xref: /openbmc/linux/arch/arm/mach-omap2/sram242x.S (revision 1a59d1b8) 
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * linux/arch/arm/mach-omap2/sram242x.S
4 *
5 * Omap2 specific functions that need to be run in internal SRAM
6 *
7 * (C) Copyright 2004
8 * Texas Instruments, <www.ti.com>
9 * Richard Woodruff <r-woodruff2@ti.com>
10 *
11 * Richard Woodruff notes that any changes to this code must be carefully
12 * audited and tested to ensure that they don't cause a TLB miss while
13 * the SDRAM is inaccessible.  Such a situation will crash the system
14 * since it will cause the ARM MMU to attempt to walk the page tables.
15 * These crashes may be intermittent.
16 */
17#include <linux/linkage.h>
18
19#include <asm/assembler.h>
20
21#include "soc.h"
22#include "iomap.h"
23#include "prm2xxx.h"
24#include "cm2xxx.h"
25#include "sdrc.h"
26
27	.text
28
29	.align	3
30ENTRY(omap242x_sram_ddr_init)
31	stmfd	sp!, {r0 - r12, lr}	@ save registers on stack
32
33	mov	r12, r2			@ capture CS1 vs CS0
34	mov	r8, r3			@ capture force parameter
35
36	/* frequency shift down */
37	ldr	r2, omap242x_sdi_cm_clksel2_pll	@ get address of dpllout reg
38	mov	r3, #0x1		@ value for 1x operation
39	str	r3, [r2]		@ go to L1-freq operation
40
41	/* voltage shift down */
42	mov r9, #0x1			@ set up for L1 voltage call
43	bl voltage_shift		@ go drop voltage
44
45	/* dll lock mode */
46	ldr	r11, omap242x_sdi_sdrc_dlla_ctrl	@ addr of dlla ctrl
47	ldr	r10, [r11]		@ get current val
48	cmp	r12, #0x1		@ cs1 base (2422 es2.05/1)
49	addeq	r11, r11, #0x8		@ if cs1 base, move to DLLB
50	mvn	r9, #0x4		@ mask to get clear bit2
51	and	r10, r10, r9		@ clear bit2 for lock mode.
52	orr	r10, r10, #0x8		@ make sure DLL on (es2 bit pos)
53	orr	r10, r10, #0x2		@ 90 degree phase for all below 133MHz
54	str	r10, [r11]		@ commit to DLLA_CTRL
55	bl	i_dll_wait		@ wait for dll to lock
56
57	/* get dll value */
58	add	r11, r11, #0x4		@ get addr of status reg
59	ldr	r10, [r11]		@ get locked value
60
61	/* voltage shift up */
62	mov r9, #0x0			@ shift back to L0-voltage
63	bl voltage_shift		@ go raise voltage
64
65	/* frequency shift up */
66	mov	r3, #0x2		@ value for 2x operation
67	str	r3, [r2]		@ go to L0-freq operation
68
69	/* reset entry mode for dllctrl */
70	sub	r11, r11, #0x4		@ move from status to ctrl
71	cmp	r12, #0x1		@ normalize if cs1 based
72	subeq	r11, r11, #0x8		@ possibly back to DLLA
73	cmp	r8, #0x1		@ if forced unlock exit
74	orreq	r1, r1, #0x4		@ make sure exit with unlocked value
75	str	r1, [r11]		@ restore DLLA_CTRL high value
76	add	r11, r11, #0x8		@ move to DLLB_CTRL addr
77	str	r1, [r11]		@ set value DLLB_CTRL
78	bl	i_dll_wait		@ wait for possible lock
79
80	/* set up for return, DDR should be good */
81	str r10, [r0]			@ write dll_status and return counter
82	ldmfd	sp!, {r0 - r12, pc}	@ restore regs and return
83
84	/* ensure the DLL has relocked */
85i_dll_wait:
86	mov	r4, #0x800		@ delay DLL relock, min 0x400 L3 clocks
87i_dll_delay:
88	subs	r4, r4, #0x1
89	bne	i_dll_delay
90	ret	lr
91
92	/*
93	 * shift up or down voltage, use R9 as input to tell level.
