clk-bcm2835: Add claim-clocks property

The claim-clocks property can be used to prevent PLLs and dividers
from being marked as critical. It contains a vector of clock IDs,
as defined by dt-bindings/clock/bcm2835.h.

Use this mechanism to claim PLLD_DSI0, PLLD_DSI1, PLLH_AUX and
PLLH_PIX for the vc4_kms_v3d driver.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 0f716cb..50f018f 100644 (file)
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1312,6 +1312,8 @@ static const struct clk_ops bcm2835_vpu_clock_clk_ops = {
        .debug_init = bcm2835_clock_debug_init,
 };
 
+static bool bcm2835_clk_is_claimed(const char *name);
+
 static struct clk_hw *bcm2835_register_pll(struct bcm2835_cprman *cprman,
                                           const void *data)
 {
@@ -1329,6 +1331,9 @@ static struct clk_hw *bcm2835_register_pll(struct bcm2835_cprman *cprman,
        init.ops = &bcm2835_pll_clk_ops;
        init.flags = pll_data->flags | CLK_IGNORE_UNUSED;
 
+       if (!bcm2835_clk_is_claimed(pll_data->name))
+               init.flags |= CLK_IS_CRITICAL;
+
        pll = kzalloc(sizeof(*pll), GFP_KERNEL);
        if (!pll)
                return NULL;
@@ -1384,9 +1389,11 @@ bcm2835_register_pll_divider(struct bcm2835_cprman *cprman,
        divider->div.hw.init = &init;
        divider->div.table = NULL;
 
-       if (!(cprman_read(cprman, data->cm_reg) & data->hold_mask)) {
-               init.flags |= CLK_IS_CRITICAL;
-               divider->div.flags |= CLK_IS_CRITICAL;
+       if (!(cprman_read(cprman, divider_data->cm_reg) & divider_data->hold_mask)) {
+               if (!bcm2835_clk_is_claimed(divider_data->source_pll))
+                       init.flags |= CLK_IS_CRITICAL;
+               if (!bcm2835_clk_is_claimed(divider_data->name))
+                       divider->div.flags |= CLK_IS_CRITICAL;
        }
 
        divider->cprman = cprman;
@@ -1443,6 +1450,15 @@ static struct clk_hw *bcm2835_register_clock(struct bcm2835_cprman *cprman,
        init.flags = clock_data->flags | CLK_IGNORE_UNUSED;
 
        /*
+        * Some GPIO clocks for ethernet/wifi PLLs are marked as
+        * critical (since some platforms use them), but if the
+        * firmware didn't have them turned on then they clearly
+        * aren't actually critical.
+        */
+       if ((cprman_read(cprman, clock_data->ctl_reg) & CM_ENABLE) == 0)
+               init.flags &= ~CLK_IS_CRITICAL;
+
+       /*
         * Pass the CLK_SET_RATE_PARENT flag if we are allowed to propagate
         * rate changes on at least of the parents.
         */
@@ -2221,6 +2237,8 @@ static const struct bcm2835_clk_desc clk_desc_array[] = {
                .ctl_reg = CM_PERIICTL),
 };
 
+static bool bcm2835_clk_claimed[ARRAY_SIZE(clk_desc_array)];
+
 /*
  * Permanently take a reference on the parent of the SDRAM clock.
  *
@@ -2240,6 +2258,19 @@ static int bcm2835_mark_sdc_parent_critical(struct clk *sdc)
        return clk_prepare_enable(parent);
 }
 
+static bool bcm2835_clk_is_claimed(const char *name)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(clk_desc_array); i++) {
+               const char *clk_name = *(const char **)(clk_desc_array[i].data);
+               if (!strcmp(name, clk_name))
+                   return bcm2835_clk_claimed[i];
+       }
+
+       return false;
+}
+
 static int bcm2835_clk_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
@@ -2249,6 +2280,7 @@ static int bcm2835_clk_probe(struct platform_device *pdev)
        const size_t asize = ARRAY_SIZE(clk_desc_array);
        const struct cprman_plat_data *pdata;
        size_t i;
+       u32 clk_id;
        int ret;
 
        pdata = of_device_get_match_data(&pdev->dev);
@@ -2267,6 +2299,13 @@ static int bcm2835_clk_probe(struct platform_device *pdev)
        if (IS_ERR(cprman->regs))
                return PTR_ERR(cprman->regs);
 
+       memset(bcm2835_clk_claimed, 0, sizeof(bcm2835_clk_claimed));
+       for (i = 0;
+            !of_property_read_u32_index(pdev->dev.of_node, "claim-clocks",
+                                        i, &clk_id);
+            i++)
+               bcm2835_clk_claimed[clk_id]= true;
+
        memcpy(cprman->real_parent_names, cprman_parent_names,
               sizeof(cprman_parent_names));
        of_clk_parent_fill(dev->of_node, cprman->real_parent_names,