memory: ti-emif-sram: introduce relocatable suspend/resume handlers

Certain SoCs like Texas Instruments AM335x and AM437x require parts
of the EMIF PM code to run late in the suspend sequence from SRAM,
such as saving and restoring the EMIF context and placing the memory
into self-refresh.

One requirement for these SoCs to suspend and enter its lowest power
mode, called DeepSleep0, is that the PER power domain must be shut off.
Because the EMIF (DDR Controller) resides within this power domain, it
will lose context during a suspend operation, so we must save it so we
can restore once we resume. However, we cannot execute this code from
external memory, as it is not available at this point, so the code must
be executed late in the suspend path from SRAM.

This patch introduces a ti-emif-sram driver that includes several
functions written in ARM ASM that are relocatable so the PM SRAM
code can use them. It also allocates a region of writable SRAM to
be used by the code running in the executable region of SRAM to save
and restore the EMIF context. It can export a table containing the
absolute addresses of the available PM functions so that other SRAM
code can branch to them. This code is required for suspend/resume on
AM335x and AM437x to work.

In addition to this, to be able to share data structures between C and
the ti-emif-sram-pm assembly code, we can automatically generate all of
the C struct member offsets and sizes as macros by processing
emif-asm-offsets.c into assembly code and then extracting the relevant
data as is done for the generated platform asm-offsets.h files.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/include/linux/ti-emif-sram.h b/include/linux/ti-emif-sram.h
new file mode 100644
index 000000000000..45bc6b376492
--- /dev/null
+++ b/include/linux/ti-emif-sram.h
@@ -0,0 +1,69 @@
+/*
+ * TI AM33XX EMIF Routines
+ *
+ * Copyright (C) 2016-2017 Texas Instruments Inc.
+ *	Dave Gerlach
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#ifndef __LINUX_TI_EMIF_H
+#define __LINUX_TI_EMIF_H
+
+#include <linux/kbuild.h>
+#include <linux/types.h>
+#ifndef __ASSEMBLY__
+
+struct emif_regs_amx3 {
+	u32 emif_sdcfg_val;
+	u32 emif_timing1_val;
+	u32 emif_timing2_val;
+	u32 emif_timing3_val;
+	u32 emif_ref_ctrl_val;
+	u32 emif_zqcfg_val;
+	u32 emif_pmcr_val;
+	u32 emif_pmcr_shdw_val;
+	u32 emif_rd_wr_level_ramp_ctrl;
+	u32 emif_rd_wr_exec_thresh;
+	u32 emif_cos_config;
+	u32 emif_priority_to_cos_mapping;
+	u32 emif_connect_id_serv_1_map;
+	u32 emif_connect_id_serv_2_map;
+	u32 emif_ocp_config_val;
+	u32 emif_lpddr2_nvm_tim;
+	u32 emif_lpddr2_nvm_tim_shdw;
+	u32 emif_dll_calib_ctrl_val;
+	u32 emif_dll_calib_ctrl_val_shdw;
+	u32 emif_ddr_phy_ctlr_1;
+	u32 emif_ext_phy_ctrl_vals[120];
+};
+
+struct ti_emif_pm_data {
+	void __iomem *ti_emif_base_addr_virt;
+	phys_addr_t ti_emif_base_addr_phys;
+	unsigned long ti_emif_sram_config;
+	struct emif_regs_amx3 *regs_virt;
+	phys_addr_t regs_phys;
+} __packed __aligned(8);
+
+struct ti_emif_pm_functions {
+	u32 save_context;
+	u32 restore_context;
+	u32 enter_sr;
+	u32 exit_sr;
+	u32 abort_sr;
+} __packed __aligned(8);
+
+struct gen_pool;
+
+int ti_emif_copy_pm_function_table(struct gen_pool *sram_pool, void *dst);
+int ti_emif_get_mem_type(void);
+
+#endif
+#endif /* __LINUX_TI_EMIF_H */