/* * Copyright (c) 2012 The Linux Foundation. All rights reserved. */ #include #include #include #include #include #include #include #include #define SUCCESS 0 #define DUMMY_DATA_VAL 0 #define TIMEOUT_CNT 100 #define CS_ASSERT 1 #define CS_DEASSERT 0 #define NUM_PORTS 3 #define NUM_GSBI_PINS 3 #define TLMM_ARGS 6 #define NUM_CS 4 #define GSBI_PIN_IDX 0 #define FUNC_SEL_IDX 1 #define GPIO_DIR_IDX 2 #define PULL_CONF_IDX 3 #define DRV_STR_IDX 4 #define GPIO_EN_IDX 5 /* Arbitrarily assigned error code values */ #define ETIMEDOUT -10 #define EINVAL -11 #define EIO -12 #define GSBI_IDX_TO_GSBI(idx) (idx + 5) /* MX_INPUT_COUNT and MX_OUTPUT_COUNT are 16-bits. Zero has a special meaning * (count function disabled) and does not hold significance in the count. */ #define MAX_PACKET_COUNT ((64 * KiB) - 1) /* * TLMM Configuration for SPI NOR * gsbi_pin_conf[bus_num][GPIO_NUM, FUNC_SEL, I/O, * PULL UP/DOWN, DRV_STR, GPIO_FUNC] * gsbi_pin_conf[0][x][y] -- GSBI5 * gsbi_pin_conf[1][x][y] -- GSBI6 * gsbi_pin_conf[2][x][y] -- GSBI7 */ static unsigned int gsbi_pin_conf[NUM_PORTS][NUM_GSBI_PINS][TLMM_ARGS] = { { /* GSBI5 CLK */ { GSBI5_SPI_CLK, FUNC_SEL_1, GPIO_INPUT, GPIO_PULL_DOWN, GPIO_DRV_STR_11MA, GPIO_FUNC_DISABLE }, /* GSBI5 MISO */ { GSBI5_SPI_MISO, FUNC_SEL_1, GPIO_INPUT, GPIO_PULL_DOWN, GPIO_DRV_STR_10MA, GPIO_FUNC_DISABLE }, /* GSBI5 MOSI */ { GSBI5_SPI_MOSI, FUNC_SEL_1, GPIO_INPUT, GPIO_PULL_DOWN, GPIO_DRV_STR_10MA, GPIO_FUNC_DISABLE } }, { /* GSBI6 CLK */ { GSBI6_SPI_CLK, FUNC_SEL_3, GPIO_INPUT, GPIO_PULL_DOWN, GPIO_DRV_STR_11MA, GPIO_FUNC_DISABLE }, /* GSBI6 MISO */ { GSBI6_SPI_MISO, FUNC_SEL_3, GPIO_INPUT, GPIO_PULL_DOWN, GPIO_DRV_STR_10MA, GPIO_FUNC_DISABLE }, /* GSBI6 MOSI */ { GSBI6_SPI_MOSI, FUNC_SEL_3, GPIO_INPUT, GPIO_PULL_DOWN, GPIO_DRV_STR_10MA, GPIO_FUNC_DISABLE } }, { /* GSBI7 CLK */ { GSBI7_SPI_CLK, FUNC_SEL_1, GPIO_INPUT, GPIO_PULL_DOWN, GPIO_DRV_STR_11MA, GPIO_FUNC_DISABLE }, /* GSBI7 MISO */ { GSBI7_SPI_MISO, FUNC_SEL_1, GPIO_INPUT, GPIO_PULL_DOWN, GPIO_DRV_STR_10MA, GPIO_FUNC_DISABLE }, /* GSBI7 MOSI */ { GSBI7_SPI_MOSI, FUNC_SEL_1, GPIO_INPUT, GPIO_PULL_DOWN, GPIO_DRV_STR_10MA, GPIO_FUNC_DISABLE } } }; /* * CS GPIO number array cs_gpio_array[port_num][cs_num] * cs_gpio_array[0][x] -- GSBI5 * cs_gpio_array[1][x] -- GSBI6 * cs_gpio_array[2][x] -- GSBI7 */ static unsigned int cs_gpio_array[NUM_PORTS][NUM_CS] = { { GSBI5_SPI_CS_0, GSBI5_SPI_CS_1, GSBI5_SPI_CS_2, GSBI5_SPI_CS_3 }, { GSBI6_SPI_CS_0, 0, 0, 0 }, { GSBI7_SPI_CS_0, 0, 0, 0 } }; /* * GSBI HCLK state register bit * hclk_state[0] -- GSBI5 * hclk_state[1] -- GSBI6 * hclk_state[2] -- GSBI7 */ static unsigned int hclk_state[NUM_PORTS] = { GSBI5_HCLK, GSBI6_HCLK, GSBI7_HCLK }; /* * GSBI QUP_APPS_CLK state register bit * qup_apps_clk_state[0] -- GSBI5 * qup_apps_clk_state[1] -- GSBI6 * qup_apps_clk_state[2] -- GSBI7 */ static unsigned int qup_apps_clk_state[NUM_PORTS] = { GSBI5_QUP_APPS_CLK, GSBI6_QUP_APPS_CLK, GSBI7_QUP_APPS_CLK }; static int check_bit_state(uint32_t reg_addr, int bit_num, int val, int us_delay) { unsigned int count = TIMEOUT_CNT; unsigned int bit_val = ((readl_i(reg_addr) >> bit_num) & 0x01); while (bit_val != val) { count--; if (count == 0) return -ETIMEDOUT; udelay(us_delay); bit_val = ((readl_i(reg_addr) >> bit_num) & 0x01); } return SUCCESS; } /* * Check whether GSBIn_QUP State is valid */ static int check_qup_state_valid(struct ipq_spi_slave *ds) { return check_bit_state(ds->regs->qup_state, QUP_STATE_VALID_BIT, QUP_STATE_VALID, 1); } /* * Configure GSBIn Core state */ static int config_spi_state(struct ipq_spi_slave *ds, unsigned int state) { uint32_t val; int ret; uint32_t new_state; ret = check_qup_state_valid(ds); if (ret != SUCCESS) return ret; switch (state) { case SPI_RUN_STATE: new_state = QUP_STATE_RUN_STATE; break; case SPI_RESET_STATE: new_state = QUP_STATE_RESET_STATE; break; case SPI_PAUSE_STATE: new_state = QUP_STATE_PAUSE_STATE; break; default: printk(BIOS_ERR, "err: unsupported GSBI SPI state : %d\n", state); return -EINVAL; } /* Set the state as requested */ val = (readl_i(ds->regs->qup_state) & ~QUP_STATE_MASK) | new_state; writel_i(val, ds->regs->qup_state); return check_qup_state_valid(ds); } /* * Set GSBIn SPI Mode */ static void spi_set_mode(struct ipq_spi_slave *ds, unsigned int mode) { unsigned int clk_idle_state; unsigned int input_first_mode; uint32_t val; switch (mode) { case GSBI_SPI_MODE_0: clk_idle_state = 0; input_first_mode = SPI_INPUT_FIRST_MODE; break; case GSBI_SPI_MODE_1: clk_idle_state = 0; input_first_mode = 0; break; case GSBI_SPI_MODE_2: clk_idle_state = 1; input_first_mode = SPI_INPUT_FIRST_MODE; break; case GSBI_SPI_MODE_3: clk_idle_state = 1; input_first_mode = 0; break; default: printk(BIOS_ERR, "err : unsupported spi mode : %d\n", mode); return; } val = readl_i(ds->regs->spi_config); val |= input_first_mode; writel_i(val, ds->regs->spi_config); val = readl_i(ds->regs->io_control); if (clk_idle_state) val |= SPI_IO_CONTROL_CLOCK_IDLE_HIGH; else val &= ~SPI_IO_CONTROL_CLOCK_IDLE_HIGH; writel_i(val, ds->regs->io_control); } /* * Check for HCLK state */ static int check_hclk_state(unsigned int core_num, int enable) { return check_bit_state(CLK_HALT_CFPB_STATEB_REG, hclk_state[core_num], enable, 5); } /* * Check for QUP APPS CLK state */ static int check_qup_clk_state(unsigned int core_num, int enable) { return check_bit_state(CLK_HALT_CFPB_STATEB_REG, qup_apps_clk_state[core_num], enable, 5); } /* * Function to assert and De-assert chip select */ static void CS_change(int port_num, int cs_num, int enable) { unsigned int cs_gpio = cs_gpio_array[port_num][cs_num]; void *addr = GPIO_IN_OUT_ADDR(cs_gpio); uint32_t val = readl_i(addr); val &= (~(1 << GPIO_OUTPUT)); if (!enable) val |= (1 << GPIO_OUTPUT); write32(addr, val); } /* * GSBIn TLMM configuration */ static void gsbi_pin_config(unsigned int port_num, int cs_num) { unsigned int gpio; unsigned int i; /* Hold the GSBIn (core_num) core in reset */ clrsetbits_le32_i(GSBIn_RESET_REG(GSBI_IDX_TO_GSBI(port_num)), GSBI1_RESET_MSK, GSBI1_RESET); /* * Configure SPI_CLK, SPI_MISO and SPI_MOSI */ for (i = 0; i < NUM_GSBI_PINS; i++) { unsigned int func_sel; unsigned int io_config; unsigned int pull_config; unsigned int drv_strength; unsigned int gpio_en; unsigned int *ptr; ptr = gsbi_pin_conf[port_num][i]; gpio = *(ptr + GSBI_PIN_IDX); func_sel = *(ptr + FUNC_SEL_IDX); io_config = *(ptr + GPIO_DIR_IDX); pull_config = *(ptr + PULL_CONF_IDX); drv_strength = *(ptr + DRV_STR_IDX); gpio_en = *(ptr + GPIO_EN_IDX); gpio_tlmm_config(gpio, func_sel, io_config, pull_config, drv_strength, gpio_en); } gpio = cs_gpio_array[port_num][cs_num]; /* configure CS */ gpio_tlmm_config(gpio, FUNC_SEL_GPIO, GPIO_OUTPUT, GPIO_PULL_UP, GPIO_DRV_STR_10MA, GPIO_FUNC_ENABLE); CS_change(port_num, cs_num, CS_DEASSERT); } /* * Clock configuration for GSBIn Core */ static int gsbi_clock_init(struct ipq_spi_slave *ds) { int ret; /* Hold the GSBIn (core_num) core in reset */ clrsetbits_le32_i(GSBIn_RESET_REG(GSBI_IDX_TO_GSBI(ds->slave.bus)), GSBI1_RESET_MSK, GSBI1_RESET); /* Disable GSBIn (core_num) QUP core clock branch */ clrsetbits_le32_i(ds->regs->qup_ns_reg, QUP_CLK_BRANCH_ENA_MSK, QUP_CLK_BRANCH_DIS); ret = check_qup_clk_state(ds->slave.bus, 1); if (ret) { printk(BIOS_ERR, "QUP Clock Halt For GSBI%d failed!\n", ds->slave.bus); return ret; } /* Disable M/N:D counter and hold M/N:D counter in reset */ clrsetbits_le32_i(ds->regs->qup_ns_reg, (MNCNTR_MSK | MNCNTR_RST_MSK), (MNCNTR_RST_ENA | MNCNTR_DIS)); /* Disable GSBIn (core_num) QUP core clock root */ clrsetbits_le32_i(ds->regs->qup_ns_reg, CLK_ROOT_ENA_MSK, CLK_ROOT_DIS); clrsetbits_le32_i(ds->regs->qup_ns_reg, GSBIn_PLL_SRC_MSK, GSBIn_PLL_SRC_PLL8); clrsetbits_le32_i(ds->regs->qup_ns_reg, GSBIn_PRE_DIV_SEL_MSK, (0 << GSBI_PRE_DIV_SEL_SHFT)); /* Program M/N:D values for GSBIn_QUP_APPS_CLK @50MHz */ clrsetbits_le32_i(ds->regs->qup_md_reg, GSBIn_M_VAL_MSK, (0x01 << GSBI_M_VAL_SHFT)); clrsetbits_le32_i(ds->regs->qup_md_reg, GSBIn_D_VAL_MSK, (0xF7 << GSBI_D_VAL_SHFT)); clrsetbits_le32_i(ds->regs->qup_ns_reg, GSBIn_N_VAL_MSK, (0xF8 << GSBI_N_VAL_SHFT)); /* Set MNCNTR_MODE = 0: Bypass mode */ clrsetbits_le32_i(ds->regs->qup_ns_reg, MNCNTR_MODE_MSK, MNCNTR_MODE_DUAL_EDGE); /* De-assert the M/N:D counter reset */ clrsetbits_le32_i(ds->regs->qup_ns_reg, MNCNTR_RST_MSK, MNCNTR_RST_DIS); clrsetbits_le32_i(ds->regs->qup_ns_reg, MNCNTR_MSK, MNCNTR_EN); /* * Enable the GSBIn (core_num) QUP core clock root. * Keep MND counter disabled */ clrsetbits_le32_i(ds->regs->qup_ns_reg, CLK_ROOT_ENA_MSK, CLK_ROOT_ENA); /* Enable GSBIn (core_num) QUP core clock branch */ clrsetbits_le32_i(ds->regs->qup_ns_reg, QUP_CLK_BRANCH_ENA_MSK, QUP_CLK_BRANCH_ENA); ret = check_qup_clk_state(ds->slave.bus, 0); if (ret) { printk(BIOS_ERR, "QUP Clock Enable For GSBI%d" " failed!