94	 * wait for it to finish, use 32k sync counter, 1tick=31uS.
95	 */
96voltage_shift:
97	ldr	r4, omap242x_sdi_prcm_voltctrl	@ get addr of volt ctrl.
98	ldr	r5, [r4]		@ get value.
99	ldr	r6, prcm_mask_val	@ get value of mask
100	and	r5, r5, r6		@ apply mask to clear bits
101	orr	r5, r5, r9		@ bulld value for L0/L1-volt operation.
102	str	r5, [r4]		@ set up for change.
103	mov	r3, #0x4000		@ get val for force
104	orr	r5, r5, r3		@ build value for force
105	str	r5, [r4]		@ Force transition to L1
106
107	ldr	r3, omap242x_sdi_timer_32ksynct_cr	@ get addr of counter
108	ldr	r5, [r3]		@ get value
109	add	r5, r5, #0x3		@ give it at most 93uS
110volt_delay:
111	ldr	r7, [r3]		@ get timer value
112	cmp	r5, r7			@ time up?
113	bhi	volt_delay		@ not yet->branch
114	ret	lr			@ back to caller.
115
116omap242x_sdi_cm_clksel2_pll:
117	.word OMAP2420_CM_REGADDR(PLL_MOD, CM_CLKSEL2)
118omap242x_sdi_sdrc_dlla_ctrl:
119	.word OMAP242X_SDRC_REGADDR(SDRC_DLLA_CTRL)
120omap242x_sdi_prcm_voltctrl:
121	.word OMAP2420_PRCM_VOLTCTRL
122prcm_mask_val:
123	.word 0xFFFF3FFC
124omap242x_sdi_timer_32ksynct_cr:
125	.word OMAP2_L4_IO_ADDRESS(OMAP2420_32KSYNCT_BASE + 0x010)
126ENTRY(omap242x_sram_ddr_init_sz)
127	.word	. - omap242x_sram_ddr_init
128
129/*
130 * Reprograms memory timings.
131 * r0 = [PRCM_FULL | PRCM_HALF] r1 = SDRC_DLLA_CTRL value r2 = [DDR | SDR]
132 * PRCM_FULL = 2, PRCM_HALF = 1, DDR = 1, SDR = 0
133 */
134	.align	3
135ENTRY(omap242x_sram_reprogram_sdrc)
136	stmfd	sp!, {r0 - r10, lr}	@ save registers on stack
137	mov	r3, #0x0		@ clear for mrc call
138	mcr	p15, 0, r3, c7, c10, 4	@ memory barrier, finish ARM SDR/DDR
139	nop
140	nop
141	ldr	r6, omap242x_srs_sdrc_rfr_ctrl	@ get addr of refresh reg
142	ldr	r5, [r6]		@ get value
143	mov	r5, r5, lsr #8		@ isolate rfr field and drop burst
144
145	cmp	r0, #0x1		@ going to half speed?
