1 // SPDX-License-Identifier: GPL-2.0-only 2 // 3 // Copyright (C) 2020 BAIKAL ELECTRONICS, JSC 4 // 5 // Authors: 6 // Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru> 7 // Serge Semin <Sergey.Semin@baikalelectronics.ru> 8 // 9 // Baikal-T1 DW APB SPI and System Boot SPI driver 10 // 11 12 #include <linux/clk.h> 13 #include <linux/cpumask.h> 14 #include <linux/err.h> 15 #include <linux/interrupt.h> 16 #include <linux/module.h> 17 #include <linux/mux/consumer.h> 18 #include <linux/of.h> 19 #include <linux/of_platform.h> 20 #include <linux/platform_device.h> 21 #include <linux/pm_runtime.h> 22 #include <linux/property.h> 23 #include <linux/slab.h> 24 #include <linux/spi/spi-mem.h> 25 #include <linux/spi/spi.h> 26 27 #include "spi-dw.h" 28 29 #define BT1_BOOT_DIRMAP 0 30 #define BT1_BOOT_REGS 1 31 32 struct dw_spi_bt1 { 33 struct dw_spi dws; 34 struct clk *clk; 35 struct mux_control *mux; 36 37 #ifdef CONFIG_SPI_DW_BT1_DIRMAP 38 void __iomem *map; 39 resource_size_t map_len; 40 #endif 41 }; 42 #define to_dw_spi_bt1(_ctlr) \ 43 container_of(spi_controller_get_devdata(_ctlr), struct dw_spi_bt1, dws) 44 45 typedef int (*dw_spi_bt1_init_cb)(struct platform_device *pdev, 46 struct dw_spi_bt1 *dwsbt1); 47 48 #ifdef CONFIG_SPI_DW_BT1_DIRMAP 49 50 static int dw_spi_bt1_dirmap_create(struct spi_mem_dirmap_desc *desc) 51 { 52 struct dw_spi_bt1 *dwsbt1 = to_dw_spi_bt1(desc->mem->spi->controller); 53 54 if (!dwsbt1->map || 55 !dwsbt1->dws.mem_ops.supports_op(desc->mem, &desc->info.op_tmpl)) 56 return -EOPNOTSUPP; 57 58 /* 59 * Make sure the requested region doesn't go out of the physically 60 * mapped flash memory bounds and the operation is read-only. 61 */ 62 if (desc->info.offset + desc->info.length > dwsbt1->map_len || 63 desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN) 64 return -EOPNOTSUPP; 65 66 return 0; 67 } 68 69 /* 70 * Directly mapped SPI memory region is only accessible in the dword chunks. 71 * That's why we have to create a dedicated read-method to copy data from there 72 * to the passed buffer. 73 */ 74 static void dw_spi_bt1_dirmap_copy_from_map(void *to, void __iomem *from, size_t len) 75 { 76 size_t shift, chunk; 77 u32 data; 78 79 /* 80 * We split the copying up into the next three stages: unaligned head, 81 * aligned body, unaligned tail. 82 */ 83 shift = (size_t)from & 0x3; 84 if (shift) { 85 chunk = min_t(size_t, 4 - shift, len); 86 data = readl_relaxed(from - shift); 87 memcpy(to, (char *)&data + shift, chunk); 88 from += chunk; 89 to += chunk; 90 len -= chunk; 91 } 92 93 while (len >= 4) { 94 data = readl_relaxed(from); 95 memcpy(to, &data, 4); 96 from += 4; 97 to += 4; 98 len -= 4; 99 } 100 101 if (len) { 102 data = readl_relaxed(from); 103 memcpy(to, &data, len); 104 } 105 } 106 107 static ssize_t dw_spi_bt1_dirmap_read(struct spi_mem_dirmap_desc *desc, 108 u64 offs, size_t len, void *buf) 109 { 110 struct dw_spi_bt1 *dwsbt1 = to_dw_spi_bt1(desc->mem->spi->controller); 111 struct dw_spi *dws = &dwsbt1->dws; 112 struct spi_mem *mem = desc->mem; 113 struct dw_spi_cfg cfg; 114 int ret; 115 116 /* 117 * Make sure the requested operation length is valid. Truncate the 118 * length if it's greater than the length of the MMIO region. 