\n", ds->slave.bus); return ret; } /* Enable GSBIn (core_num) core clock branch */ clrsetbits_le32_i(GSBIn_HCLK_CTL_REG(GSBI_IDX_TO_GSBI(ds->slave.bus)), GSBI_CLK_BRANCH_ENA_MSK, GSBI_CLK_BRANCH_ENA); ret = check_hclk_state(ds->slave.bus, 0); if (ret) { printk(BIOS_ERR, "HCLK Enable For GSBI%d failed!\n", ds->slave.bus); return ret; } /* Release GSBIn (core_num) core from reset */ clrsetbits_le32_i(GSBIn_RESET_REG(GSBI_IDX_TO_GSBI(ds->slave.bus)), GSBI1_RESET_MSK, 0); udelay(50); return SUCCESS; } /* * Reset entire QUP and all mini cores */ static void spi_reset(struct ipq_spi_slave *ds) { writel_i(0x1, ds->regs->qup_sw_reset); udelay(5); } static const struct gsbi_spi spi_reg[] = { /* GSBI5 registers for SPI interface */ { GSBI5_SPI_CONFIG_REG, GSBI5_SPI_IO_CONTROL_REG, GSBI5_SPI_ERROR_FLAGS_REG, GSBI5_SPI_ERROR_FLAGS_EN_REG, GSBI5_GSBI_CTRL_REG_REG, GSBI5_QUP_CONFIG_REG, GSBI5_QUP_ERROR_FLAGS_REG, GSBI5_QUP_ERROR_FLAGS_EN_REG, GSBI5_QUP_OPERATIONAL_REG, GSBI5_QUP_IO_MODES_REG, GSBI5_QUP_STATE_REG, GSBI5_QUP_INPUT_FIFOc_REG(0), GSBI5_QUP_OUTPUT_FIFOc_REG(0), GSBI5_QUP_MX_INPUT_COUNT_REG, GSBI5_QUP_MX_OUTPUT_COUNT_REG, GSBI5_QUP_SW_RESET_REG, GSBIn_QUP_APPS_NS_REG(5), GSBIn_QUP_APPS_MD_REG(5), }, /* GSBI6 registers for SPI interface */ { GSBI6_SPI_CONFIG_REG, GSBI6_SPI_IO_CONTROL_REG, GSBI6_SPI_ERROR_FLAGS_REG, GSBI6_SPI_ERROR_FLAGS_EN_REG, GSBI6_GSBI_CTRL_REG_REG, GSBI6_QUP_CONFIG_REG, GSBI6_QUP_ERROR_FLAGS_REG, GSBI6_QUP_ERROR_FLAGS_EN_REG, GSBI6_QUP_OPERATIONAL_REG, GSBI6_QUP_IO_MODES_REG, GSBI6_QUP_STATE_REG, GSBI6_QUP_INPUT_FIFOc_REG(0), GSBI6_QUP_OUTPUT_FIFOc_REG(0), GSBI6_QUP_MX_INPUT_COUNT_REG, GSBI6_QUP_MX_OUTPUT_COUNT_REG, GSBI6_QUP_SW_RESET_REG, GSBIn_QUP_APPS_NS_REG(6), GSBIn_QUP_APPS_MD_REG(6), }, /* GSBI7 registers for SPI interface */ { GSBI7_SPI_CONFIG_REG, GSBI7_SPI_IO_CONTROL_REG, GSBI7_SPI_ERROR_FLAGS_REG, GSBI7_SPI_ERROR_FLAGS_EN_REG, GSBI7_GSBI_CTRL_REG_REG, GSBI7_QUP_CONFIG_REG, GSBI7_QUP_ERROR_FLAGS_REG, GSBI7_QUP_ERROR_FLAGS_EN_REG, GSBI7_QUP_OPERATIONAL_REG, GSBI7_QUP_IO_MODES_REG, GSBI7_QUP_STATE_REG, GSBI7_QUP_INPUT_FIFOc_REG(0), GSBI7_QUP_OUTPUT_FIFOc_REG(0), GSBI7_QUP_MX_INPUT_COUNT_REG, GSBI7_QUP_MX_OUTPUT_COUNT_REG, GSBI7_QUP_SW_RESET_REG, GSBIn_QUP_APPS_NS_REG(7), GSBIn_QUP_APPS_MD_REG(7), } }; static struct ipq_spi_slave spi_slave_pool[2]; void spi_init() { /* just in case */ memset(spi_slave_pool, 