcc_chan();
-               if (pcc_mrtt)
+               if (pcc_data.pcc_mrtt)
                        last_cmd_cmpl_time = ktime_get();
        }
 
-       mbox_client_txdone(pcc_channel, ret);
+       mbox_client_txdone(pcc_data.pcc_channel, ret);
 
 end:
        if (cmd == CMD_WRITE) {
@@ -315,12 +318,12 @@ end:
                                if (!desc)
                                        continue;
 
-                               if (desc->write_cmd_id == pcc_write_cnt)
+                               if (desc->write_cmd_id == pcc_data.pcc_write_cnt)
                                        desc->write_cmd_status = ret;
                        }
                }
-               pcc_write_cnt++;
-               wake_up_all(&pcc_write_wait_q);
+               pcc_data.pcc_write_cnt++;
+               wake_up_all(&pcc_data.pcc_write_wait_q);
        }
 
        return ret;
@@ -528,10 +531,10 @@ static int register_pcc_channel(int pcc_subspace_idx)
        u64 usecs_lat;
 
        if (pcc_subspace_idx >= 0) {
-               pcc_channel = pcc_mbox_request_channel(&cppc_mbox_cl,
+               pcc_data.pcc_channel = pcc_mbox_request_channel(&cppc_mbox_cl,
                                pcc_subspace_idx);
 
-               if (IS_ERR(pcc_channel)) {
+               if (IS_ERR(pcc_data.pcc_channel)) {
                        pr_err("Failed to find PCC communication channel\n");
                        return -ENODEV;
                }
@@ -542,7 +545,7 @@ static int register_pcc_channel(int pcc_subspace_idx)
                 * PCC channels) and stored pointers to the
                 * subspace communication region in con_priv.
                 */
-               cppc_ss = pcc_channel->con_priv;
+               cppc_ss = (pcc_data.pcc_channel)->con_priv;
 
                if (!cppc_ss) {
                        pr_err("No PCC subspace found for CPPC\n");
@@ -555,19 +558,19 @@ static int register_pcc_channel(int pcc_subspace_idx)
                 * So add an arbitrary amount of wait on top of Nominal.
                 */
                usecs_lat = NUM_RETRIES * cppc_ss->latency;
-               deadline = ns_to_ktime(usecs_lat * NSEC_PER_USEC);
-               pcc_mrtt = cppc_ss->min_turnaround_time;
-               pcc_mpar = cppc_ss->max_access_rate;
-               pcc_nominal = cppc_ss->latency;
+               pcc_data.deadline = ns_to_ktime(usecs_lat * NSEC_PER_USEC);
+               pcc_data.pcc_mrtt = cppc_ss->min_turnaround_time;
+               pcc_data.pcc_mpar = cppc_ss->max_access_rate;
+               pcc_data.pcc_nominal = cppc_ss->latency;
 
-               pcc_comm_addr = acpi_os_ioremap(cppc_ss->base_address, cppc_ss->length);
-               if (!pcc_comm_addr) {
+               pcc_data.pcc_comm_addr = acpi_os_ioremap(cppc_ss->base_address, cppc_ss->length);
+               if (!pcc_data.pcc_comm_addr) {
                        pr_err("Failed to ioremap PCC comm region mem\n");
                        return -ENOMEM;
                }
 
                /* Set flag so that we dont come here for each CPU. */
-               pcc_channel_acquired = true;
+               pcc_data.pcc_channel_acquired = true;
        }
 
        return 0;
@@ -706,9 +709,9 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
                         * so extract it only once.
                         */
                        if (gas_t->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
-                               if (pcc_subspace_idx < 0)
-                                       pcc_subspace_idx = gas_t->access_width;
-                               else if (pcc_subspace_idx != gas_t->access_width) {
+                               if (pcc_data.pcc_subspace_idx < 0)
+                                       pcc_data.pcc_subspace_idx = gas_t->access_width;
+                               else if (pcc_data.pcc_subspace_idx != gas_t->access_width) {
                                        pr_debug("Mismatched PCC ids.\n");
                                        goto out_free;
                                }
@@ -743,10 +746,13 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
                goto out_free;
 
        /* Register PCC channel once for all CPUs. */
-       if (!pcc_channel_acquired) {
-               ret = register_pcc_channel(pcc_subspace_idx);
+       if (!pcc_data.pcc_channel_acquired) {
+               ret = register_pcc_channel(pcc_data.pcc_subspace_idx);
                if (ret)
                        goto out_free;
+
+               init_rwsem(&pcc_data.pcc_lock);
+               init_waitqueue_head(&pcc_data.pcc_write_wait_q);
        }
 
