hwmon: (dimmtemp) Support more than 32 DIMMs

This patch introduces support for handling more than 32 DIMMs by
utilizing bitmap operations. The changes ensure that the driver can
handle a higher number of DIMMs efficiently.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Link: https://lore.kernel.org/r/20230711152144.755177-1-Naresh.Solanki@9elements.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/peci/dimmtemp.c b/drivers/hwmon/peci/dimmtemp.c
index ed96840..ce89da3 100644 (file)
--- a/drivers/hwmon/peci/dimmtemp.c
+++ b/drivers/hwmon/peci/dimmtemp.c
@@ -219,19 +219,21 @@ static int check_populated_dimms(struct peci_dimmtemp *priv)
 {
        int chan_rank_max = priv->gen_info->chan_rank_max;
        int dimm_idx_max = priv->gen_info->dimm_idx_max;
-       u32 chan_rank_empty = 0;
-       u32 dimm_mask = 0;
-       int chan_rank, dimm_idx, ret;
+       DECLARE_BITMAP(dimm_mask, DIMM_NUMS_MAX);
+       DECLARE_BITMAP(chan_rank_empty, CHAN_RANK_MAX);
+
+       int chan_rank, dimm_idx, ret, i;
        u32 pcs;
 
-       BUILD_BUG_ON(BITS_PER_TYPE(chan_rank_empty) < CHAN_RANK_MAX);
-       BUILD_BUG_ON(BITS_PER_TYPE(dimm_mask) < DIMM_NUMS_MAX);
        if (chan_rank_max * dimm_idx_max > DIMM_NUMS_MAX) {
                WARN_ONCE(1, "Unsupported number of DIMMs - chan_rank_max: %d, dimm_idx_max: %d",
                          chan_rank_max, dimm_idx_max);
                return -EINVAL;
        }
 
+       bitmap_zero(dimm_mask, DIMM_NUMS_MAX);
+       bitmap_zero(chan_rank_empty, CHAN_RANK_MAX);
+
        for (chan_rank = 0; chan_rank < chan_rank_max; chan_rank++) {
                ret = peci_pcs_read(priv->peci_dev, PECI_PCS_DDR_DIMM_TEMP, chan_rank, &pcs);
                if (ret) {
@@ -242,7 +244,7 @@ static int check_populated_dimms(struct peci_dimmtemp *priv)
                         * detection to be performed at a later point in time.
                         */
                        if (ret == -EINVAL) {
-                               chan_rank_empty |= BIT(chan_rank);
+                               bitmap_set(chan_rank_empty, chan_rank, 1);
                                continue;
                        }
 
@@ -251,7 +253,7 @@ static int check_populated_dimms(struct peci_dimmtemp *priv)
 
                for (dimm_idx = 0; dimm_idx < dimm_idx_max; dimm_idx++)
                        if (__dimm_temp(pcs, dimm_idx))
-                               dimm_mask |= BIT(chan_rank * dimm_idx_max + dimm_idx);
+                               bitmap_set(dimm_mask, chan_rank * dimm_idx_max + dimm_idx, 1);
        }
 
        /*
@@ -260,7 +262,7 @@ static int check_populated_dimms(struct peci_dimmtemp *priv)
         * host platform boot. Retrying a couple of times lets us make sure
         * that the state is persistent.
         */
-       if (chan_rank_empty == GENMASK(chan_rank_max - 1, 0)) {
+       if (bitmap_full(chan_rank_empty, chan_rank_max)) {
                if (priv->no_dimm_retry_count < NO_DIMM_RETRY_COUNT_MAX) {
                        priv->no_dimm_retry_count++;
 
@@ -274,14 +276,16 @@ static int check_populated_dimms(struct peci_dimmtemp *priv)
         * It's possible that memory training is not done yet. In this case we
         * defer the detection to be performed at a later point in time.
         */
-       if (!dimm_mask) {
+       if (bitmap_empty(dimm_mask, DIMM_NUMS_MAX)) {
                priv->no_dimm_retry_count = 0;
                return -EAGAIN;
        }
 
-       dev_dbg(priv->dev, "Scanned populated DIMMs: %#x\n", dimm_mask);
+       for_each_set_bit(i, dimm_mask, DIMM_NUMS_MAX) {
+               dev_dbg(priv->dev, "Found DIMM%#x\n", i);
+       }
 
-       bitmap_from_arr32(priv->dimm_mask, &dimm_mask, DIMM_NUMS_MAX);
+       bitmap_copy(priv->dimm_mask, dimm_mask, DIMM_NUMS_MAX);
 
        return 0;
 }