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memory: ti-emif-sram: Add ti_emif_run_hw_leveling for DDR3 hardware leveling

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In certain situations, such as when returning from low power modes, the
EMIF must re-run hardware leveling to properly restore DDR3 access.

This is accomplished by introducing a new ti-emif-sram-pm call,
ti_emif_run_hw_leveling, to check if DDR3 is in use and if so, trigger
the full write and read leveling processes.

Suggested-by: Brad Griffis <bgriffis@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This commit is contained in:
Dave Gerlach 2019-04-02 11:57:42 -05:00 committed by Tony Lindgren
parent 9e98c678c2
commit 6c110561eb
4 changed files with 51 additions and 0 deletions
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4
drivers/memory/emif.h
View file

@ -537,6 +537,9 @@
#define MCONNID_SHIFT 0
#define MCONNID_MASK (0xff << 0)
/* READ_WRITE_LEVELING_CONTROL */
#define RDWRLVLFULL_START 0x80000000
/* DDR_PHY_CTRL_1 - EMIF4D */
#define DLL_SLAVE_DLY_CTRL_SHIFT_4D 4
#define DLL_SLAVE_DLY_CTRL_MASK_4D (0xFF << 4)
@ -598,6 +601,7 @@ extern struct emif_regs_amx3 ti_emif_regs_amx3;
void ti_emif_save_context(void);
void ti_emif_restore_context(void);
void ti_emif_run_hw_leveling(void);
void ti_emif_enter_sr(void);
void ti_emif_exit_sr(void);
void ti_emif_abort_sr(void);

3
drivers/memory/ti-emif-pm.c
View file

@ -138,6 +138,9 @@ static int ti_emif_alloc_sram(struct device *dev,
emif_data->pm_functions.exit_sr =
sram_resume_address(emif_data,
(unsigned long)ti_emif_exit_sr);
emif_data->pm_functions.run_hw_leveling =
sram_resume_address(emif_data,
(unsigned long)ti_emif_run_hw_leveling);
emif_data->pm_data.regs_virt =
(struct emif_regs_amx3 *)emif_data->ti_emif_sram_data_virt;

41
drivers/memory/ti-emif-sram-pm.S
View file

@ -27,6 +27,7 @@
#define EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK 0x0700
#define EMIF_SDCFG_TYPE_DDR2 0x2 << SDRAM_TYPE_SHIFT
#define EMIF_SDCFG_TYPE_DDR3 0x3 << SDRAM_TYPE_SHIFT
#define EMIF_STATUS_READY 0x4
#define AM43XX_EMIF_PHY_CTRL_REG_COUNT 0x120
@ -244,6 +245,46 @@ emif_skip_restore_extra_regs:
mov pc, lr
ENDPROC(ti_emif_restore_context)
/*
* void ti_emif_run_hw_leveling(void)
*
* Used during resume to run hardware leveling again and restore the
* configuration of the EMIF PHY, only for DDR3.
*/
ENTRY(ti_emif_run_hw_leveling)
adr r4, ti_emif_pm_sram_data
ldr r0, [r4, #EMIF_PM_BASE_ADDR_PHYS_OFFSET]
ldr r3, [r0, #EMIF_READ_WRITE_LEVELING_CONTROL]
orr r3, r3, #RDWRLVLFULL_START
ldr r2, [r0, #EMIF_SDRAM_CONFIG]
and r2, r2, #SDRAM_TYPE_MASK
cmp r2, #EMIF_SDCFG_TYPE_DDR3
bne skip_hwlvl
str r3, [r0, #EMIF_READ_WRITE_LEVELING_CONTROL]
/*
* If EMIF registers are touched during initial stage of HW
* leveling sequence there will be an L3 NOC timeout error issued
* as the EMIF will not respond, which is not fatal, but it is
* avoidable. This small wait loop is enough time for this condition
* to clear, even at worst case of CPU running at max speed of 1Ghz.
*/
mov r2, #0x2000
1:
subs r2, r2, #0x1
bne 1b
/* Bit clears when operation is complete */
2: ldr r1, [r0, #EMIF_READ_WRITE_LEVELING_CONTROL]
tst r1, #RDWRLVLFULL_START
bne 2b
skip_hwlvl:
mov pc, lr
ENDPROC(ti_emif_run_hw_leveling)
/*
* void ti_emif_enter_sr(void)
*

3
include/linux/ti-emif-sram.h
View file

@ -55,6 +55,7 @@ struct ti_emif_pm_data {
struct ti_emif_pm_functions {
u32 save_context;
u32 restore_context;
u32 run_hw_leveling;
u32 enter_sr;
u32 exit_sr;
u32 abort_sr;
@ -126,6 +127,8 @@ static inline void ti_emif_asm_offsets(void)
offsetof(struct ti_emif_pm_functions, save_context));
DEFINE(EMIF_PM_RESTORE_CONTEXT_OFFSET,
offsetof(struct ti_emif_pm_functions, restore_context));
DEFINE(EMIF_PM_RUN_HW_LEVELING,
offsetof(struct ti_emif_pm_functions, run_hw_leveling));
DEFINE(EMIF_PM_ENTER_SR_OFFSET,
offsetof(struct ti_emif_pm_functions, enter_sr));
DEFINE(EMIF_PM_EXIT_SR_OFFSET,