misc: pch_phub: Read prefetch value from device tree if passed

The default prefetch value for the eg20t device is hard coded to
0x000affaa.

Add support for an alternative to be read from DT if available

Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/pch_phub.c b/drivers/misc/pch_phub.c
index 4810e039bbeced8bd7bb337ddd6404c95b3bfdd6..1dd18f500730f601755724d4e0b8550854dd09ad 100644 (file)
--- a/drivers/misc/pch_phub.c
+++ b/drivers/misc/pch_phub.c
@@ -28,6 +28,7 @@
 #include <linux/if_ether.h>
 #include <linux/ctype.h>
 #include <linux/dmi.h>
+#include <linux/of.h>
 
 #define PHUB_STATUS 0x00               /* Status Register offset */
 #define PHUB_CONTROL 0x04              /* Control Register offset */
@@ -711,6 +712,12 @@ static int pch_phub_probe(struct pci_dev *pdev,
 
        if (id->driver_data == 1) { /* EG20T PCH */
                const char *board_name;
+               unsigned int prefetch = 0x000affaa;
+
+               if (pdev->dev.of_node)
+                       of_property_read_u32(pdev->dev.of_node,
+                                                 "intel,eg20t-prefetch",
+                                                 &prefetch);
 
                ret = sysfs_create_file(&pdev->dev.kobj,
                                        &dev_attr_pch_mac.attr);
@@ -736,7 +743,7 @@ static int pch_phub_probe(struct pci_dev *pdev,
                                                CLKCFG_UART_MASK);
 
                /* set the prefech value */
-               iowrite32(0x000affaa, chip->pch_phub_base_address + 0x14);
+               iowrite32(prefetch, chip->pch_phub_base_address + 0x14);
                /* set the interrupt delay value */
                iowrite32(0x25, chip->pch_phub_base_address + 0x44);
                chip->pch_opt_rom_start_address = PCH_PHUB_ROM_START_ADDR_EG20T;