        /* Plug PSD data into this CPUs CPC descriptor. */
@@ -924,7 +930,7 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
        if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
                CPC_IN_PCC(ref_perf) || CPC_IN_PCC(nom_perf)) {
                regs_in_pcc = 1;
-               down_write(&pcc_lock);
+               down_write(&pcc_data.pcc_lock);
                /* Ring doorbell once to update PCC subspace */
                if (send_pcc_cmd(CMD_READ) < 0) {
                        ret = -EIO;
@@ -946,7 +952,7 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 
 out_err:
        if (regs_in_pcc)
-               up_write(&pcc_lock);
+               up_write(&pcc_data.pcc_lock);
        return ret;
 }
 EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
@@ -986,7 +992,7 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
        /* Are any of the regs PCC ?*/
        if (CPC_IN_PCC(delivered_reg) || CPC_IN_PCC(reference_reg) ||
                CPC_IN_PCC(ctr_wrap_reg) || CPC_IN_PCC(ref_perf_reg)) {
-               down_write(&pcc_lock);
+               down_write(&pcc_data.pcc_lock);
                regs_in_pcc = 1;
                /* Ring doorbell once to update PCC subspace */
                if (send_pcc_cmd(CMD_READ) < 0) {
@@ -1019,7 +1025,7 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
        perf_fb_ctrs->ctr_wrap_time = ctr_wrap_time;
 out_err:
        if (regs_in_pcc)
-               up_write(&pcc_lock);
+               up_write(&pcc_data.pcc_lock);
        return ret;
 }
 EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
@@ -1052,17 +1058,17 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
         * achieve that goal here
         */
        if (CPC_IN_PCC(desired_reg)) {
-               down_read(&pcc_lock);   /* BEGIN Phase-I */
+               down_read(&pcc_data.pcc_lock);  /* BEGIN Phase-I */
                /*
                 * If there are pending write commands i.e pending_pcc_write_cmd
                 * is TRUE, then we know OSPM owns the channel as another CPU
                 * has already checked for command completion bit and updated
                 * the corresponding CPC registers
                 */
-               if (!pending_pcc_write_cmd) {
+               if (!pcc_data.pending_pcc_write_cmd) {
                        ret = check_pcc_chan();
                        if (ret) {
-                               up_read(&pcc_lock);
+                               up_read(&pcc_data.pcc_lock);
                                return ret;
                        }
                        /*
@@ -1070,9 +1076,9 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
                         * will not arrive and steal the channel during the
                         * transition to write lock
                         */
-                       pending_pcc_write_cmd = TRUE;
+                       pcc_data.pending_pcc_write_cmd = TRUE;
                }
-               cpc_desc->write_cmd_id = pcc_write_cnt;
+               cpc_desc->write_cmd_id = pcc_data.pcc_write_cnt;
                cpc_desc->write_cmd_status = 0;
        }
 
@@ -1083,7 +1089,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
        cpc_write(desired_reg, perf_ctrls->desired_perf);
 
        if (CPC_IN_PCC(desired_reg))
-               up_read(&pcc_lock);     /* END Phase-I */
+               up_read(&pcc_data.pcc_lock);    /* END Phase-I */
        /*
         * This is Phase-II where we transfer the ownership of PCC to Platform
         *
@@ -1131,15 +1137,15 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
         * the write command before servicing the read command
         */
        if (CPC_IN_PCC(desired_reg)) {
-               if (down_write_trylock(&pcc_lock)) {            /* BEGIN Phase-II */
+               if (down_write_trylock(&pcc_data.pcc_lock)) {   /* BEGIN Phase-II */
                        /* Update only if there are pending write commands */
-                       if (pending_pcc_write_cmd)
+                       if (pcc_data.pending_pcc_write_cmd)
                                send_pcc_cmd(CMD_WRITE);
-                       up_write(&pcc_lock);                    /* END Phase-II */
+                       up_write(&pcc_data.pcc_lock);           /* END Phase-II */
                } else
                        /* Wait until pcc_write_cnt is updated by send_pcc_cmd */
-                       wait_event(pcc_write_wait_q,
-                               cpc_desc->write_cmd_id != pcc_write_cnt);
+                       wait_event(pcc_data.pcc_write_wait_q,
+                               cpc_desc->write_cmd_id != pcc_data.pcc_write_cnt);
 
                /* send_pcc_cmd updates the status in case of failure */
                ret = cpc_desc->write_cmd_status;
@@ -1181,10 +1187,11 @@ unsigned int cppc_get_transition_latency(int cpu_num)
        if (!CPC_IN_PCC(desired_reg))
                return CPUFREQ_ETERNAL;
 
-       if (pcc_mpar)
-               latency_ns = 60 * (1000 * 1000 * 1000 / pcc_mpar);
+       if (pcc_data.pcc_mpar)
+               latency_ns = 60 * (1000 * 1000 * 1000 / pcc_data.pcc_mpar);
 
-       latency_ns = max(latency_ns, (pcc_nominal + pcc_mrtt) * 1000);
+       latency_ns = max(latency_ns, pcc_data.pcc_nominal * 1000);
+       latency_ns = max(latency_ns, pcc_data.pcc_mrtt * 1000);
 
        return latency_ns;
 }