clk-bcm2835: Mark used PLLs and dividers CRITICAL

raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------

The VPU configures and relies on several PLLs and dividers. Mark all
enabled dividers and their PLLs as CRITICAL to prevent the kernel from
switching them off.
Signed-off-by: NPhil Elwell <phil@raspberrypi.org>
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/clk/bcm/clk-bcm2835.c

@@ -1384,6 +1384,11 @@ 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;
+	}
+
 	divider->cprman = cprman;
 	divider->data = divider_data;