1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Broadcom STB SoCs Bus Unit Interface controls
4 *
5 * Copyright (C) 2015, Broadcom Corporation
6 */
7
8#define pr_fmt(fmt)	"brcmstb: " KBUILD_MODNAME ": " fmt
9
10#include <linux/kernel.h>
11#include <linux/io.h>
12#include <linux/of_address.h>
13#include <linux/syscore_ops.h>
14#include <linux/soc/brcmstb/brcmstb.h>
15
16#define RACENPREF_MASK			0x3
17#define RACPREFINST_SHIFT		0
18#define RACENINST_SHIFT			2
19#define RACPREFDATA_SHIFT		4
20#define RACENDATA_SHIFT			6
21#define RAC_CPU_SHIFT			8
22#define RACCFG_MASK			0xff
23#define DPREF_LINE_2_SHIFT		24
24#define DPREF_LINE_2_MASK		0xff
25
26/* Bitmask to enable instruction and data prefetching with a 256-bytes stride */
27#define RAC_DATA_INST_EN_MASK		(1 << RACPREFINST_SHIFT | \
28					 RACENPREF_MASK << RACENINST_SHIFT | \
29					 1 << RACPREFDATA_SHIFT | \
30					 RACENPREF_MASK << RACENDATA_SHIFT)
31
32#define  CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK	0x70000000
33#define CPU_CREDIT_REG_MCPx_READ_CRED_MASK	0xf
34#define CPU_CREDIT_REG_MCPx_WRITE_CRED_MASK	0xf
35#define CPU_CREDIT_REG_MCPx_READ_CRED_SHIFT(x)	((x) * 8)
36#define CPU_CREDIT_REG_MCPx_WRITE_CRED_SHIFT(x)	(((x) * 8) + 4)
37
38#define CPU_MCP_FLOW_REG_MCPx_RDBUFF_CRED_SHIFT(x)	((x) * 8)
39#define CPU_MCP_FLOW_REG_MCPx_RDBUFF_CRED_MASK		0xff
40
41#define CPU_WRITEBACK_CTRL_REG_WB_THROTTLE_THRESHOLD_MASK	0xf
42#define CPU_WRITEBACK_CTRL_REG_WB_THROTTLE_TIMEOUT_MASK		0xf
43#define CPU_WRITEBACK_CTRL_REG_WB_THROTTLE_TIMEOUT_SHIFT	4
44#define CPU_WRITEBACK_CTRL_REG_WB_THROTTLE_ENABLE		BIT(8)
45
46static void __iomem *cpubiuctrl_base;
47static bool mcp_wr_pairing_en;
48static const int *cpubiuctrl_regs;
49
50enum cpubiuctrl_regs {
51	CPU_CREDIT_REG = 0,
52	CPU_MCP_FLOW_REG,
53	CPU_WRITEBACK_CTRL_REG,
54	RAC_CONFIG0_REG,
55	RAC_CONFIG1_REG,
56	NUM_CPU_BIUCTRL_REGS,
57};
58
59static inline u32 cbc_readl(int reg)
60{
61	int offset = cpubiuctrl_regs[reg];
62
63	if (offset == -1 ||
64	    (IS_ENABLED(CONFIG_CACHE_B15_RAC) && reg >= RAC_CONFIG0_REG))
65		return (u32)-1;
66
67	return readl_relaxed(cpubiuctrl_base + offset);
68}
69
70static inline void cbc_writel(u32 val, int reg)
71{
72	int offset = cpubiuctrl_regs[reg];
73
74	if (offset == -1 ||
75	    (IS_ENABLED(CONFIG_CACHE_B15_RAC) && reg >= RAC_CONFIG0_REG))
76		return;
77
78	writel(val, cpubiuctrl_base + offset);
79}
80
81static const int b15_cpubiuctrl_regs[] = {
82	[CPU_CREDIT_REG] = 0x184,
83	[CPU_MCP_FLOW_REG] = -1,
84	[CPU_WRITEBACK_CTRL_REG] = -1,
85	[RAC_CONFIG0_REG] = -1,
86	[RAC_CONFIG1_REG] = -1,
87};
88
89/* Odd cases, e.g: 7260A0 */
90static const int b53_cpubiuctrl_no_wb_regs[] = {
91	[CPU_CREDIT_REG] = 0x0b0,
92	[CPU_MCP_FLOW_REG] = 0x0b4,
93	[CPU_WRITEBACK_CTRL_REG] = -1,
94	[RAC_CONFIG0_REG] = 0x78,
95	[RAC_CONFIG1_REG] = 0x7c,
96};
97
