1 /* 2 * Copyright (C) 2015-2016 Wills Wang <wills.wang@live.com> 3 * 4 * SPDX-License-Identifier: GPL-2.0+ 5 */ 6 7 #include <common.h> 8 #include <spi.h> 9 #include <dm.h> 10 #include <div64.h> 11 #include <errno.h> 12 #include <asm/io.h> 13 #include <asm/addrspace.h> 14 #include <asm/types.h> 15 #include <dm/pinctrl.h> 16 #include <mach/ar71xx_regs.h> 17 18 /* CLOCK_DIVIDER = 3 (SPI clock = 200 / 8 ~ 25 MHz) */ 19 #define ATH79_SPI_CLK_DIV(x) (((x) >> 1) - 1) 20 #define ATH79_SPI_RRW_DELAY_FACTOR 12000 21 #define ATH79_SPI_MHZ (1000 * 1000) 22 23 struct ath79_spi_priv { 24 void __iomem *regs; 25 u32 rrw_delay; 26 }; 27 28 static void spi_cs_activate(struct udevice *dev) 29 { 30 struct udevice *bus = dev_get_parent(dev); 31 struct ath79_spi_priv *priv = dev_get_priv(bus); 32 33 writel(AR71XX_SPI_FS_GPIO, priv->regs + AR71XX_SPI_REG_FS); 34 writel(AR71XX_SPI_IOC_CS_ALL, priv->regs + AR71XX_SPI_REG_IOC); 35 } 36 37 static void spi_cs_deactivate(struct udevice *dev) 38 { 39 struct udevice *bus = dev_get_parent(dev); 40 struct ath79_spi_priv *priv = dev_get_priv(bus); 41 42 writel(AR71XX_SPI_IOC_CS_ALL, priv->regs + AR71XX_SPI_REG_IOC); 43 writel(0, priv->regs + AR71XX_SPI_REG_FS); 44 } 45 46 static int ath79_spi_claim_bus(struct udevice *dev) 47 { 48 return 0; 49 } 50 51 static int ath79_spi_release_bus(struct udevice *dev) 52 { 53 return 0; 54 } 55 56 static int ath79_spi_xfer(struct udevice *dev, unsigned int bitlen, 57 const void *dout, void *din, unsigned long flags) 58 { 59 struct udevice *bus = dev_get_parent(dev); 60 struct ath79_spi_priv *priv = dev_get_priv(bus); 61 struct dm_spi_slave_platdata *slave = dev_get_parent_platdata(dev); 62 u8 *rx = din; 63 const u8 *tx = dout; 64 u8 curbyte, curbitlen, restbits; 65 u32 bytes = bitlen / 8; 66 u32 out, in; 67 u64 tick; 68 69 if (flags & SPI_XFER_BEGIN) 70 spi_cs_activate(dev); 71 72 restbits = (bitlen % 8); 73 if (restbits) 74 bytes++; 75 76 out = AR71XX_SPI_IOC_CS_ALL & ~(AR71XX_SPI_IOC_CS(slave->cs)); 77 while (bytes > 0) { 78 bytes--; 79 curbyte = 0; 80 if (tx) 81 curbyte = *tx++; 82 83 if (restbits && !bytes) { 84 curbitlen = restbits; 85 curbyte <<= 8 - restbits; 86 } else { 87 curbitlen = 8; 88 } 89 90 for (curbyte <<= (8 - curbitlen); curbitlen; curbitlen--) { 91 if (curbyte & 0x80) 92 out |= AR71XX_SPI_IOC_DO; 93 else 94 out &= ~(AR71XX_SPI_IOC_DO); 95 96 writel(out, priv->regs + AR71XX_SPI_REG_IOC); 97 98 /* delay for low level */ 99 if (priv->rrw_delay) { 100 tick = get_ticks() + priv->rrw_delay; 101 while (get_ticks() < tick) 102 /*NOP*/; 103 } 104 105 writel(out | AR71XX_SPI_IOC_CLK, 106 priv->regs + AR71XX_SPI_REG_IOC); 107 108 /* delay for high level */ 109 if (priv->rrw_delay) { 110 tick = get_ticks() + priv->rrw_delay; 