southbridge/amd/agesa/hudson: Add initial support for SMM

This sets up the infrastructure to handle SMIs generated by the Hudson
southbridge. An API for interfacing to mainboard handlers is not
defined at this point. A few functions are defined to allow mainboard
code to enable SMIs from GEVENT pins. These are the only functions which
I expect to be needed anytime in the foreseeable future.

SMIs are always acknowledged and cleared, as not clearing an SMI will
cause us to re-enter the SMI, effectively bricking the machine if a
southbridge-generated SMI without a handler occurs.

Change-Id: Ibceb21ac5423eb134d3eb7d24800280b183f7619
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/5494
Reviewed-by: Aaron Durbin <adurbin@gmail.com>
Tested-by: build bot (Jenkins)

src/southbridge/amd/agesa/hudson/Makefile.inc

@@ -22,6 +22,9 @@ ramstage-$(CONFIG_HAVE_ACPI_RESUME) += resume.c
 romstage-y += imc.c
 ramstage-y += imc.c
 
+smm-$(CONFIG_HAVE_SMI_HANDLER) += smihandler.c
+ramstage-$(CONFIG_HAVE_SMI_HANDLER) += smi.c
+
 # ROMSIG At ROMBASE + 0x20000:
 # +-----------+---------------+----------------+------------+
 # |0x55AA55AA |EC ROM Address |GEC ROM Address |USB3 ROM    |

src/southbridge/amd/agesa/hudson/smi.c

@@ -0,0 +1,60 @@
+/*
+ * Utilities for SMM setup
+ *
+ * Copyright (C) 2014 Alexandru Gagniuc <mr.nuke.me@gmail.com>
+ * Subject to the GNU GPL v2, or (at your option) any later version.
+ */
+
+#include "smi.h"
+
+#include <console/console.h>
+#include <cpu/cpu.h>
+
+void smm_setup_structures(void *gnvs, void *tcg, void *smi1)
+{
+	printk(BIOS_DEBUG, "smm_setup_structures STUB!!!\n");
+}
+
+/** Set the EOS bit and enable SMI generation from southbridge */
+void hudson_enable_smi_generation(void)
+{
+	uint32_t reg = smi_read32(SMI_REG_SMITRIG0);
+	reg &= ~SMITRG0_SMIENB;	/* Enable SMI generation */
+	reg |= SMITRG0_EOS;	/* Set EOS bit */
+	smi_write32(SMI_REG_SMITRIG0, reg);
+}
+
+static void enable_smi(uint8_t smi_num)
+{
+	uint8_t reg32_offset, bit_offset;
+	uint32_t reg32;
+
+	/* SMI sources range from [0:149] */
+	if (smi_num > 149) {
+		printk(BIOS_WARNING, "BUG: Invalid SMI: %u\n", smi_num);
+		return;
+	}
+
+	/* 16 sources per register, 2 bits per source; registers are 4 bytes */
+	reg32_offset = (smi_num / 16) * 4;
+	bit_offset = (smi_num % 16) * 2;
+
+	reg32 = smi_read32(SMI_REG_CONTROL0 + reg32_offset);
+	reg32 &= ~(3 << (bit_offset));
+	reg32 |= (SMI_SRC_MODE_SMI << (bit_offset));
+	smi_write32(SMI_REG_CONTROL0 + reg32_offset, reg32);
+
+}
+
+/** Enable generation of SMIs for given GPE */
+void hudson_enable_gevent_smi(uint8_t gevent)
+{
+	/* GEVENT pins range from [0:23] */
+	if (gevent > 23) {
+		printk(BIOS_WARNING, "BUG: Invalid GEVENT: %u\n", gevent);
+		return;
+	}
+
+	/* SMI0 source is GEVENT0 and so on */
+	enable_smi(gevent);
+}

