diff options
Diffstat (limited to 'drivers/spi/spi-hisi-kunpeng.c')
| -rw-r--r-- | drivers/spi/spi-hisi-kunpeng.c | 505 |
1 files changed, 505 insertions, 0 deletions
diff --git a/drivers/spi/spi-hisi-kunpeng.c b/drivers/spi/spi-hisi-kunpeng.c new file mode 100644 index 000000000000..abc0cd54eee6 --- /dev/null +++ b/drivers/spi/spi-hisi-kunpeng.c @@ -0,0 +1,505 @@ +// SPDX-License-Identifier: GPL-2.0-only +// +// HiSilicon SPI Controller Driver for Kunpeng SoCs +// +// Copyright (c) 2021 HiSilicon Technologies Co., Ltd. +// Author: Jay Fang <f.fangjian@huawei.com> +// +// This code is based on spi-dw-core.c. + +#include <linux/acpi.h> +#include <linux/bitfield.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/property.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/spi/spi.h> + +/* Register offsets */ +#define HISI_SPI_CSCR 0x00 /* cs control register */ +#define HISI_SPI_CR 0x04 /* spi common control register */ +#define HISI_SPI_ENR 0x08 /* spi enable register */ +#define HISI_SPI_FIFOC 0x0c /* fifo level control register */ +#define HISI_SPI_IMR 0x10 /* interrupt mask register */ +#define HISI_SPI_DIN 0x14 /* data in register */ +#define HISI_SPI_DOUT 0x18 /* data out register */ +#define HISI_SPI_SR 0x1c /* status register */ +#define HISI_SPI_RISR 0x20 /* raw interrupt status register */ +#define HISI_SPI_ISR 0x24 /* interrupt status register */ +#define HISI_SPI_ICR 0x28 /* interrupt clear register */ +#define HISI_SPI_VERSION 0xe0 /* version register */ + +/* Bit fields in HISI_SPI_CR */ +#define CR_LOOP_MASK GENMASK(1, 1) +#define CR_CPOL_MASK GENMASK(2, 2) +#define CR_CPHA_MASK GENMASK(3, 3) +#define CR_DIV_PRE_MASK GENMASK(11, 4) +#define CR_DIV_POST_MASK GENMASK(19, 12) +#define CR_BPW_MASK GENMASK(24, 20) +#define CR_SPD_MODE_MASK GENMASK(25, 25) + +/* Bit fields in HISI_SPI_FIFOC */ +#define FIFOC_TX_MASK GENMASK(5, 3) +#define FIFOC_RX_MASK GENMASK(11, 9) + +/* Bit fields in HISI_SPI_IMR, 4 bits */ +#define IMR_RXOF BIT(0) /* Receive Overflow */ +#define IMR_RXTO BIT(1) /* Receive Timeout */ +#define IMR_RX BIT(2) /* Receive */ +#define IMR_TX BIT(3) /* Transmit */ +#define IMR_MASK (IMR_RXOF | IMR_RXTO | IMR_RX | IMR_TX) + +/* Bit fields in HISI_SPI_SR, 5 bits */ +#define SR_TXE BIT(0) /* Transmit FIFO empty */ +#define SR_TXNF BIT(1) /* Transmit FIFO not full */ +#define SR_RXNE BIT(2) /* Receive FIFO not empty */ +#define SR_RXF BIT(3) /* Receive FIFO full */ +#define SR_BUSY BIT(4) /* Busy Flag */ + +/* Bit fields in HISI_SPI_ISR, 4 bits */ +#define ISR_RXOF BIT(0) /* Receive Overflow */ +#define ISR_RXTO BIT(1) /* Receive Timeout */ +#define ISR_RX BIT(2) /* Receive */ +#define ISR_TX BIT(3) /* Transmit */ +#define ISR_MASK (ISR_RXOF | ISR_RXTO | ISR_RX | ISR_TX) + +/* Bit fields in HISI_SPI_ICR, 2 bits */ +#define ICR_RXOF BIT(0) /* Receive Overflow */ +#define ICR_RXTO BIT(1) /* Receive Timeout */ +#define ICR_MASK (ICR_RXOF | ICR_RXTO) + +#define DIV_POST_MAX 0xFF +#define DIV_POST_MIN 0x00 +#define DIV_PRE_MAX 0xFE +#define DIV_PRE_MIN 0x02 +#define CLK_DIV_MAX ((1 + DIV_POST_MAX) * DIV_PRE_MAX) +#define CLK_DIV_MIN ((1 + DIV_POST_MIN) * DIV_PRE_MIN) + +#define DEFAULT_NUM_CS 1 + +#define HISI_SPI_WAIT_TIMEOUT_MS 10UL + +enum hisi_spi_rx_level_trig { + HISI_SPI_RX_1, + HISI_SPI_RX_4, + HISI_SPI_RX_8, + HISI_SPI_RX_16, + HISI_SPI_RX_32, + HISI_SPI_RX_64, + HISI_SPI_RX_128 +}; + +enum hisi_spi_tx_level_trig { + HISI_SPI_TX_1_OR_LESS, + HISI_SPI_TX_4_OR_LESS, + HISI_SPI_TX_8_OR_LESS, + HISI_SPI_TX_16_OR_LESS, + HISI_SPI_TX_32_OR_LESS, + HISI_SPI_TX_64_OR_LESS, + HISI_SPI_TX_128_OR_LESS +}; + +enum hisi_spi_frame_n_bytes { + HISI_SPI_N_BYTES_NULL, + HISI_SPI_N_BYTES_U8, + HISI_SPI_N_BYTES_U16, + HISI_SPI_N_BYTES_U32 = 4 +}; + +/* Slave spi_dev related */ +struct hisi_chip_data { + u32 cr; + u32 speed_hz; /* baud rate */ + u16 clk_div; /* baud rate divider */ + + /* clk_div = (1 + div_post) * div_pre */ + u8 div_post; /* value from 0 to 255 */ + u8 div_pre; /* value from 2 to 254 (even only!) */ +}; + +struct hisi_spi { + struct device *dev; + + void __iomem *regs; + int irq; + u32 fifo_len; /* depth of the FIFO buffer */ + + /* Current message transfer state info */ + const void *tx; + unsigned int tx_len; + void *rx; + unsigned int rx_len; + u8 n_bytes; /* current is a 1/2/4 bytes op */ +}; + +static u32 hisi_spi_busy(struct hisi_spi *hs) +{ + return readl(hs->regs + HISI_SPI_SR) & SR_BUSY; +} + +static u32 hisi_spi_rx_not_empty(struct hisi_spi *hs) +{ + return readl(hs->regs + HISI_SPI_SR) & SR_RXNE; +} + +static u32 hisi_spi_tx_not_full(struct hisi_spi *hs) +{ + return readl(hs->regs + HISI_SPI_SR) & SR_TXNF; +} + +static void hisi_spi_flush_fifo(struct hisi_spi *hs) +{ + unsigned long limit = loops_per_jiffy << 1; + + do { + while (hisi_spi_rx_not_empty(hs)) + readl(hs->regs + HISI_SPI_DOUT); + } while (hisi_spi_busy(hs) && limit--); +} + +/* Disable the controller and all interrupts */ +static void hisi_spi_disable(struct hisi_spi *hs) +{ + writel(0, hs->regs + HISI_SPI_ENR); + writel(IMR_MASK, hs->regs + HISI_SPI_IMR); + writel(ICR_MASK, hs->regs + HISI_SPI_ICR); +} + +static u8 hisi_spi_n_bytes(struct spi_transfer *transfer) +{ + if (transfer->bits_per_word <= 8) + return HISI_SPI_N_BYTES_U8; + else if (transfer->bits_per_word <= 16) + return HISI_SPI_N_BYTES_U16; + else + return HISI_SPI_N_BYTES_U32; +} + +static void hisi_spi_reader(struct hisi_spi *hs) +{ + u32 max = min_t(u32, hs->rx_len, hs->fifo_len); + u32 rxw; + + while (hisi_spi_rx_not_empty(hs) && max--) { + rxw = readl(hs->regs + HISI_SPI_DOUT); + /* Check the transfer's original "rx" is not null */ + if (hs->rx) { + switch (hs->n_bytes) { + case HISI_SPI_N_BYTES_U8: + *(u8 *)(hs->rx) = rxw; + break; + case HISI_SPI_N_BYTES_U16: + *(u16 *)(hs->rx) = rxw; + break; + case HISI_SPI_N_BYTES_U32: + *(u32 *)(hs->rx) = rxw; + break; + } + hs->rx += hs->n_bytes; + } + --hs->rx_len; + } +} + +static void hisi_spi_writer(struct hisi_spi *hs) +{ + u32 max = min_t(u32, hs->tx_len, hs->fifo_len); + u32 txw = 0; + + while (hisi_spi_tx_not_full(hs) && max--) { + /* Check the transfer's original "tx" is not null */ + if (hs->tx) { + switch (hs->n_bytes) { + case HISI_SPI_N_BYTES_U8: + txw = *(u8 *)(hs->tx); + break; + case HISI_SPI_N_BYTES_U16: + txw = *(u16 *)(hs->tx); + break; + case HISI_SPI_N_BYTES_U32: + txw = *(u32 *)(hs->tx); + break; + } + hs->tx += hs->n_bytes; + } + writel(txw, hs->regs + HISI_SPI_DIN); + --hs->tx_len; + } +} + +static void __hisi_calc_div_reg(struct hisi_chip_data *chip) +{ + chip->div_pre = DIV_PRE_MAX; + while (chip->div_pre >= DIV_PRE_MIN) { + if (chip->clk_div % chip->div_pre == 