[PATCH v3 32/57] x86: apl: Allow reading hostbridge base addresses

Simon Glass
2020-09-06T21:43:40Z

Add a few functions to permit reading of various useful base addresses
provided by the hostbridge.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

(no changes since v1)

Changes in v1:
- Add comments

arch/x86/cpu/apollolake/hostbridge.c | 27 ++++++++++++++++
.../include/asm/arch-apollolake/systemagent.h | 31 +++++++++++++++++++
2 files changed, 58 insertions(+)

diff --git a/arch/x86/cpu/apollolake/hostbridge.c b/arch/x86/cpu/apollolake/hostbridge.c
index cb46ec6c0bb..056f7e57a9a 100644
--- a/arch/x86/cpu/apollolake/hostbridge.c
+++ b/arch/x86/cpu/apollolake/hostbridge.c
@@ -40,7 +40,9 @@ enum {

PCIEXBAR_PCIEXBAREN = 1 << 0,

+ BGSM = 0xb4, /* Base GTT Stolen Memory */
TSEG = 0xb8, /* TSEG base */
+ TOLUD = 0xbc,
};

static int apl_hostbridge_early_init_pinctrl(struct udevice *dev)
@@ -165,6 +167,31 @@ static int apl_hostbridge_probe(struct udevice *dev)
return 0;
}

+static ulong sa_read_reg(struct udevice *dev, int reg)
+{
+ u32 val;
+
+ /* All regions concerned for have 1 MiB alignment */
+ dm_pci_read_config32(dev, BGSM, &val);
+
+ return ALIGN_DOWN(val, 1 << 20);
+}
+
+ulong sa_get_tolud_base(struct udevice *dev)
+{
+ return sa_read_reg(dev, TOLUD);
+}
+
+ulong sa_get_gsm_base(struct udevice *dev)
+{
+ return sa_read_reg(dev, BGSM);
+}
+
+ulong sa_get_tseg_base(struct udevice *dev)
+{
+ return sa_read_reg(dev, TSEG);
+}
+
static const struct udevice_id apl_hostbridge_ids[] = {
{ .compatible = "intel,apl-hostbridge" },
{ }
diff --git a/arch/x86/include/asm/arch-apollolake/systemagent.h b/arch/x86/include/asm/arch-apollolake/systemagent.h
index 9e7bd62751a..788a63d7999 100644
--- a/arch/x86/include/asm/arch-apollolake/systemagent.h
+++ b/arch/x86/include/asm/arch-apollolake/systemagent.h
@@ -35,4 +35,35 @@
*/
void enable_bios_reset_cpl(void);

+/**
+ * sa_get_tolud_base() - Get the TOLUD base address
+ *
+ * This returns the Top Of Low Useable DRAM, marking the top of usable DRAM
+ * below 4GB
+ *
+ * @dev: hostbridge device
+ * @return TOLUD address
+ */
+ulong sa_get_tolud_base(struct udevice *dev);
+
+/**
+ * sa_get_gsm_base() - Get the GSM base address
+ *
+ * This returns the base of GTT Stolen Memory, marking the start of memory used
+ * for Graphics Translation Tables.
+ *
+ * @dev: hostbridge device
+ * @return GSM address
+ */
+ulong sa_get_gsm_base(struct udevice *dev);
+
+/**
+ * sa_get_tseg_base() - Get the TSEG base address
+ *
+ * This returns the top address of DRAM available below 4GB
+ *
+ * @return TSEG base
+ */
+ulong sa_get_tseg_base(struct udevice *dev);
+
#endif
--
2.28.0.526.ge36021eeef-goog