111 while (get_ticks() < tick) 112 /*NOP*/; 113 } 114 115 curbyte <<= 1; 116 } 117 118 if (!bytes) 119 writel(out, priv->regs + AR71XX_SPI_REG_IOC); 120 121 in = readl(priv->regs + AR71XX_SPI_REG_RDS); 122 if (rx) { 123 if (restbits && !bytes) 124 *rx++ = (in << (8 - restbits)); 125 else 126 *rx++ = in; 127 } 128 } 129 130 if (flags & SPI_XFER_END) 131 spi_cs_deactivate(dev); 132 133 return 0; 134 } 135 136 137 static int ath79_spi_set_speed(struct udevice *bus, uint speed) 138 { 139 struct ath79_spi_priv *priv = dev_get_priv(bus); 140 u32 val, div = 0; 141 u64 time; 142 143 if (speed) 144 div = get_bus_freq(0) / speed; 145 146 if (div > 63) 147 div = 63; 148 149 if (div < 5) 150 div = 5; 151 152 /* calculate delay */ 153 time = get_tbclk(); 154 do_div(time, speed / 2); 155 val = get_bus_freq(0) / ATH79_SPI_MHZ; 156 val = ATH79_SPI_RRW_DELAY_FACTOR / val; 157 if (time > val) 158 priv->rrw_delay = time - val + 1; 159 else 160 priv->rrw_delay = 0; 161 162 writel(AR71XX_SPI_FS_GPIO, priv->regs + AR71XX_SPI_REG_FS); 163 clrsetbits_be32(priv->regs + AR71XX_SPI_REG_CTRL, 164 AR71XX_SPI_CTRL_DIV_MASK, 165 ATH79_SPI_CLK_DIV(div)); 166 writel(0, priv->regs + AR71XX_SPI_REG_FS); 167 return 0; 168 } 169 170 static int ath79_spi_set_mode(struct udevice *bus, uint mode) 171 { 172 return 0; 173 } 174 175 static int ath79_spi_probe(struct udevice *bus) 176 { 177 struct ath79_spi_priv *priv = dev_get_priv(bus); 178 fdt_addr_t addr; 179 180 addr = devfdt_get_addr(bus); 181 if (addr == FDT_ADDR_T_NONE) 182 return -EINVAL; 183 184 priv->regs = map_physmem(addr, 185 AR71XX_SPI_SIZE, 186 MAP_NOCACHE); 187 188 /* Init SPI Hardware, disable remap, set clock */ 189 writel(AR71XX_SPI_FS_GPIO, priv->regs + AR71XX_SPI_REG_FS); 190 writel(AR71XX_SPI_CTRL_RD | ATH79_SPI_CLK_DIV(8), 191 priv->regs + AR71XX_SPI_REG_CTRL); 192 writel(0, priv->regs + AR71XX_SPI_REG_FS); 193 194 return 0; 195 } 196 197 static int ath79_cs_info(struct udevice *bus, uint cs, 198 struct spi_cs_info *info) 199 { 200 /* Always allow activity on CS 0/1/2 */ 201 if (cs >= 3) 202 return -ENODEV; 203 204 return 0; 205 } 206 207 static const struct dm_spi_ops ath79_spi_ops = { 208 .claim_bus = ath79_spi_claim_bus, 209 .release_bus = ath79_spi_release_bus, 210 .xfer = ath79_spi_xfer, 211 .set_speed = ath79_spi_set_speed, 212 .set_mode = ath79_spi_set_mode, 213 .cs_info = ath79_cs_info, 214 }; 215 216 static const struct udevice_id ath79_spi_ids[] = { 217 { .compatible = "qca,ar7100-spi" }, 218 {} 219 }; 220 221 U_BOOT_DRIVER(ath79_spi) = { 222 .name = "ath79_spi", 223 .id = UCLASS_SPI, 224 .of_match = ath79_spi_ids, 225 .ops = &ath79_spi_ops, 226 .priv_auto_alloc_size = sizeof(struct ath79_spi_priv), 227 .probe = ath79_spi_probe, 228 }; 229