0) + break; + + chip->div_pre -= 2; + } + + if (chip->div_pre > chip->clk_div) + chip->div_pre = chip->clk_div; + + chip->div_post = (chip->clk_div / chip->div_pre) - 1; +} + +static u32 hisi_calc_effective_speed(struct spi_controller *master, + struct hisi_chip_data *chip, u32 speed_hz) +{ + u32 effective_speed; + + /* Note clock divider doesn't support odd numbers */ + chip->clk_div = DIV_ROUND_UP(master->max_speed_hz, speed_hz) + 1; + chip->clk_div &= 0xfffe; + if (chip->clk_div > CLK_DIV_MAX) + chip->clk_div = CLK_DIV_MAX; + + effective_speed = master->max_speed_hz / chip->clk_div; + if (chip->speed_hz != effective_speed) { + __hisi_calc_div_reg(chip); + chip->speed_hz = effective_speed; + } + + return effective_speed; +} + +static u32 hisi_spi_prepare_cr(struct spi_device *spi) +{ + u32 cr = FIELD_PREP(CR_SPD_MODE_MASK, 1); + + cr |= FIELD_PREP(CR_CPHA_MASK, (spi->mode & SPI_CPHA) ? 1 : 0); + cr |= FIELD_PREP(CR_CPOL_MASK, (spi->mode & SPI_CPOL) ? 1 : 0); + cr |= FIELD_PREP(CR_LOOP_MASK, (spi->mode & SPI_LOOP) ? 1 : 0); + + return cr; +} + +static void hisi_spi_hw_init(struct hisi_spi *hs) +{ + hisi_spi_disable(hs); + + /* FIFO default config */ + writel(FIELD_PREP(FIFOC_TX_MASK, HISI_SPI_TX_64_OR_LESS) | + FIELD_PREP(FIFOC_RX_MASK, HISI_SPI_RX_16), + hs->regs + HISI_SPI_FIFOC); + + hs->fifo_len = 256; +} + +static irqreturn_t hisi_spi_irq(int irq, void *dev_id) +{ + struct spi_controller *master = dev_id; + struct hisi_spi *hs = spi_controller_get_devdata(master); + u32 irq_status = readl(hs->regs + HISI_SPI_ISR) & ISR_MASK; + + if (!irq_status) + return IRQ_NONE; + + if (!master->cur_msg) + return IRQ_HANDLED; + + /* Error handling */ + if (irq_status & ISR_RXOF) { + dev_err(hs->dev, "interrupt_transfer: fifo overflow\n"); + master->cur_msg->status = -EIO; + goto finalize_transfer; + } + + /* + * Read data from the Rx FIFO every time. If there is + * nothing left to receive, finalize the transfer. + */ + hisi_spi_reader(hs); + if (!hs->rx_len) + goto finalize_transfer; + + /* Send data out when Tx FIFO IRQ triggered */ + if (irq_status & ISR_TX) + hisi_spi_writer(hs); + + return IRQ_HANDLED; + +finalize_transfer: + hisi_spi_disable(hs); + spi_finalize_current_transfer(master); + return IRQ_HANDLED; +} + +static int hisi_spi_transfer_one(struct spi_controller *master, + struct spi_device *spi, struct spi_transfer *transfer) +{ + struct hisi_spi *hs = spi_controller_get_devdata(master); + struct hisi_chip_data *chip = spi_get_ctldata(spi); + u32 cr = chip->cr; + + /* Update per transfer options for speed and bpw */ + transfer->effective_speed_hz = + hisi_calc_effective_speed(master, chip, transfer->speed_hz); + cr |= FIELD_PREP(CR_DIV_PRE_MASK, chip->div_pre); + cr |= FIELD_PREP(CR_DIV_POST_MASK, chip->div_post); + cr |= FIELD_PREP(CR_BPW_MASK, transfer->bits_per_word - 1); + writel(cr, hs->regs + HISI_SPI_CR); + + hisi_spi_flush_fifo(hs); + + hs->n_bytes = hisi_spi_n_bytes(transfer); + hs->tx = transfer->tx_buf; + hs->tx_len = transfer->len / hs->n_bytes; + hs->rx = transfer->rx_buf; + hs->rx_len = hs->tx_len; + + /* + * Ensure that the transfer data above has been updated + * before the interrupt to start. + */ + smp_mb(); + + /* Enable all interrupts and the controller */ + writel(~IMR_MASK, hs->regs + HISI_SPI_IMR); + writel(1, hs->regs + HISI_SPI_ENR); + + return 1; +} + +static void hisi_spi_handle_err(struct spi_controller *master, + struct spi_message *msg) +{ + struct hisi_spi *hs = spi_controller_get_devdata(master); + + hisi_spi_disable(hs); + + /* + * Wait for interrupt handler that is + * already in timeout to complete. + */ + msleep(HISI_SPI_WAIT_TIMEOUT_MS); +} + +static int hisi_spi_setup(struct spi_device *spi) +{ + struct hisi_chip_data *chip; + + /* Only alloc on first setup */ + chip = spi_get_ctldata(spi); + if (!chip) { + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + spi_set_ctldata(spi, chip); + } + + chip->cr = hisi_spi_prepare_cr(spi); + + return 0; +} + +static void hisi_spi_cleanup(struct spi_device *spi) +{ + struct hisi_chip_data *chip = spi_get_ctldata(spi); + + kfree(chip); + spi_set_ctldata(spi, NULL); +} + +static int hisi_spi_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct spi_controller *master; + struct hisi_spi *hs; + int ret, irq; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + master = devm_spi_alloc_master(dev, sizeof(*hs)); + if (!master) + return -ENOMEM; + + platform_set_drvdata(pdev, master); + + hs = spi_controller_get_devdata(master); + hs->dev = dev; + hs->irq = irq; + + hs->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(hs->regs)) + return PTR_ERR(hs->regs); + + /* Specify maximum SPI clocking speed (master only) by firmware */ + ret = device_property_read_u32(dev, "spi-max-frequency", + &master->max_speed_hz); + if (ret) { + dev_err(dev, "failed to get max SPI clocking speed, ret=%d\n", + ret); + return -EINVAL; + } + + ret = device_property_read_u16(dev, "num-cs", + &master->num_chipselect); + if (ret) + master->num_chipselect = DEFAULT_NUM_CS; + + master->use_gpio_descriptors = true; + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP; + master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32); + master->bus_num = pdev->id; + master->setup = hisi_spi_setup; + master->cleanup = hisi_spi_cleanup; + master->transfer_one = hisi_spi_transfer_one; + master->handle_err = hisi_spi_handle_err; + master->dev.fwnode = dev->fwnode; + + hisi_spi_hw_init(hs); + + ret = devm_request_irq(dev, hs->irq, hisi_spi_irq, 0, dev_name(dev), + master); + if (ret < 0) { + dev_err(dev, "failed to get IRQ=%d, ret=%d\n", hs->irq, ret); + return ret; + } + + ret = spi_register_controller(master); + if (ret) { + dev_err(dev, "failed to register spi master, ret=%d\n", ret); + return ret; + } + + dev_info(dev, "hw version:0x%x max-freq:%u kHz\n", + readl(hs->regs + HISI_SPI_VERSION), + master->max_speed_hz / 1000); + + return 0; +} + +static int hisi_spi_remove(struct platform_device *pdev) +{ + struct spi_controller *master = platform_get_drvdata(pdev); + + spi_unregister_controller(master); + + return 0; +} + +static const struct acpi_device_id hisi_spi_acpi_match[] = { + {"HISI03E1", 0}, + {} +}; +MODULE_DEVICE_TABLE(acpi, hisi_spi_acpi_match); + +static struct platform_driver hisi_spi_driver = { + .probe = hisi_spi_probe, + .remove = hisi_spi_remove, + .driver = { + .name = "hisi-kunpeng-spi", + .acpi_match_table = hisi_spi_acpi_match, + }, +}; +module_platform_driver(hisi_spi_driver); + +MODULE_AUTHOR("Jay Fang <f.fangjian@huawei.com>"); +MODULE_DESCRIPTION("HiSilicon SPI Controller Driver for Kunpeng SoCs"); +MODULE_LICENSE("GPL v2"); |