146	movne	r9, #0x0		@ if up set flag up for pre up, hi volt
147
148	blne	voltage_shift_c		@ adjust voltage
149
150	cmp	r0, #0x1		@ going to half speed (post branch link)
151	moveq	r5, r5, lsr #1		@ divide by 2 if to half
152	movne	r5, r5, lsl #1		@ mult by 2 if to full
153	mov	r5, r5, lsl #8		@ put rfr field back into place
154	add	r5, r5, #0x1		@ turn on burst of 1
155	ldr	r4, omap242x_srs_cm_clksel2_pll	@ get address of out reg
156	ldr	r3, [r4]		@ get curr value
157	orr	r3, r3, #0x3
158	bic	r3, r3, #0x3		@ clear lower bits
159	orr	r3, r3, r0		@ new state value
160	str	r3, [r4]		@ set new state (pll/x, x=1 or 2)
161	nop
162	nop
163
164	moveq	r9, #0x1		@ if speed down, post down, drop volt
165	bleq	voltage_shift_c
166
167	mcr	p15, 0, r3, c7, c10, 4	@ memory barrier
168	str	r5, [r6]		@ set new RFR_1 value
169	add	r6, r6, #0x30		@ get RFR_2 addr
170	str	r5, [r6]		@ set RFR_2
171	nop
172	cmp	r2, #0x1		@ (SDR or DDR) do we need to adjust DLL
173	bne	freq_out		@ leave if SDR, no DLL function
174
175	/* With DDR, we need to take care of the DLL for the frequency change */
176	ldr	r2, omap242x_srs_sdrc_dlla_ctrl	@ addr of dlla ctrl
177	str	r1, [r2]		@ write out new SDRC_DLLA_CTRL
178	add	r2, r2, #0x8		@ addr to SDRC_DLLB_CTRL
179	str	r1, [r2]		@ commit to SDRC_DLLB_CTRL
180	mov	r1, #0x2000		@ wait DLL relock, min 0x400 L3 clocks
181dll_wait:
182	subs	r1, r1, #0x1
183	bne	dll_wait
184freq_out:
185	ldmfd	sp!, {r0 - r10, pc}	@ restore regs and return
186
187    /*
188     * shift up or down voltage, use R9 as input to tell level.
189     *	wait for it to finish, use 32k sync counter, 1tick=31uS.
190     */
191voltage_shift_c:
192	ldr	r10, omap242x_srs_prcm_voltctrl	@ get addr of volt ctrl
193	ldr	r8, [r10]		@ get value
194	ldr	r7, ddr_prcm_mask_val	@ get value of mask
195	and	r8, r8, r7		@ apply mask to clear bits
196	orr	r8, r8, r9		@ bulld value for L0/L1-volt operation.
197	str	r8, [r10]		@ set up for change.
198	mov	r7, #0x4000		@ get val for force
199	orr	r8, r8, r7		@ build value for force
200	str	r8, [r10]		@ Force transition to L1
201
202	ldr	r10, omap242x_srs_timer_32ksynct	@ get addr of counter
203	ldr	r8, [r10]		@ get value
204	add	r8, r8, #0x2		@ give it at most 62uS (min 31+)
205volt_delay_c:
206	ldr	r7, [r10]		@ get timer value
207	cmp	r8, r7			@ time up?
208	bhi	volt_delay_c		@ not yet->branch
209	ret	lr			@ back to caller
210
211omap242x_srs_cm_clksel2_pll:
212	.word OMAP2420_CM_REGADDR(PLL_MOD, CM_CLKSEL2)
213omap242x_srs_sdrc_dlla_ctrl:
214	.word OMAP242X_SDRC_REGADDR(SDRC_DLLA_CTRL)
215omap242x_srs_sdrc_rfr_ctrl:
216	.word OMAP242X_SDRC_REGADDR(SDRC_RFR_CTRL_0)
217omap242x_srs_prcm_voltctrl:
218	.word OMAP2420_PRCM_VOLTCTRL
219ddr_prcm_mask_val:
220	.word 0xFFFF3FFC
221omap242x_srs_timer_32ksynct:
222	.word OMAP2_L4_IO_ADDRESS(OMAP2420_32KSYNCT_BASE + 0x010)
223
224ENTRY(omap242x_sram_reprogram_sdrc_sz)
225	.word	. - omap242x_sram_reprogram_sdrc
226
227/*
228 * Set dividers and pll. Also recalculate DLL value for DDR and unlock mode.
