net: mscc: ocelot: make access to STAT_VIEW sleepable again

To support SPI-controlled switches in the future, access to
SYS_STAT_CFG_STAT_VIEW needs to be done outside of any spinlock
protected region, but it still needs to be serialized (by a mutex).

Split the ocelot->stats_lock spinlock into a mutex that serializes
indirect access to hardware registers (ocelot->stat_view_lock) and a
spinlock that serializes access to the u64 ocelot->stats array.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c
index 3c80df4..858ccf1 100644 (file)
--- a/drivers/net/dsa/ocelot/felix_vsc9959.c
+++ b/drivers/net/dsa/ocelot/felix_vsc9959.c
@@ -2574,7 +2574,7 @@ static void vsc9959_psfp_sgi_table_del(struct ocelot *ocelot,
 static void vsc9959_psfp_counters_get(struct ocelot *ocelot, u32 index,
                                      struct felix_stream_filter_counters *counters)
 {
-       spin_lock(&ocelot->stats_lock);
+       mutex_lock(&ocelot->stat_view_lock);
 
        ocelot_rmw(ocelot, SYS_STAT_CFG_STAT_VIEW(index),
                   SYS_STAT_CFG_STAT_VIEW_M,
@@ -2593,7 +2593,7 @@ static void vsc9959_psfp_counters_get(struct ocelot *ocelot, u32 index,
                     SYS_STAT_CFG_STAT_CLEAR_SHOT(0x10),
                     SYS_STAT_CFG);
 
-       spin_unlock(&ocelot->stats_lock);
+       mutex_unlock(&ocelot->stat_view_lock);
 }
 
 static int vsc9959_psfp_filter_add(struct ocelot *ocelot, int port,

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index dddaffd..a677a18 100644 (file)
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1870,12 +1870,13 @@ void ocelot_get_strings(struct ocelot *ocelot, int port, u32 sset, u8 *data)
 }
 EXPORT_SYMBOL(ocelot_get_strings);
 
-/* Caller must hold &ocelot->stats_lock */
+/* Read the counters from hardware and keep them in region->buf.
+ * Caller must hold &ocelot->stat_view_lock.
+ */
 static int ocelot_port_update_stats(struct ocelot *ocelot, int port)
 {
-       unsigned int idx = port * OCELOT_NUM_STATS;
        struct ocelot_stats_region *region;
-       int err, j;
+       int err;
 
        /* Configure the port to read the stats from */
        ocelot_write(ocelot, SYS_STAT_CFG_STAT_VIEW(port), SYS_STAT_CFG);
@@ -1885,7 +1886,21 @@ static int ocelot_port_update_stats(struct ocelot *ocelot, int port)
                                       region->count);
                if (err)
                        return err;
+       }
+
+       return 0;
+}
 
+/* Transfer the counters from region->buf to ocelot->stats.
+ * Caller must hold &ocelot->stat_view_lock and &ocelot->stats_lock.
+ */
+static void ocelot_port_transfer_stats(struct ocelot *ocelot, int port)
+{
+       unsigned int idx = port * OCELOT_NUM_STATS;
+       struct ocelot_stats_region *region;
+       int j;
+
+       list_for_each_entry(region, &ocelot->stats_regions, node) {
                for (j = 0; j < region->count; j++) {
                        u64 *stat = &ocelot->stats[idx + j];
                        u64 val = region->buf[j];
@@ -1898,8 +1913,6 @@ static int ocelot_port_update_stats(struct ocelot *ocelot, int port)
 
                idx += region->count;
        }
-
-       return err;
 }
 
 static void ocelot_check_stats_work(struct work_struct *work)
@@ -1907,15 +1920,21 @@ static void ocelot_check_stats_work(struct work_struct *work)
        struct delayed_work *del_work = to_delayed_work(work);
        struct ocelot *ocelot = container_of(del_work, struct ocelot,
                                             stats_work);
-       int i, err;
+       int port, err;
 
-       spin_lock(&ocelot->stats_lock);
-       for (i = 0; i < ocelot->num_phys_ports; i++) {
-               err = ocelot_port_update_stats(ocelot, i);
+       mutex_lock(&ocelot->stat_view_lock);
+
+       for (port = 0; port < ocelot->num_phys_ports; port++) {
+               err = ocelot_port_update_stats(ocelot, port);
                if (err)
                        break;
+
+               spin_lock(&ocelot->stats_lock);
+               ocelot_port_transfer_stats(ocelot, port);
+               spin_unlock(&ocelot->stats_lock);
        }
-       spin_unlock(&ocelot->stats_lock);
+
+       mutex_unlock(&ocelot->stat_view_lock);
 
        if (err)
                dev_err(ocelot->dev, "Error %d updating ethtool stats\n",  err);
@@ -1928,11 +1947,15 @@ void ocelot_get_ethtool_stats(struct ocelot *ocelot, int port, u64 *data)
 {
        int i, err;
 
-       spin_lock(&ocelot->stats_lock);
+       mutex_lock(&ocelot->stat_view_lock);
 
        /* check and update now */
        err = ocelot_port_update_stats(ocelot, port);
 
+       spin_lock(&ocelot->stats_lock);
+
+       ocelot_port_transfer_stats(ocelot, port);
+
        /* Copy all supported counters */
        for (i = 0; i < OCELOT_NUM_STATS; i++) {
                int index = port * OCELOT_NUM_STATS + i;
@@ -1945,6 +1968,8 @@ void ocelot_get_ethtool_stats(struct ocelot *ocelot, int port, u64 *data)
 
        spin_unlock(&ocelot->stats_lock);
 
+       mutex_unlock(&ocelot->stat_view_lock);
+
        if (err)
                dev_err(ocelot->dev, "Error %d updating ethtool stats\n", err);
 }
@@ -3396,6 +3421,7 @@ int ocelot_init(struct ocelot *ocelot)
                return -ENOMEM;
 
        spin_lock_init(&ocelot->stats_lock);
+       mutex_init(&ocelot->stat_view_lock);
        mutex_init(&ocelot->ptp_lock);
        mutex_init(&ocelot->mact_lock);
        mutex_init(&ocelot->fwd_domain_lock);

diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index 99d6792..e85fb3b 100644 (file)
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -901,12 +901,15 @@ struct ocelot {
 
        struct ocelot_psfp_list         psfp;
 
-       /* Workqueue to check statistics for overflow with its lock */
-       spinlock_t                      stats_lock;
-       u64                             *stats;
+       /* Workqueue to check statistics for overflow */
        struct delayed_work             stats_work;
        struct workqueue_struct         *stats_queue;
+       /* Lock for serializing access to the statistics array */
+       spinlock_t                      stats_lock;
+       u64                             *stats;
 
+       /* Lock for serializing indirect access to STAT_VIEW registers */
+       struct mutex                    stat_view_lock;
        /* Lock for serializing access to the MAC table */
        struct mutex                    mact_lock;
        /* Lock for serializing forwarding domain changes */