98static const int b53_cpubiuctrl_regs[] = {
99	[CPU_CREDIT_REG] = 0x0b0,
100	[CPU_MCP_FLOW_REG] = 0x0b4,
101	[CPU_WRITEBACK_CTRL_REG] = 0x22c,
102	[RAC_CONFIG0_REG] = 0x78,
103	[RAC_CONFIG1_REG] = 0x7c,
104};
105
106static const int a72_cpubiuctrl_regs[] = {
107	[CPU_CREDIT_REG] = 0x18,
108	[CPU_MCP_FLOW_REG] = 0x1c,
109	[CPU_WRITEBACK_CTRL_REG] = 0x20,
110	[RAC_CONFIG0_REG] = 0x08,
111	[RAC_CONFIG1_REG] = 0x0c,
112};
113
114static int __init mcp_write_pairing_set(void)
115{
116	u32 creds = 0;
117
118	if (!cpubiuctrl_base)
119		return -1;
120
121	creds = cbc_readl(CPU_CREDIT_REG);
122	if (mcp_wr_pairing_en) {
123		pr_info("MCP: Enabling write pairing\n");
124		cbc_writel(creds | CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK,
125			   CPU_CREDIT_REG);
126	} else if (creds & CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK) {
127		pr_info("MCP: Disabling write pairing\n");
128		cbc_writel(creds & ~CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK,
129			   CPU_CREDIT_REG);
130	} else {
131		pr_info("MCP: Write pairing already disabled\n");
132	}
133
134	return 0;
135}
136
137static const u32 a72_b53_mach_compat[] = {
138	0x7211,
139	0x7216,
140	0x72164,
141	0x72165,
142	0x7255,
143	0x7260,
144	0x7268,
145	0x7271,
146	0x7278,
147};
148
149/* The read-ahead cache present in the Brahma-B53 CPU is a special piece of
150 * hardware after the integrated L2 cache of the B53 CPU complex whose purpose
151 * is to prefetch instruction and/or data with a line size of either 64 bytes
152 * or 256 bytes. The rationale is that the data-bus of the CPU interface is
153 * optimized for 256-byte transactions, and enabling the read-ahead cache
154 * provides a significant performance boost (typically twice the performance
155 * for a memcpy benchmark application).
156 *
157 * The read-ahead cache is transparent for Virtual Address cache maintenance
158 * operations: IC IVAU, DC IVAC, DC CVAC, DC CVAU and DC CIVAC.  So no special
159 * handling is needed for the DMA API above and beyond what is included in the
160 * arm64 implementation.
161 *
162 * In addition, since the Point of Unification is typically between L1 and L2
163 * for the Brahma-B53 processor no special read-ahead cache handling is needed
164 * for the IC IALLU and IC IALLUIS cache maintenance operations.
165 *
166 * However, it is not possible to specify the cache level (L3) for the cache
167 * maintenance instructions operating by set/way to operate on the read-ahead
168 * cache.  The read-ahead cache will maintain coherency when inner cache lines
169 * are cleaned by set/way, but if it is necessary to invalidate inner cache
170 * lines by set/way to maintain coherency with system masters operating on
171 * shared memory that does not have hardware support for coherency, then it
172 * will also be necessary to explicitly invalidate the read-ahead cache.
