diff options
Diffstat (limited to 'drivers/spi/designware_spi.c')
| -rw-r--r-- | drivers/spi/designware_spi.c | 426 |
1 files changed, 426 insertions, 0 deletions
diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c new file mode 100644 index 0000000000..98c9f036f2 --- /dev/null +++ b/drivers/spi/designware_spi.c @@ -0,0 +1,426 @@ +/* + * Designware master SPI core controller driver + * + * Copyright (C) 2014 Stefan Roese <sr@denx.de> + * + * Very loosely based on the Linux driver: + * drivers/spi/spi-dw.c, which is: + * Copyright (c) 2009, Intel Corporation. + * + * SPDX-License-Identifier: GPL-2.0 + */ + +#include <common.h> +#include <dm.h> +#include <errno.h> +#include <malloc.h> +#include <spi.h> +#include <fdtdec.h> +#include <linux/compat.h> +#include <asm/io.h> +#include <asm/arch/clock_manager.h> + +DECLARE_GLOBAL_DATA_PTR; + +/* Register offsets */ +#define DW_SPI_CTRL0 0x00 +#define DW_SPI_CTRL1 0x04 +#define DW_SPI_SSIENR 0x08 +#define DW_SPI_MWCR 0x0c +#define DW_SPI_SER 0x10 +#define DW_SPI_BAUDR 0x14 +#define DW_SPI_TXFLTR 0x18 +#define DW_SPI_RXFLTR 0x1c +#define DW_SPI_TXFLR 0x20 +#define DW_SPI_RXFLR 0x24 +#define DW_SPI_SR 0x28 +#define DW_SPI_IMR 0x2c +#define DW_SPI_ISR 0x30 +#define DW_SPI_RISR 0x34 +#define DW_SPI_TXOICR 0x38 +#define DW_SPI_RXOICR 0x3c +#define DW_SPI_RXUICR 0x40 +#define DW_SPI_MSTICR 0x44 +#define DW_SPI_ICR 0x48 +#define DW_SPI_DMACR 0x4c +#define DW_SPI_DMATDLR 0x50 +#define DW_SPI_DMARDLR 0x54 +#define DW_SPI_IDR 0x58 +#define DW_SPI_VERSION 0x5c +#define DW_SPI_DR 0x60 + +/* Bit fields in CTRLR0 */ +#define SPI_DFS_OFFSET 0 + +#define SPI_FRF_OFFSET 4 +#define SPI_FRF_SPI 0x0 +#define SPI_FRF_SSP 0x1 +#define SPI_FRF_MICROWIRE 0x2 +#define SPI_FRF_RESV 0x3 + +#define SPI_MODE_OFFSET 6 +#define SPI_SCPH_OFFSET 6 +#define SPI_SCOL_OFFSET 7 + +#define SPI_TMOD_OFFSET 8 +#define SPI_TMOD_MASK (0x3 << SPI_TMOD_OFFSET) +#define SPI_TMOD_TR 0x0 /* xmit & recv */ +#define SPI_TMOD_TO 0x1 /* xmit only */ +#define SPI_TMOD_RO 0x2 /* recv only */ +#define SPI_TMOD_EPROMREAD 0x3 /* eeprom read mode */ + +#define SPI_SLVOE_OFFSET 10 +#define SPI_SRL_OFFSET 11 +#define SPI_CFS_OFFSET 12 + +/* Bit fields in SR, 7 bits */ +#define SR_MASK 0x7f /* cover 7 bits */ +#define SR_BUSY (1 << 0) +#define SR_TF_NOT_FULL (1 << 1) +#define SR_TF_EMPT (1 << 2) +#define SR_RF_NOT_EMPT (1 << 3) +#define SR_RF_FULL (1 << 4) +#define SR_TX_ERR (1 << 5) +#define SR_DCOL (1 << 6) + +#define RX_TIMEOUT 1000 /* timeout in ms */ + +struct dw_spi_platdata { + s32 frequency; /* Default clock frequency, -1 for none */ + void __iomem *regs; +}; + +struct dw_spi_priv { + void __iomem *regs; + unsigned int freq; /* Default frequency */ + unsigned int mode; + + int bits_per_word; + u8 cs; /* chip select pin */ + u8 tmode; /* TR/TO/RO/EEPROM */ + u8 type; /* SPI/SSP/MicroWire */ + int len; + + u32 fifo_len; /* depth of the FIFO buffer */ + void *tx; + void *tx_end; + void *rx; + void *rx_end; +}; + +static inline u32 dw_readl(struct dw_spi_priv *priv, u32 offset) +{ + return __raw_readl(priv->regs + offset); +} + +static inline void dw_writel(struct dw_spi_priv *priv, u32 offset, u32 val) +{ + __raw_writel(val, priv->regs + offset); +} + +static inline u16 dw_readw(struct dw_spi_priv *priv, u32 offset) +{ + return __raw_readw(priv->regs + offset); +} + +static inline void dw_writew(struct dw_spi_priv *priv, u32 offset, u16 val) +{ + __raw_writew(val, priv->regs + offset); +} + +static int dw_spi_ofdata_to_platdata(struct udevice *bus) +{ + struct dw_spi_platdata *plat = bus->platdata; + const void *blob = gd->fdt_blob; + int node = bus->of_offset; + + plat->regs = (struct dw_spi *)fdtdec_get_addr(blob, node, "reg"); + + /* Use 500KHz as a suitable default */ + plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency", + 500000); + debug("%s: regs=%p max-frequency=%d\n", __func__, plat->regs, + plat->frequency); + + return 0; +} + +static inline void spi_enable_chip(struct dw_spi_priv *priv, int enable) +{ + dw_writel(priv, DW_SPI_SSIENR, (enable ? 