119 */ 120 if (offs >= dwsbt1->map_len || !len) 121 return 0; 122 123 len = min_t(size_t, len, dwsbt1->map_len - offs); 124 125 /* Collect the controller configuration required by the operation */ 126 cfg.tmode = SPI_TMOD_EPROMREAD; 127 cfg.dfs = 8; 128 cfg.ndf = 4; 129 cfg.freq = mem->spi->max_speed_hz; 130 131 /* Make sure the corresponding CS is de-asserted on transmission */ 132 dw_spi_set_cs(mem->spi, false); 133 134 spi_enable_chip(dws, 0); 135 136 dw_spi_update_config(dws, mem->spi, &cfg); 137 138 spi_umask_intr(dws, SPI_INT_RXFI); 139 140 spi_enable_chip(dws, 1); 141 142 /* 143 * Enable the transparent mode of the System Boot Controller. 144 * The SPI core IO should have been locked before calling this method 145 * so noone would be touching the controller' registers during the 146 * dirmap operation. 147 */ 148 ret = mux_control_select(dwsbt1->mux, BT1_BOOT_DIRMAP); 149 if (ret) 150 return ret; 151 152 dw_spi_bt1_dirmap_copy_from_map(buf, dwsbt1->map + offs, len); 153 154 mux_control_deselect(dwsbt1->mux); 155 156 dw_spi_set_cs(mem->spi, true); 157 158 ret = dw_spi_check_status(dws, true); 159 160 return ret ?: len; 161 } 162 163 #endif /* CONFIG_SPI_DW_BT1_DIRMAP */ 164 165 static int dw_spi_bt1_std_init(struct platform_device *pdev, 166 struct dw_spi_bt1 *dwsbt1) 167 { 168 struct dw_spi *dws = &dwsbt1->dws; 169 170 dws->irq = platform_get_irq(pdev, 0); 171 if (dws->irq < 0) 172 return dws->irq; 173 174 dws->num_cs = 4; 175 176 /* 177 * Baikal-T1 Normal SPI Controllers don't always keep up with full SPI 178 * bus speed especially when it comes to the concurrent access to the 179 * APB bus resources. Thus we have no choice but to set a constraint on 180 * the SPI bus frequency for the memory operations which require to 181 * read/write data as fast as possible. 182 */ 183 dws->max_mem_freq = 20000000U; 184 185 dw_spi_dma_setup_generic(dws); 186 187 return 0; 188 } 189 190 static int dw_spi_bt1_sys_init(struct platform_device *pdev, 191 struct dw_spi_bt1 *dwsbt1) 192 { 193 struct resource *mem __maybe_unused; 194 struct dw_spi *dws = &dwsbt1->dws; 195 196 /* 197 * Baikal-T1 System Boot Controller is equipped with a mux, which 198 * switches between the directly mapped SPI flash access mode and 199 * IO access to the DW APB SSI registers. Note the mux controller 200 * must be setup to preserve the registers being accessible by default 201 * (on idle-state). 202 */ 203 dwsbt1->mux = devm_mux_control_get(&pdev->dev, NULL); 204 if (IS_ERR(dwsbt1->mux)) 205 return PTR_ERR(dwsbt1->mux); 206 207 /* 208 * Directly mapped SPI flash memory is a 16MB MMIO region, which can be 209 * used to access a peripheral memory device just by reading/writing 210 * data from/to it. Note the system APB bus will stall during each IO 211 * from/to the dirmap region until the operation is finished. So don't 212 * use it concurrently with time-critical tasks (like the SPI memory 213 * operations implemented in the DW APB SSI driver). 