0, sizeof(spi_slave_pool)); } struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs) { struct ipq_spi_slave *ds = NULL; int i; /* * IPQ GSBI (Generic Serial Bus Interface) supports SPI Flash * on different GSBI5, GSBI6 and GSBI7 * with different number of chip selects (CS, channels): */ if ((bus < GSBI5_SPI) || (bus > GSBI7_SPI) || ((bus == GSBI5_SPI) && (cs > 3)) || ((bus == GSBI6_SPI) && (cs > 0)) || ((bus == GSBI7_SPI) && (cs > 0))) { printk(BIOS_ERR, "SPI error: unsupported bus %d " "(Supported busses 0,1 and 2) or chipselect\n", bus); } for (i = 0; i < ARRAY_SIZE(spi_slave_pool); i++) { if (spi_slave_pool[i].allocated) continue; ds = spi_slave_pool + i; ds->slave.bus = bus; ds->slave.cs = cs; ds->regs = &spi_reg[bus]; /* * TODO(vbendeb): * hardcoded frequency and mode - we might need to find a way * to configure this */ ds->freq = 10000000; ds->mode = GSBI_SPI_MODE_0; ds->allocated = 1; return &ds->slave; } printk(BIOS_ERR, "SPI error: all %d pools busy\n", i); return NULL; } /* * GSBIn SPI Hardware Initialisation */ static int spi_hw_init(struct ipq_spi_slave *ds) { int ret; if (ds->initialized) return 0; /* GSBI module configuration */ spi_reset(ds); /* Set the GSBIn QUP state */ ret = config_spi_state(ds, SPI_RESET_STATE); if (ret) return ret; /* Configure GSBI_CTRL register to set protocol_mode to SPI:011 */ clrsetbits_le32_i(ds->regs->gsbi_ctrl, PROTOCOL_CODE_MSK, PROTOCOL_CODE_SPI); /* * Configure Mini core to SPI core with Input Output enabled, * SPI master, N = 8 bits */ clrsetbits_le32_i(ds->regs->qup_config, (QUP_CONFIG_MINI_CORE_MSK | SPI_QUP_CONF_INPUT_MSK | SPI_QUP_CONF_OUTPUT_MSK | SPI_BIT_WORD_MSK), (QUP_CONFIG_MINI_CORE_SPI | SPI_QUP_CONF_NO_INPUT | SPI_QUP_CONF_NO_OUTPUT | SPI_8_BIT_WORD)); /* * Configure Input first SPI protocol, * SPI master mode and no loopback */ clrsetbits_le32_i(ds->regs->spi_config, (LOOP_BACK_MSK | SLAVE_OPERATION_MSK), (NO_LOOP_BACK | SLAVE_OPERATION)); /* * Configure SPI IO Control Register * CLK_ALWAYS_ON = 0 * MX_CS_MODE = 0 * NO_TRI_STATE = 1 */ writel_i((CLK_ALWAYS_ON | MX_CS_MODE | NO_TRI_STATE), ds->regs->io_control); /* * Configure SPI IO Modes. * OUTPUT_BIT_SHIFT_EN = 1 * INPUT_MODE = Block Mode * OUTPUT MODE = Block Mode */ clrsetbits_le32_i(ds->regs->qup_io_modes, (OUTPUT_BIT_SHIFT_MSK | INPUT_BLOCK_MODE_MSK | OUTPUT_BLOCK_MODE_MSK), (OUTPUT_BIT_SHIFT_EN | INPUT_BLOCK_MODE | OUTPUT_BLOCK_MODE)); spi_set_mode(ds, ds->mode); /* Disable Error mask */ writel_i(0, ds->regs->error_flags_en); writel_i(0, ds->regs->qup_error_flags_en); ds->initialized = 1; return SUCCESS; } int spi_claim_bus(struct spi_slave *slave) { struct ipq_spi_slave *ds = to_ipq_spi(slave); unsigned int ret; if (ds->initialized) return SUCCESS; /* GPIO Configuration for SPI port */ gsbi_pin_config(ds->slave.bus, ds->slave.cs); /* Clock