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, 21 insertions, 0 deletions

diff --git a/drivers/platform/x86/pmc_atom.c b/drivers/platform/x86/pmc_atom.c
index 8f018b3f3cd4..eaec2d306481 100644
--- a/drivers/platform/x86/pmc_atom.c
+++ b/drivers/platform/x86/pmc_atom.c
@@ -17,6 +17,7 @@
 
 #include <linux/debugfs.h>
 #include <linux/device.h>
+#include <linux/dmi.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/platform_data/x86/clk-pmc-atom.h>
@@ -391,11 +392,27 @@ static int pmc_dbgfs_register(struct pmc_dev *pmc)
 }
 #endif /* CONFIG_DEBUG_FS */
 
+/*
+ * Some systems need one or more of their pmc_plt_clks to be
+ * marked as critical.
+ */
+static const struct dmi_system_id critclk_systems[] __initconst = {
+        {
+                .ident = "MPL CEC1x",
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "MPL AG"),
+                        DMI_MATCH(DMI_PRODUCT_NAME, "CEC10 Family"),
+                },
+        },
+        { /*sentinel*/ }
+};
+
 static int pmc_setup_clks(struct pci_dev *pdev, void __iomem *pmc_regmap,
                           const struct pmc_data *pmc_data)
 {
         struct platform_device *clkdev;
         struct pmc_clk_data *clk_data;
+        const struct dmi_system_id *d = dmi_first_match(critclk_systems);
 
         clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
         if (!clk_data)
@@ -403,6 +420,10 @@ static int pmc_setup_clks(struct pci_dev *pdev, void __iomem *pmc_regmap,
 
         clk_data->base = pmc_regmap; /* offset is added by client */
         clk_data->clks = pmc_data->clks;
+        if (d) {
+                clk_data->critical = true;
+                pr_info("%s critclks quirk enabled\n", d->ident);
+        }
 
         clkdev = platform_device_register_data(&pdev->dev, "clk-pmc-atom",
                                                PLATFORM_DEVID_NONE,