1 : 0)); +} + +/* Restart the controller, disable all interrupts, clean rx fifo */ +static void spi_hw_init(struct dw_spi_priv *priv) +{ + spi_enable_chip(priv, 0); + dw_writel(priv, DW_SPI_IMR, 0xff); + spi_enable_chip(priv, 1); + + /* + * Try to detect the FIFO depth if not set by interface driver, + * the depth could be from 2 to 256 from HW spec + */ + if (!priv->fifo_len) { + u32 fifo; + + for (fifo = 2; fifo <= 257; fifo++) { + dw_writew(priv, DW_SPI_TXFLTR, fifo); + if (fifo != dw_readw(priv, DW_SPI_TXFLTR)) + break; + } + + priv->fifo_len = (fifo == 257) ? 0 : fifo; + dw_writew(priv, DW_SPI_TXFLTR, 0); + } + debug("%s: fifo_len=%d\n", __func__, priv->fifo_len); +} + +static int dw_spi_probe(struct udevice *bus) +{ + struct dw_spi_platdata *plat = dev_get_platdata(bus); + struct dw_spi_priv *priv = dev_get_priv(bus); + + priv->regs = plat->regs; + priv->freq = plat->frequency; + + /* Currently only bits_per_word == 8 supported */ + priv->bits_per_word = 8; + + priv->tmode = 0; /* Tx & Rx */ + + /* Basic HW init */ + spi_hw_init(priv); + + return 0; +} + +/* Return the max entries we can fill into tx fifo */ +static inline u32 tx_max(struct dw_spi_priv *priv) +{ + u32 tx_left, tx_room, rxtx_gap; + + tx_left = (priv->tx_end - priv->tx) / (priv->bits_per_word >> 3); + tx_room = priv->fifo_len - dw_readw(priv, DW_SPI_TXFLR); + + /* + * Another concern is about the tx/rx mismatch, we + * thought about using (priv->fifo_len - rxflr - txflr) as + * one maximum value for tx, but it doesn't cover the + * data which is out of tx/rx fifo and inside the + * shift registers. So a control from sw point of + * view is taken. + */ + rxtx_gap = ((priv->rx_end - priv->rx) - (priv->tx_end - priv->tx)) / + (priv->bits_per_word >> 3); + + return min3(tx_left, tx_room, (u32)(priv->fifo_len - rxtx_gap)); +} + +/* Return the max entries we should read out of rx fifo */ +static inline u32 rx_max(struct dw_spi_priv *priv) +{ + u32 rx_left = (priv->rx_end - priv->rx) / (priv->bits_per_word >> 3); + + return min_t(u32, rx_left, dw_readw(priv, DW_SPI_RXFLR)); +} + +static void dw_writer(struct dw_spi_priv *priv) +{ + u32 max = tx_max(priv); + u16 txw = 0; + + while (max--) { + /* Set the tx word if the transfer's original "tx" is not null */ + if (priv->tx_end - priv->len) { + if (priv->bits_per_word == 8) + txw = *(u8 *)(priv->tx); + else + txw = *(u16 *)(priv->tx); + } + dw_writew(priv, DW_SPI_DR, txw); + debug("%s: tx=0x%02x\n", __func__, txw); + priv->tx += priv->bits_per_word >> 3; + } +} + +static int dw_reader(struct dw_spi_priv *priv) +{ + unsigned start = get_timer(0); + u32 max; + u16 rxw; + + /* Wait for rx data to be ready */ + while (rx_max(priv) == 0) { + if (get_timer(start) > RX_TIMEOUT) + return -ETIMEDOUT; + } + + max = rx_max(priv); + + while (max--) { + rxw = dw_readw(priv, DW_SPI_DR); + debug("%s: rx=0x%02x\n", __func__, rxw); + + /* + * Care about rx only if the transfer's original "rx" is + * not null + */ + if (priv->rx_end - priv->len) { + if (priv->bits_per_word == 8) + *(u8 *)(priv->rx) = rxw; + else + *(u16 *)(priv->rx) = rxw; + } + priv->rx += priv->bits_per_word >> 3; + } + + return 0; +} + +static int poll_transfer(struct dw_spi_priv *priv) +{ + int ret; + + do { + dw_writer(priv); + ret = dw_reader(priv); + if (ret < 0) + return ret; + } while (priv->rx_end > priv->rx); + + return 0; +} + +static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen, + const void *dout, void *din, unsigned long flags) +{ + struct udevice *bus = dev->parent; + struct dw_spi_priv *priv = dev_get_priv(bus); + const u8 *tx = dout; + u8 *rx = din; + int ret = 0; + u32 cr0 = 0; + u32 cs; + + /* spi core configured to do 8 bit transfers */ + if (bitlen % 8) { + debug("Non byte aligned SPI transfer.