configuration */ ret = gsbi_clock_init(ds); if (ret) return ret; ret = spi_hw_init(ds); if (ret) return -EIO; return SUCCESS; } void spi_release_bus(struct spi_slave *slave) { struct ipq_spi_slave *ds = to_ipq_spi(slave); /* Reset the SPI hardware */ spi_reset(ds); ds->initialized = 0; } static int spi_xfer_tx_packet(struct ipq_spi_slave *ds, const uint8_t *dout, unsigned out_bytes) { int ret; writel_i(out_bytes, ds->regs->qup_mx_output_count); ret = config_spi_state(ds, SPI_RUN_STATE); if (ret) return ret; while (out_bytes) { if (readl_i(ds->regs->qup_operational) & QUP_OUTPUT_FIFO_FULL) continue; writel_i(*dout++, ds->regs->qup_output_fifo); out_bytes--; /* Wait for output FIFO to drain. */ if (!out_bytes) while (readl_i(ds->regs->qup_operational) & QUP_OUTPUT_FIFO_NOT_EMPTY) ; } return config_spi_state(ds, SPI_RESET_STATE); } static int spi_xfer_rx_packet(struct ipq_spi_slave *ds, uint8_t *din, unsigned in_bytes) { int ret; writel_i(in_bytes, ds->regs->qup_mx_input_count); writel_i(in_bytes, ds->regs->qup_mx_output_count); ret = config_spi_state(ds, SPI_RUN_STATE); if (ret) return ret; /* Seed clocking */ writel_i(0xff, ds->regs->qup_output_fifo); while (in_bytes) { if (!(readl_i(ds->regs->qup_operational) & QUP_INPUT_FIFO_NOT_EMPTY)) continue; /* Keep it clocking */ writel_i(0xff, ds->regs->qup_output_fifo); *din++ = readl_i(ds->regs->qup_input_fifo) & 0xff; in_bytes--; } return config_spi_state(ds, SPI_RESET_STATE); } unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len) { return min(MAX_PACKET_COUNT, buf_len); } int spi_xfer(struct spi_slave *slave, const void *dout, unsigned out_bytes, void *din, unsigned in_bytes) { int ret; struct ipq_spi_slave *ds = to_ipq_spi(slave); /* Assert the chip select */ CS_change(ds->slave.bus, ds->slave.cs, CS_ASSERT); ret = config_spi_state(ds, SPI_RESET_STATE); if (ret) goto out; if (!out_bytes) goto spi_receive; /* * Let's do the write side of the transaction first. Enable output * FIFO. */ clrsetbits_le32_i(ds->regs->qup_config, SPI_QUP_CONF_OUTPUT_MSK, SPI_QUP_CONF_OUTPUT_ENA); while (out_bytes) { unsigned todo = MIN(out_bytes, MAX_PACKET_COUNT); ret = spi_xfer_tx_packet(ds, dout, todo); if (ret) break; out_bytes -= todo; dout += todo; } if (ret) goto out; spi_receive: if (!in_bytes) /* Nothing to read. */ goto out; /* Enable input FIFO */ clrsetbits_le32_i(ds->regs->qup_config, SPI_QUP_CONF_INPUT_MSK, SPI_QUP_CONF_INPUT_ENA); while (in_bytes) { unsigned todo = MIN(in_bytes, MAX_PACKET_COUNT); ret = spi_xfer_rx_packet(ds, din, todo); if (ret) break; in_bytes -= todo; din += todo; } out: /* Deassert CS */ CS_change(ds->slave.bus, ds->slave.cs, CS_DEASSERT); /* * Put the SPI Core back in the Reset State * to end the transfer */ (void)config_spi_state(ds, SPI_RESET_STATE); return ret; }