173 */
174static void __init a72_b53_rac_enable_all(struct device_node *np)
175{
176	unsigned int cpu;
177	u32 enable = 0, pref_dist, shift;
178
179	if (IS_ENABLED(CONFIG_CACHE_B15_RAC))
180		return;
181
182	if (WARN(num_possible_cpus() > 4, "RAC only supports 4 CPUs\n"))
183		return;
184
185	pref_dist = cbc_readl(RAC_CONFIG1_REG);
186	for_each_possible_cpu(cpu) {
187		shift = cpu * RAC_CPU_SHIFT + RACPREFDATA_SHIFT;
188		enable |= RAC_DATA_INST_EN_MASK << (cpu * RAC_CPU_SHIFT);
189		if (cpubiuctrl_regs == a72_cpubiuctrl_regs) {
190			enable &= ~(RACENPREF_MASK << shift);
191			enable |= 3 << shift;
192			pref_dist |= 1 << (cpu + DPREF_LINE_2_SHIFT);
193		}
194	}
195
196	cbc_writel(enable, RAC_CONFIG0_REG);
197	cbc_writel(pref_dist, RAC_CONFIG1_REG);
198
199	pr_info("%pOF: Broadcom %s read-ahead cache\n",
200		np, cpubiuctrl_regs == a72_cpubiuctrl_regs ?
201		"Cortex-A72" : "Brahma-B53");
202}
203
204static void __init mcp_a72_b53_set(void)
205{
206	unsigned int i;
207	u32 reg;
208
209	reg = brcmstb_get_family_id();
210
211	for (i = 0; i < ARRAY_SIZE(a72_b53_mach_compat); i++) {
212		if (BRCM_ID(reg) == a72_b53_mach_compat[i])
213			break;
214	}
215
216	if (i == ARRAY_SIZE(a72_b53_mach_compat))
217		return;
218
219	/* Set all 3 MCP interfaces to 8 credits */
220	reg = cbc_readl(CPU_CREDIT_REG);
221	for (i = 0; i < 3; i++) {
222		reg &= ~(CPU_CREDIT_REG_MCPx_WRITE_CRED_MASK <<
223			 CPU_CREDIT_REG_MCPx_WRITE_CRED_SHIFT(i));
224		reg &= ~(CPU_CREDIT_REG_MCPx_READ_CRED_MASK <<
225			 CPU_CREDIT_REG_MCPx_READ_CRED_SHIFT(i));
226		reg |= 8 << CPU_CREDIT_REG_MCPx_WRITE_CRED_SHIFT(i);
227		reg |= 8 << CPU_CREDIT_REG_MCPx_READ_CRED_SHIFT(i);
228	}
229	cbc_writel(reg, CPU_CREDIT_REG);
230
231	/* Max out the number of in-flight Jwords reads on the MCP interface */
232	reg = cbc_readl(CPU_MCP_FLOW_REG);
233	for (i = 0; i < 3; i++)
234		reg |= CPU_MCP_FLOW_REG_MCPx_RDBUFF_CRED_MASK <<
235			CPU_MCP_FLOW_REG_MCPx_RDBUFF_CRED_SHIFT(i);
236	cbc_writel(reg, CPU_MCP_FLOW_REG);
237
238	/* Enable writeback throttling, set timeout to 128 cycles, 256 cycles
239	 * threshold
240	 */
241	reg = cbc_readl(CPU_WRITEBACK_CTRL_REG);
242	reg |= CPU_WRITEBACK_CTRL_REG_WB_THROTTLE_ENABLE;
243	reg &= ~CPU_WRITEBACK_CTRL_REG_WB_THROTTLE_THRESHOLD_MASK;
244	reg &= ~(CPU_WRITEBACK_CTRL_REG_WB_THROTTLE_TIMEOUT_MASK <<
245		 CPU_WRITEBACK_CTRL_REG_WB_THROTTLE_TIMEOUT_SHIFT);
246	reg |= 8;
247	reg |= 7 << CPU_WRITEBACK_CTRL_REG_WB_THROTTLE_TIMEOUT_SHIFT;
248	cbc_writel(reg, CPU_WRITEBACK_CTRL_REG);
249}
250
251static int __init setup_hifcpubiuctrl_regs(struct device_node *np)