229 */
230	.align	3
231ENTRY(omap242x_sram_set_prcm)
232	stmfd	sp!, {r0-r12, lr}	@ regs to stack
233	adr	r4, pbegin		@ addr of preload start
234	adr	r8, pend		@ addr of preload end
235	mcrr	p15, 1, r8, r4, c12	@ preload into icache
236pbegin:
237	/* move into fast relock bypass */
238	ldr	r8, omap242x_ssp_pll_ctl	@ get addr
239	ldr	r5, [r8]		@ get val
240	mvn	r6, #0x3		@ clear mask
241	and	r5, r5, r6		@ clear field
242	orr	r7, r5, #0x2		@ fast relock val
243	str	r7, [r8]		@ go to fast relock
244	ldr	r4, omap242x_ssp_pll_stat	@ addr of stat
245block:
246	/* wait for bypass */
247	ldr	r8, [r4]		@ stat value
248	and	r8, r8, #0x3		@ mask for stat
249	cmp	r8, #0x1		@ there yet
250	bne	block			@ loop if not
251
252	/* set new dpll dividers _after_ in bypass */
253	ldr	r4, omap242x_ssp_pll_div	@ get addr
254	str	r0, [r4]		@ set dpll ctrl val
255
256	ldr	r4, omap242x_ssp_set_config	@ get addr
257	mov	r8, #1			@ valid cfg msk
258	str	r8, [r4]		@ make dividers take
259
260	mov	r4, #100		@ dead spin a bit
261wait_a_bit:
262	subs	r4, r4, #1		@ dec loop
263	bne	wait_a_bit		@ delay done?
264
265	/* check if staying in bypass */
266	cmp	r2, #0x1		@ stay in bypass?
267	beq	pend			@ jump over dpll relock
268
269	/* relock DPLL with new vals */
270	ldr	r5, omap242x_ssp_pll_stat	@ get addr
271	ldr	r4, omap242x_ssp_pll_ctl	@ get addr
272	orr	r8, r7, #0x3		@ val for lock dpll
273	str	r8, [r4]		@ set val
274	mov	r0, #1000		@ dead spin a bit
275wait_more:
276	subs	r0, r0, #1		@ dec loop
277	bne	wait_more		@ delay done?
278wait_lock:
279	ldr	r8, [r5]		@ get lock val
280	and	r8, r8, #3		@ isolate field
281	cmp	r8, #2			@ locked?
282	bne	wait_lock		@ wait if not
283pend:
284	/* update memory timings & briefly lock dll */
285	ldr	r4, omap242x_ssp_sdrc_rfr	@ get addr
286	str	r1, [r4]		@ update refresh timing
287	ldr	r11, omap242x_ssp_dlla_ctrl	@ get addr of DLLA ctrl
288	ldr	r10, [r11]		@ get current val
289	mvn	r9, #0x4		@ mask to get clear bit2
290	and	r10, r10, r9		@ clear bit2 for lock mode
291	orr	r10, r10, #0x8		@ make sure DLL on (es2 bit pos)
292	str	r10, [r11]		@ commit to DLLA_CTRL
293	add	r11, r11, #0x8		@ move to dllb
294	str	r10, [r11]		@ hit DLLB also
295
296	mov	r4, #0x800		@ relock time (min 0x400 L3 clocks)
297wait_dll_lock:
298	subs	r4, r4, #0x1
299	bne	wait_dll_lock
300	nop
301	ldmfd	sp!, {r0-r12, pc}	@ restore regs and return
302
303omap242x_ssp_set_config:
304	.word OMAP2420_PRCM_CLKCFG_CTRL
305omap242x_ssp_pll_ctl:
306	.word OMAP2420_CM_REGADDR(PLL_MOD, CM_CLKEN)
307omap242x_ssp_pll_stat:
308	.word OMAP2420_CM_REGADDR(PLL_MOD, CM_IDLEST)
309omap242x_ssp_pll_div:
310	.word OMAP2420_CM_REGADDR(PLL_MOD, CM_CLKSEL1)
311omap242x_ssp_sdrc_rfr:
312	.word OMAP242X_SDRC_REGADDR(SDRC_RFR_CTRL_0)
313omap242x_ssp_dlla_ctrl:
314	.word OMAP242X_SDRC_REGADDR(SDRC_DLLA_CTRL)
315
316ENTRY(omap242x_sram_set_prcm_sz)
317	.word	. - omap242x_sram_set_prcm
318