src/southbridge/amd/agesa/hudson/smi.h

@@ -0,0 +1,57 @@
+/*
+ * Utilities for SMI handlers and SMM setup
+ *
+ * Copyright (C) 2014 Alexandru Gagniuc <mr.nuke.me@gmail.com>
+ * Subject to the GNU GPL v2, or (at your option) any later version.
+ */
+
+#ifndef _SOUTHBRIDGE_AMD_AGESA_HUDSON_SMI_H
+#define _SOUTHBRIDGE_AMD_AGESA_HUDSON_SMI_H
+
+#include <arch/io.h>
+
+/* ACPI_MMIO_BASE + 0x200 -- leave this string here so grep catches it.
+ * This is defined by AGESA, but we dpn't include AGESA headers to avoid
+ * polluting the namesace.
+ */
+#define SMI_BASE 0xfed80200
+
+#define SMI_REG_SMITRIG0	0x98
+#define SMITRG0_EOS		(1 << 28)
+#define SMITRG0_SMIENB		(1 << 31)
+
+#define SMI_REG_CONTROL0	0xa0
+
+enum smi_src_mode {
+	SMI_SRC_MODE_DISABLE = 0,
+	SMI_SRC_MODE_SMI = 1,
+	SMI_SRC_MODE_NMI = 2,
+	SMI_SRC_MODE_IRQ13 = 3,
+};
+
+static inline uint32_t smi_read32(uint8_t offset)
+{
+	return read32(SMI_BASE + offset);
+}
+
+static inline void smi_write32(uint8_t offset, uint32_t value)
+{
+	write32(SMI_BASE + offset, value);
+}
+
+static inline uint16_t smi_read16(uint8_t offset)
+{
+	return read16(SMI_BASE + offset);
+}
+
+static inline void smi_write16(uint8_t offset, uint16_t value)
+{
+	write16(SMI_BASE + offset, value);
+}
+
+#ifndef __SMM__
+void hudson_enable_smi_generation(void);
+void hudson_enable_gevent_smi(uint8_t gevent);
+#endif
+
+#endif /* _SOUTHBRIDGE_AMD_AGESA_HUDSON_SMI_H */

src/southbridge/amd/agesa/hudson/smihandler.c

@@ -0,0 +1,100 @@
+/*
+ * SMI handler for Hudson southbridges
+ *
+ * Copyright (C) 2014 Alexandru Gagniuc <mr.nuke.me@gmail.com>
+ * Subject to the GNU GPL v2, or (at your option) any later version.
+ */
+
+#include "smi.h"
+
+#include <console/console.h>
+#include <cpu/x86/smm.h>
+#include <delay.h>
+
+
+enum smi_source {
+	SMI_SOURCE_SCI = (1 << 0),
+	SMI_SOURCE_GPE = (1 << 1),
+	SMI_SOURCE_0x84 = (1 << 2),
+	SMI_SOURCE_0x88 = (1 << 3),
+	SMI_SOURCE_IRQ_TRAP = (1 << 4),
+	SMI_SOURCE_0x90 = (1 << 5)
+};
+
+int southbridge_io_trap_handler(int smif)
+{
+	return 0;
+}
+
+static void process_smi_sci(void)
+{
+	const uint32_t status = smi_read32(0x10);
+
+	/* Clear events to prevent re-entering SMI if event isn't handled */
+	smi_write32(0x10, status);
+}
+
+static void process_gpe_smi(void)
+{
+	const uint32_t status = smi_read32(0x80);
+
+	/* Clear events to prevent re-entering SMI if event isn't handled */
+	smi_write32(0x80, status);
+}
+
+static void process_smi_0x84(void)
+{
+	const uint32_t status = smi_read32(0x84);
+
+	/* Clear events to prevent re-entering SMI if event isn't handled */
+	smi_write32(0x84, status);
+}
+
+static void process_smi_0x88(void)
+{
+	const uint32_t status = smi_read32(0x88);
+
+	/* Clear events to prevent re-entering SMI if event isn't handled */
+	smi_write32(0x88, status);
+}
+
+static void process_smi_0x8c(void)
+{
+	const uint32_t status = smi_read32(0x8c);
+
+	/* Clear events to prevent re-entering SMI if event isn't handled */
+	smi_write32(0x8c, status);
+}
+
+static void process_smi_0x90(void)
+{
+	const uint32_t status = smi_read32(0x90);
+
+	/* Clear events to prevent re-entering SMI if event isn't handled */
+	smi_write32(0x90, status);
+}
+
+void southbridge_smi_handler(unsigned int node, smm_state_save_area_t *state_save)
+{
+	const uint16_t smi_src = smi_read16(0x94);
+
+	if (smi_src & SMI_SOURCE_SCI)
+		process_smi_sci();
+	if (smi_src & SMI_SOURCE_GPE)
+		process_gpe_smi();
+	if (smi_src & SMI_SOURCE_0x84)
+		process_smi_0x84();
+	if (smi_src & SMI_SOURCE_0x88)
+		process_smi_0x88();
+	if (smi_src & SMI_SOURCE_IRQ_TRAP)
+		process_smi_0x8c();
+	if (smi_src & SMI_SOURCE_0x90)
+		process_smi_0x90();
+}
+
+void southbridge_smi_set_eos(void)
+{
+	uint32_t reg = smi_read32(SMI_REG_SMITRIG0);
+	reg |= SMITRG0_EOS;
+	smi_write32(SMI_REG_SMITRIG0, reg);
+}