252{
253	struct device_node *cpu_dn;
254	u32 family_id;
255	int ret = 0;
256
257	cpubiuctrl_base = of_iomap(np, 0);
258	if (!cpubiuctrl_base) {
259		pr_err("failed to remap BIU control base\n");
260		ret = -ENOMEM;
261		goto out;
262	}
263
264	mcp_wr_pairing_en = of_property_read_bool(np, "brcm,write-pairing");
265
266	cpu_dn = of_get_cpu_node(0, NULL);
267	if (!cpu_dn) {
268		pr_err("failed to obtain CPU device node\n");
269		ret = -ENODEV;
270		goto out;
271	}
272
273	if (of_device_is_compatible(cpu_dn, "brcm,brahma-b15"))
274		cpubiuctrl_regs = b15_cpubiuctrl_regs;
275	else if (of_device_is_compatible(cpu_dn, "brcm,brahma-b53"))
276		cpubiuctrl_regs = b53_cpubiuctrl_regs;
277	else if (of_device_is_compatible(cpu_dn, "arm,cortex-a72"))
278		cpubiuctrl_regs = a72_cpubiuctrl_regs;
279	else {
280		pr_err("unsupported CPU\n");
281		ret = -EINVAL;
282	}
283	of_node_put(cpu_dn);
284
285	family_id = brcmstb_get_family_id();
286	if (BRCM_ID(family_id) == 0x7260 && BRCM_REV(family_id) == 0)
287		cpubiuctrl_regs = b53_cpubiuctrl_no_wb_regs;
288out:
289	of_node_put(np);
290	return ret;
291}
292
293#ifdef CONFIG_PM_SLEEP
294static u32 cpubiuctrl_reg_save[NUM_CPU_BIUCTRL_REGS];
295
296static int brcmstb_cpu_credit_reg_suspend(void)
297{
298	unsigned int i;
299
300	if (!cpubiuctrl_base)
301		return 0;
302
303	for (i = 0; i < NUM_CPU_BIUCTRL_REGS; i++)
304		cpubiuctrl_reg_save[i] = cbc_readl(i);
305
306	return 0;
307}
308
309static void brcmstb_cpu_credit_reg_resume(void)
310{
311	unsigned int i;
312
313	if (!cpubiuctrl_base)
314		return;
315
316	for (i = 0; i < NUM_CPU_BIUCTRL_REGS; i++)
317		cbc_writel(cpubiuctrl_reg_save[i], i);
318}
319
320static struct syscore_ops brcmstb_cpu_credit_syscore_ops = {
321	.suspend = brcmstb_cpu_credit_reg_suspend,
322	.resume = brcmstb_cpu_credit_reg_resume,
323};
324#endif
325
326
327static int __init brcmstb_biuctrl_init(void)
328{
329	struct device_node *np;
330	int ret;
331
332	/* We might be running on a multi-platform kernel, don't make this a
333	 * fatal error, just bail out early
334	 */
335	np = of_find_compatible_node(NULL, NULL, "brcm,brcmstb-cpu-biu-ctrl");
336	if (!np)
337		return 0;
338
339	ret = setup_hifcpubiuctrl_regs(np);
340	if (ret)
341		return ret;
342
343	ret = mcp_write_pairing_set();
344	if (ret) {
345		pr_err("MCP: Unable to disable write pairing!\n");
346		return ret;
347	}
348
349	a72_b53_rac_enable_all(np);
350	mcp_a72_b53_set();
351#ifdef CONFIG_PM_SLEEP
352	register_syscore_ops(&brcmstb_cpu_credit_syscore_ops);
353#endif
354	return 0;
355}
356early_initcall(brcmstb_biuctrl_init);
357