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76c82afef3
Instead of having a nested if block, just have two branches within the overarching if block to eliminate one nesting level. Signed-off-by: Mario Six <mario.six@gdsys.cc> Acked-by: Jagan Teki <jagan@amarulasolutions.com>
181 lines
4.3 KiB
C
181 lines
4.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (c) 2006 Ben Warren, Qstreams Networks Inc.
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* With help from the common/soft_spi and arch/powerpc/cpu/mpc8260 drivers
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*/
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#include <common.h>
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#include <malloc.h>
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#include <spi.h>
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#include <asm/mpc8xxx_spi.h>
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enum {
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SPI_EV_NE = BIT(31 - 22), /* Receiver Not Empty */
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SPI_EV_NF = BIT(31 - 23), /* Transmitter Not Full */
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};
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enum {
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SPI_MODE_LOOP = BIT(31 - 1), /* Loopback mode */
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SPI_MODE_CI = BIT(31 - 2), /* Clock invert */
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SPI_MODE_CP = BIT(31 - 3), /* Clock phase */
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SPI_MODE_DIV16 = BIT(31 - 4), /* Divide clock source by 16 */
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SPI_MODE_REV = BIT(31 - 5), /* Reverse mode - MSB first */
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SPI_MODE_MS = BIT(31 - 6), /* Always master */
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SPI_MODE_EN = BIT(31 - 7), /* Enable interface */
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SPI_MODE_LEN_MASK = 0xf00000,
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SPI_MODE_PM_MASK = 0xf0000,
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SPI_COM_LST = BIT(31 - 9),
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};
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#define SPI_TIMEOUT 1000
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struct spi_slave *spi_setup_slave(uint bus, uint cs, uint max_hz, uint mode)
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{
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struct spi_slave *slave;
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if (!spi_cs_is_valid(bus, cs))
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return NULL;
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slave = spi_alloc_slave_base(bus, cs);
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if (!slave)
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return NULL;
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/*
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* TODO: Some of the code in spi_init() should probably move
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* here, or into spi_claim_bus() below.
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*/
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return slave;
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}
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void spi_free_slave(struct spi_slave *slave)
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{
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free(slave);
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}
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void spi_init(void)
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{
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spi8xxx_t *spi = &((immap_t *)(CONFIG_SYS_IMMR))->spi;
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/*
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* SPI pins on the MPC83xx are not muxed, so all we do is initialize
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* some registers
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*/
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out_be32(&spi->mode, SPI_MODE_REV | SPI_MODE_MS | SPI_MODE_EN);
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/* Use SYSCLK / 8 (16.67MHz typ.) */
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clrsetbits_be32(&spi->mode, 0x000f0000, BIT(16));
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/* Clear all SPI events */
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setbits_be32(&spi->event, 0xffffffff);
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/* Mask all SPI interrupts */
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clrbits_be32(&spi->mask, 0xffffffff);
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/* LST bit doesn't do anything, so disregard */
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out_be32(&spi->com, 0);
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}
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int spi_claim_bus(struct spi_slave *slave)
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{
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return 0;
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}
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void spi_release_bus(struct spi_slave *slave)
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{
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}
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int spi_xfer(struct spi_slave *slave, uint bitlen, const void *dout, void *din,
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ulong flags)
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{
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spi8xxx_t *spi = &((immap_t *)(CONFIG_SYS_IMMR))->spi;
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uint tmpdout, tmpdin, event;
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int num_blks = DIV_ROUND_UP(bitlen, 32);
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int tm, is_read = 0;
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uchar char_size = 32;
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debug("%s: slave %u:%u dout %08X din %08X bitlen %u\n", __func__,
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slave->bus, slave->cs, *(uint *)dout, *(uint *)din, bitlen);
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if (flags & SPI_XFER_BEGIN)
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spi_cs_activate(slave);
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/* Clear all SPI events */
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setbits_be32(&spi->event, 0xffffffff);
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/* Handle data in 32-bit chunks */
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while (num_blks--) {
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tmpdout = 0;
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char_size = (bitlen >= 32 ? 32 : bitlen);
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/* Shift data so it's msb-justified */
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tmpdout = *(u32 *)dout >> (32 - char_size);
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/* The LEN field of the SPMODE register is set as follows:
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*
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* Bit length setting
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* len <= 4 3
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* 4 < len <= 16 len - 1
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* len > 16 0
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*/
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clrbits_be32(&spi->mode, SPI_MODE_EN);
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if (bitlen <= 4) {
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clrsetbits_be32(&spi->mode, 0x00f00000, (3 << 20));
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} else if (bitlen <= 16) {
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clrsetbits_be32(&spi->mode, 0x00f00000,
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((bitlen - 1) << 20));
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} else {
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clrbits_be32(&spi->mode, 0x00f00000);
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/* Set up the next iteration if sending > 32 bits */
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bitlen -= 32;
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dout += 4;
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}
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setbits_be32(&spi->mode, SPI_MODE_EN);
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/* Write the data out */
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out_be32(&spi->tx, tmpdout);
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debug("*** %s: ... %08x written\n", __func__, tmpdout);
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/*
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* Wait for SPI transmit to get out
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* or time out (1 second = 1000 ms)
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* The NE event must be read and cleared first
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*/
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for (tm = 0, is_read = 0; tm < SPI_TIMEOUT; ++tm) {
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event = in_be32(&spi->event);
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if (event & SPI_EV_NE) {
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tmpdin = in_be32(&spi->rx);
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setbits_be32(&spi->event, SPI_EV_NE);
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is_read = 1;
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*(u32 *)din = (tmpdin << (32 - char_size));
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if (char_size == 32) {
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/* Advance output buffer by 32 bits */
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din += 4;
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}
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}
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/*
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* Only bail when we've had both NE and NF events.
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* This will cause timeouts on RO devices, so maybe
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* in the future put an arbitrary delay after writing
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* the device. Arbitrary delays suck, though...
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*/
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if (is_read && (event & SPI_EV_NF))
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break;
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}
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if (tm >= SPI_TIMEOUT)
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debug("*** %s: Time out during SPI transfer\n",
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__func__);
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debug("*** %s: transfer ended. Value=%08x\n", __func__, tmpdin);
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}
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if (flags & SPI_XFER_END)
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spi_cs_deactivate(slave);
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return 0;
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}
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