soc/intel/fsp_broadwell_de: Add function to set DPR

Add code for FSP Broadwell DE to set the DPR.
Used by the Intel TXT code.

Tested on Intel Broadwell DE using Intel TXT.

Change-Id: Ib5e1ba8731e5cea1be9319a1fb9658dba841dc7b
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36226
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>

src/soc/intel/fsp_broadwell_de/include/soc/broadwell_de.h

@@ -31,6 +31,15 @@ size_t sa_get_tseg_size(void);
 #define TSEG_BASE		0xa8	/* TSEG base */
 #define TSEG_LIMIT		0xac	/* TSEG limit */
 
+#define IIO_LTDPR		0x290
+#define  DPR_LOCK	(1 << 0)
+#define  DPR_EPM	(1 << 2)
+#define  DPR_PRS	(1 << 1)
+#define  DPR_SIZE_MASK	0xff0
+#define  DPR_SIZE_SHIFT	4
+#define  DPR_ADDR_MASK	0xfff00000
+#define  DPR_ADDR_SHIFT	20
+
 /* CPU bus clock is fixed at 100MHz */
 #define CPU_BCLK		100
 

src/soc/intel/fsp_broadwell_de/include/soc/ramstage.h

@@ -24,6 +24,8 @@
 void broadwell_de_init_pre_device(void);
 void broadwell_de_init_cpus(struct device *dev);
 void southcluster_enable_dev(struct device *dev);
+void broadwell_de_set_dpr(const uintptr_t addr, const size_t size);
+void broadwell_de_lock_dpr(void);
 
 extern struct pci_operations soc_pci_ops;
 

src/soc/intel/fsp_broadwell_de/ramstage.c

@@ -28,6 +28,7 @@
 #include <soc/pattrs.h>
 #include <soc/pci_devs.h>
 #include <soc/ramstage.h>
+#include <soc/broadwell_de.h>
 
 /* Global PATTRS */
 DEFINE_PATTRS;
@@ -82,3 +83,47 @@ void broadwell_de_init_pre_device(void)
 {
 	fill_in_pattrs();
 }
+
+/*
+ * Set DPR region.
+ */
+void broadwell_de_set_dpr(const uintptr_t addr, const size_t size)
+{
+	struct device *dev;
+	uint32_t dpr_reg;
+	/*
+	 * DMA Protected Range can be reserved below TSEG for PCODE patch
+	 * or TXT/BootGuard related data.  Rather than reporting a base address
+	 * the DPR register reports the TOP of the region, which is the same
+	 * as TSEG base.  The region size is reported in MiB in bits 11:4.
+	 */
+	dev = pcidev_on_root(VTD_DEV, VTD_FUNC);
+	dpr_reg = pci_read_config32(dev, IIO_LTDPR);
+	if (dpr_reg & DPR_LOCK) {
+		printk(BIOS_ERR, "ERROR: HOSTBRIDGE[DPR] is already locked\n");
+		return;
+	}
+
+	dpr_reg &= ~(DPR_ADDR_MASK | DPR_SIZE_MASK);
+	dpr_reg |= addr & DPR_ADDR_MASK;
+	dpr_reg |= (size >> (20 - DPR_SIZE_SHIFT)) & DPR_SIZE_MASK;
+	dpr_reg |= DPR_EPM;
+	pci_write_config32(dev, IIO_LTDPR, dpr_reg);
+}
+
+/*
+ * Lock DPR register.
+ */
+void broadwell_de_lock_dpr(void)
+{
+	struct device *dev;
+	uint32_t dpr_reg;
+	dev = pcidev_on_root(VTD_DEV, VTD_FUNC);
+	dpr_reg = pci_read_config32(dev, IIO_LTDPR);
+	if (dpr_reg & DPR_LOCK) {
+		printk(BIOS_ERR, "ERROR: HOSTBRIDGE[DPR] is already locked\n");
+		return;
+	}
+	dpr_reg |= DPR_LOCK;
+	pci_write_config32(dev, IIO_LTDPR, dpr_reg);
+}