\n"); + return -1; + } + + cr0 = (priv->bits_per_word - 1) | (priv->type << SPI_FRF_OFFSET) | + (priv->mode << SPI_MODE_OFFSET) | + (priv->tmode << SPI_TMOD_OFFSET); + + if (rx && tx) + priv->tmode = SPI_TMOD_TR; + else if (rx) + priv->tmode = SPI_TMOD_RO; + else + priv->tmode = SPI_TMOD_TO; + + cr0 &= ~SPI_TMOD_MASK; + cr0 |= (priv->tmode << SPI_TMOD_OFFSET); + + priv->len = bitlen >> 3; + debug("%s: rx=%p tx=%p len=%d [bytes]\n", __func__, rx, tx, priv->len); + + priv->tx = (void *)tx; + priv->tx_end = priv->tx + priv->len; + priv->rx = rx; + priv->rx_end = priv->rx + priv->len; + + /* Disable controller before writing control registers */ + spi_enable_chip(priv, 0); + + debug("%s: cr0=%08x\n", __func__, cr0); + /* Reprogram cr0 only if changed */ + if (dw_readw(priv, DW_SPI_CTRL0) != cr0) + dw_writew(priv, DW_SPI_CTRL0, cr0); + + /* + * Configure the desired SS (slave select 0...3) in the controller + * The DW SPI controller will activate and deactivate this CS + * automatically. So no cs_activate() etc is needed in this driver. + */ + cs = spi_chip_select(dev); + dw_writel(priv, DW_SPI_SER, 1 << cs); + + /* Enable controller after writing control registers */ + spi_enable_chip(priv, 1); + + /* Start transfer in a polling loop */ + ret = poll_transfer(priv); + + return ret; +} + +static int dw_spi_set_speed(struct udevice *bus, uint speed) +{ + struct dw_spi_platdata *plat = bus->platdata; + struct dw_spi_priv *priv = dev_get_priv(bus); + u16 clk_div; + + if (speed > plat->frequency) + speed = plat->frequency; + + /* Disable controller before writing control registers */ + spi_enable_chip(priv, 0); + + /* clk_div doesn't support odd number */ + clk_div = cm_get_spi_controller_clk_hz() / speed; + clk_div = (clk_div + 1) & 0xfffe; + dw_writel(priv, DW_SPI_BAUDR, clk_div); + + /* Enable controller after writing control registers */ + spi_enable_chip(priv, 1); + + priv->freq = speed; + debug("%s: regs=%p speed=%d clk_div=%d\n", __func__, priv->regs, + priv->freq, clk_div); + + return 0; +} + +static int dw_spi_set_mode(struct udevice *bus, uint mode) +{ + struct dw_spi_priv *priv = dev_get_priv(bus); + + /* + * Can't set mode yet. Since this depends on if rx, tx, or + * rx & tx is requested. So we have to defer this to the + * real transfer function. + */ + priv->mode = mode; + debug("%s: regs=%p, mode=%d\n", __func__, priv->regs, priv->mode); + + return 0; +} + +static const struct dm_spi_ops dw_spi_ops = { + .xfer = dw_spi_xfer, + .set_speed = dw_spi_set_speed, + .set_mode = dw_spi_set_mode, + /* + * cs_info is not needed, since we require all chip selects to be + * in the device tree explicitly + */ +}; + +static const struct udevice_id dw_spi_ids[] = { + { .compatible = "snps,dw-spi-mmio" }, + { } +}; + +U_BOOT_DRIVER(dw_spi) = { + .name = "dw_spi", + .id = UCLASS_SPI, + .of_match = dw_spi_ids, + .ops = &dw_spi_ops, + .ofdata_to_platdata = dw_spi_ofdata_to_platdata, + .platdata_auto_alloc_size = sizeof(struct dw_spi_platdata), + .priv_auto_alloc_size = sizeof(struct dw_spi_priv), + .per_child_auto_alloc_size = sizeof(struct spi_slave), + .probe = dw_spi_probe, +}; |
