UBUNTU: SAUCE: mfd: intel-lpss: add quirk for Dell XPS 13 7390 2-in-1

BugLink: https://bugs.launchpad.net/bugs/1845584
The memory region intel-lpss-pci uses has been declared as
write-combining
[    0.001728]   5 base 4000000000 mask 6000000000 write-combining
This leads to the system hangs up during booting up.

Tuowen Zhao(ztuowen@gmail.com) provides a diff patch for intel-lpss
driver to claim to use un-cacheable memory while calling
__devm_ioremap(), and it works well. But it haven't been accepted by
maintainer yet.

To avoid the potential impact on other machines, I add a quirk to list
the machines which has the write-combining area in MTRR which overlaps
with the address that intel-lpss uses, only the machines in the list
pass the DEVM_IOREMAP_UC to __devm_ioremap().

Link: https://bugzilla.kernel.org/show_bug.cgi?id=203485
Signed-off-by: AceLan Kao <acelan.kao@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Paolo Pisati <paolo.pisati@canonical.com>
Acked-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/mfd/intel-lpss.c b/drivers/mfd/intel-lpss.c
index b5c4f8f974aa75882f6e64dc0d7a7b6ac193210c..94e6d675eac047b37ad0202772f718f48318eea6 100644 (file)
--- a/drivers/mfd/intel-lpss.c
+++ b/drivers/mfd/intel-lpss.c
@@ -17,6 +17,7 @@
 #include <linux/clkdev.h>
 #include <linux/clk-provider.h>
 #include <linux/debugfs.h>
+#include <linux/dmi.h>
 #include <linux/idr.h>
 #include <linux/ioport.h>
 #include <linux/kernel.h>
@@ -130,6 +131,17 @@ static const struct mfd_cell intel_lpss_spi_cell = {
 static DEFINE_IDA(intel_lpss_devid_ida);
 static struct dentry *intel_lpss_debugfs;
 
+static const struct dmi_system_id mtrr_large_wc_region[] = {
+       {
+               .ident = "Dell Computer Corporation",
+               .matches = {
+                       DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+                       DMI_MATCH(DMI_PRODUCT_NAME, "XPS 13 7390 2-in-1"),
+               },
+       },
+       { }
+};
+
 static int intel_lpss_request_dma_module(const char *name)
 {
        static bool intel_lpss_dma_requested;
@@ -397,8 +409,12 @@ int intel_lpss_probe(struct device *dev,
        if (!lpss)
                return -ENOMEM;
 
-       lpss->priv = devm_ioremap(dev, info->mem->start + LPSS_PRIV_OFFSET,
-                                 LPSS_PRIV_SIZE);
+       if (dmi_check_system(mtrr_large_wc_region))
+               lpss->priv = devm_ioremap_uc(dev, info->mem->start + LPSS_PRIV_OFFSET,
+                                            LPSS_PRIV_SIZE);
+       else
+               lpss->priv = devm_ioremap(dev, info->mem->start + LPSS_PRIV_OFFSET,
+                                         LPSS_PRIV_SIZE);
        if (!lpss->priv)
                return -ENOMEM;
 

diff --git a/include/linux/io.h b/include/linux/io.h
index 32e30e8fb9db92cf1472c6188ff3310a610b3c5f..da39ff89df65164548cbe2f4a1ccab91301b167e 100644 (file)
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -75,6 +75,8 @@ static inline void devm_ioport_unmap(struct device *dev, void __iomem *addr)
 
 void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
                           resource_size_t size);
+void __iomem *devm_ioremap_uc(struct device *dev, resource_size_t offset,
+                                  resource_size_t size);
 void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
                                   resource_size_t size);
 void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset,

diff --git a/lib/devres.c b/lib/devres.c
index 5f2aedd58bc5032eb18e882fbb2e539f0feed550..d5286472fcbc36b16fa8ff85ae4978e1157e2129 100644 (file)
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -43,6 +43,35 @@ void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
 }
 EXPORT_SYMBOL(devm_ioremap);
 
+/**
+ * devm_ioremap_uc - Managed ioremap_uc()
+ * @dev: Generic device to remap IO address for
+ * @offset: Resource address to map
+ * @size: Size of map
+ *
+ * Managed ioremap_uc().  Map is automatically unmapped on driver detach.
+ */
+void __iomem *devm_ioremap_uc(struct device *dev, resource_size_t offset,
+                             resource_size_t size)
+{
+       void __iomem **ptr, *addr;
+
+       ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
+       if (!ptr)
+               return NULL;
+
+       addr = ioremap_uc(offset, size);
+       if (addr) {
+               *ptr = addr;
+               devres_add(dev, ptr);
+       } else
+               devres_free(ptr);
+
+       return addr;
+}
+EXPORT_SYMBOL(devm_ioremap_uc);
+
+
 /**
  * devm_ioremap_nocache - Managed ioremap_nocache()
  * @dev: Generic device to remap IO address for