clk: x86: Add system specific quirk to mark clocks as critical

Since commit 648e921888ad ("clk: x86: Stop marking clocks as
CLK_IS_CRITICAL"), the pmc_plt_clocks of the Bay Trail SoC are
unconditionally gated off. Unfortunately this will break systems where these
clocks are used for external purposes beyond the kernel's knowledge. Fix it
by implementing a system specific quirk to mark the necessary pmc_plt_clks as
critical.

Fixes: 648e921888ad ("clk: x86: Stop marking clocks as CLK_IS_CRITICAL")
Signed-off-by: David Müller <dave.mueller@gmx.ch>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/clk/x86/clk-pmc-atom.c b/drivers/clk/x86/clk-pmc-atom.c
index d977193842df..19174835693b 100644
--- a/drivers/clk/x86/clk-pmc-atom.c
+++ b/drivers/clk/x86/clk-pmc-atom.c
@@ -165,7 +165,7 @@ static const struct clk_ops plt_clk_ops = {
 };
 
 static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
-                                        void __iomem *base,
+                                        const struct pmc_clk_data *pmc_data,
                                         const char **parent_names,
                                         int num_parents)
 {
@@ -184,9 +184,17 @@ static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
         init.num_parents = num_parents;
 
         pclk->hw.init = &init;
-        pclk->reg = base + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE;
+        pclk->reg = pmc_data->base + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE;
         spin_lock_init(&pclk->lock);
 
+        /*
+         * On some systems, the pmc_plt_clocks already enabled by the
+         * firmware are being marked as critical to avoid them being
+         * gated by the clock framework.
+         */
+        if (pmc_data->critical && plt_clk_is_enabled(&pclk->hw))
+                init.flags |= CLK_IS_CRITICAL;
+
         ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
         if (ret) {
                 pclk = ERR_PTR(ret);
@@ -332,7 +340,7 @@ static int plt_clk_probe(struct platform_device *pdev)
                 return PTR_ERR(parent_names);
 
         for (i = 0; i < PMC_CLK_NUM; i++) {
-                data->clks[i] = plt_clk_register(pdev, i, pmc_data->base,
+                data->clks[i] = plt_clk_register(pdev, i, pmc_data,
                                                  parent_names, data->nparents);
                 if (IS_ERR(data->clks[i])) {
                         err = PTR_ERR(data->clks[i]);