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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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* SPDX-License-Identifier: GPL-2.0+
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#include <asm/mpc8xxx_spi.h>
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#define SPI_EV_NE (0x80000000 >> 22) /* Receiver Not Empty */
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#define SPI_EV_NF (0x80000000 >> 23) /* Transmitter Not Full */
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#define SPI_MODE_LOOP (0x80000000 >> 1) /* Loopback mode */
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#define SPI_MODE_REV (0x80000000 >> 5) /* Reverse mode - MSB first */
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#define SPI_MODE_MS (0x80000000 >> 6) /* Always master */
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#define SPI_MODE_EN (0x80000000 >> 7) /* Enable interface */
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#define SPI_TIMEOUT 1000
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struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
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unsigned int max_hz, unsigned int mode)
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struct spi_slave *slave;
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if (!spi_cs_is_valid(bus, cs))
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slave = spi_alloc_slave_base(bus, cs);
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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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void spi_free_slave(struct spi_slave *slave)
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volatile spi8xxx_t *spi = &((immap_t *) (CONFIG_SYS_IMMR))->spi;
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* SPI pins on the MPC83xx are not muxed, so all we do is initialize
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spi->mode = SPI_MODE_REV | SPI_MODE_MS | SPI_MODE_EN;
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spi->mode = (spi->mode & 0xfff0ffff) | (1 << 16); /* Use SYSCLK / 8
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spi->event = 0xffffffff; /* Clear all SPI events */
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spi->mask = 0x00000000; /* Mask all SPI interrupts */
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spi->com = 0; /* LST bit doesn't do anything, so disregard */
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int spi_claim_bus(struct spi_slave *slave)
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void spi_release_bus(struct spi_slave *slave)
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int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
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void *din, unsigned long flags)
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volatile spi8xxx_t *spi = &((immap_t *) (CONFIG_SYS_IMMR))->spi;
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unsigned int tmpdout, tmpdin, event;
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int numBlks = DIV_ROUND_UP(bitlen, 32);
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unsigned char charSize = 32;
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debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
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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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spi->event = 0xffffffff; /* Clear all SPI events */
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/* handle data in 32-bit chunks */
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charSize = (bitlen >= 32 ? 32 : bitlen);
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/* Shift data so it's msb-justified */
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tmpdout = *(u32 *) dout >> (32 - charSize);
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/* The LEN field of the SPMODE register is set as follows:
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* 4 < len <= 16 len - 1
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spi->mode &= ~SPI_MODE_EN;
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spi->mode = (spi->mode & 0xff0fffff) |
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spi->mode = (spi->mode & 0xff0fffff) |
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((bitlen - 1) << 20);
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spi->mode = (spi->mode & 0xff0fffff);
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/* Set up the next iteration if sending > 32 bits */
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spi->mode |= SPI_MODE_EN;
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spi->tx = tmpdout; /* Write the data out */
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debug("*** spi_xfer: ... %08x written\n", tmpdout);
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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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for (tm = 0, isRead = 0; tm < SPI_TIMEOUT; ++tm) {
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if (event & SPI_EV_NE) {
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spi->event |= SPI_EV_NE;
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*(u32 *) din = (tmpdin << (32 - charSize));
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if (charSize == 32) {
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/* Advance output buffer by 32 bits */
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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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if (isRead && (event & SPI_EV_NF))
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if (tm >= SPI_TIMEOUT)
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puts("*** spi_xfer: Time out during SPI transfer");
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debug("*** spi_xfer: transfer ended. Value=%08x\n", tmpdin);
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if (flags & SPI_XFER_END)
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spi_cs_deactivate(slave);