214 */ 215 #ifdef CONFIG_SPI_DW_BT1_DIRMAP 216 mem = platform_get_resource(pdev, IORESOURCE_MEM, 1); 217 if (mem) { 218 dwsbt1->map = devm_ioremap_resource(&pdev->dev, mem); 219 if (!IS_ERR(dwsbt1->map)) { 220 dwsbt1->map_len = resource_size(mem); 221 dws->mem_ops.dirmap_create = dw_spi_bt1_dirmap_create; 222 dws->mem_ops.dirmap_read = dw_spi_bt1_dirmap_read; 223 } else { 224 dwsbt1->map = NULL; 225 } 226 } 227 #endif /* CONFIG_SPI_DW_BT1_DIRMAP */ 228 229 /* 230 * There is no IRQ, no DMA and just one CS available on the System Boot 231 * SPI controller. 232 */ 233 dws->irq = IRQ_NOTCONNECTED; 234 dws->num_cs = 1; 235 236 /* 237 * Baikal-T1 System Boot SPI Controller doesn't keep up with the full 238 * SPI bus speed due to relatively slow APB bus and races for it' 239 * resources from different CPUs. The situation is worsen by a small 240 * FIFOs depth (just 8 words). It works better in a single CPU mode 241 * though, but still tends to be not fast enough at low CPU 242 * frequencies. 243 */ 244 if (num_possible_cpus() > 1) 245 dws->max_mem_freq = 10000000U; 246 else 247 dws->max_mem_freq = 20000000U; 248 249 return 0; 250 } 251 252 static int dw_spi_bt1_probe(struct platform_device *pdev) 253 { 254 dw_spi_bt1_init_cb init_func; 255 struct dw_spi_bt1 *dwsbt1; 256 struct resource *mem; 257 struct dw_spi *dws; 258 int ret; 259 260 dwsbt1 = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_bt1), GFP_KERNEL); 261 if (!dwsbt1) 262 return -ENOMEM; 263 264 dws = &dwsbt1->dws; 265 266 dws->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &mem); 267 if (IS_ERR(dws->regs)) 268 return PTR_ERR(dws->regs); 269 270 dws->paddr = mem->start; 271 272 dwsbt1->clk = devm_clk_get(&pdev->dev, NULL); 273 if (IS_ERR(dwsbt1->clk)) 274 return PTR_ERR(dwsbt1->clk); 275 276 ret = clk_prepare_enable(dwsbt1->clk); 277 if (ret) 278 return ret; 279 280 dws->bus_num = pdev->id; 281 dws->reg_io_width = 4; 282 dws->max_freq = clk_get_rate(dwsbt1->clk); 283 if (!dws->max_freq) { 284 ret = -EINVAL; 285 goto err_disable_clk; 286 } 287 288 init_func = device_get_match_data(&pdev->dev); 289 ret = init_func(pdev, dwsbt1); 290 if (ret) 291 goto err_disable_clk; 292 293 pm_runtime_enable(&pdev->dev); 294 295 ret = dw_spi_add_host(&pdev->dev, dws); 296 if (ret) 297 goto err_disable_clk; 298 299 platform_set_drvdata(pdev, dwsbt1); 300 301 return 0; 302 303 err_disable_clk: 304 clk_disable_unprepare(dwsbt1->clk); 305 306 return ret; 307 } 308 309 static int dw_spi_bt1_remove(struct platform_device *pdev) 310 { 311 struct dw_spi_bt1 *dwsbt1 = platform_get_drvdata(pdev); 312 313 dw_spi_remove_host(&dwsbt1->dws); 314 315 pm_runtime_disable(&pdev->dev); 316 317 clk_disable_unprepare(dwsbt1->clk); 318 319 return 0; 320 } 321 322 static const struct of_device_id dw_spi_bt1_of_match[] = { 323 { .compatible = "baikal,bt1-ssi", .data = dw_spi_bt1_std_init}, 324 { .compatible = "baikal,bt1-sys-ssi", .data = dw_spi_bt1_sys_init}, 325 { } 326 }; 327 MODULE_DEVICE_TABLE(of, dw_spi_bt1_of_match); 328 329 static struct platform_driver dw_spi_bt1_driver = { 330 .probe = dw_spi_bt1_probe, 331 .remove = dw_spi_bt1_remove, 332 .driver = { 333 .name = "bt1-sys-ssi", 334 .of_match_table = dw_spi_bt1_of_match, 335 }, 336 }; 337 module_platform_driver(dw_spi_bt1_driver); 338 339 MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>"); 340 MODULE_DESCRIPTION("Baikal-T1 System Boot SPI Controller driver"); 341 MODULE_LICENSE("GPL v2"); 342