--- /dev/null
+/*
+ * au1550 psc spi controller driver
+ * may work also with au1200, au1210, au1250
+ * will not work on au1000, au1100 and au1500 (no full spi controller there)
+ *
+ * Copyright (c) 2006 ATRON electronic GmbH
+ * Author: Jan Nikitenko <jan.nikitenko@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/resource.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/dma-mapping.h>
+#include <linux/completion.h>
+#include <asm/mach-au1x00/au1000.h>
+#include <asm/mach-au1x00/au1xxx_psc.h>
+#include <asm/mach-au1x00/au1xxx_dbdma.h>
+
+#include <asm/mach-au1x00/au1550_spi.h>
+
+static unsigned usedma = 1;
+module_param(usedma, uint, 0644);
+
+/*
+#define AU1550_SPI_DEBUG_LOOPBACK
+*/
+
+
+#define AU1550_SPI_DBDMA_DESCRIPTORS 1
+#define AU1550_SPI_DMA_RXTMP_MINSIZE 2048U
+
+struct au1550_spi {
+ struct spi_bitbang bitbang;
+
+ volatile psc_spi_t __iomem *regs;
+ int irq;
+
+ unsigned len;
+ unsigned tx_count;
+ unsigned rx_count;
+ const u8 *tx;
+ u8 *rx;
+
+ void (*rx_word)(struct au1550_spi *hw);
+ void (*tx_word)(struct au1550_spi *hw);
+ int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
+ irqreturn_t (*irq_callback)(struct au1550_spi *hw);
+
+ struct completion master_done;
+
+ unsigned usedma;
+ u32 dma_tx_id;
+ u32 dma_rx_id;
+ u32 dma_tx_ch;
+ u32 dma_rx_ch;
+
+ u8 *dma_rx_tmpbuf;
+ unsigned dma_rx_tmpbuf_size;
+ u32 dma_rx_tmpbuf_addr;
+
+ struct spi_master *master;
+ struct device *dev;
+ struct au1550_spi_info *pdata;
+ struct resource *ioarea;
+};
+
+
+/* we use an 8-bit memory device for dma transfers to/from spi fifo */
+static dbdev_tab_t au1550_spi_mem_dbdev =
+{
+ .dev_id = DBDMA_MEM_CHAN,
+ .dev_flags = DEV_FLAGS_ANYUSE|DEV_FLAGS_SYNC,
+ .dev_tsize = 0,
+ .dev_devwidth = 8,
+ .dev_physaddr = 0x00000000,
+ .dev_intlevel = 0,
+ .dev_intpolarity = 0
+};
+
+static int ddma_memid; /* id to above mem dma device */
+
+static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw);
+
+
+/*
+ * compute BRG and DIV bits to setup spi clock based on main input clock rate
+ * that was specified in platform data structure
+ * according to au1550 datasheet:
+ * psc_tempclk = psc_mainclk / (2 << DIV)
+ * spiclk = psc_tempclk / (2 * (BRG + 1))
+ * BRG valid range is 4..63
+ * DIV valid range is 0..3
+ */
+static u32 au1550_spi_baudcfg(struct au1550_spi *hw, unsigned speed_hz)
+{
+ u32 mainclk_hz = hw->pdata->mainclk_hz;
+ u32 div, brg;
+
+ for (div = 0; div < 4; div++) {
+ brg = mainclk_hz / speed_hz / (4 << div);
+ /* now we have BRG+1 in brg, so count with that */
+ if (brg < (4 + 1)) {
+ brg = (4 + 1); /* speed_hz too big */
+ break; /* set lowest brg (div is == 0) */
+ }
+ if (brg <= (63 + 1))
+ break; /* we have valid brg and div */
+ }
+ if (div == 4) {
+ div = 3; /* speed_hz too small */
+ brg = (63 + 1); /* set highest brg and div */
+ }
+ brg--;
+ return PSC_SPICFG_SET_BAUD(brg) | PSC_SPICFG_SET_DIV(div);
+}
+
+static inline void au1550_spi_mask_ack_all(struct au1550_spi *hw)
+{
+ hw->regs->psc_spimsk =
+ PSC_SPIMSK_MM | PSC_SPIMSK_RR | PSC_SPIMSK_RO
+ | PSC_SPIMSK_RU | PSC_SPIMSK_TR | PSC_SPIMSK_TO
+ | PSC_SPIMSK_TU | PSC_SPIMSK_SD | PSC_SPIMSK_MD;
+ wmb(); /* drain writebuffer */
+
+ hw->regs->psc_spievent =
+ PSC_SPIEVNT_MM | PSC_SPIEVNT_RR | PSC_SPIEVNT_RO
+ | PSC_SPIEVNT_RU | PSC_SPIEVNT_TR | PSC_SPIEVNT_TO
+ | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD | PSC_SPIEVNT_MD;
+ wmb(); /* drain writebuffer */
+}
+
+static void au1550_spi_reset_fifos(struct au1550_spi *hw)
+{
+ u32 pcr;
+
+ hw->regs->psc_spipcr = PSC_SPIPCR_RC | PSC_SPIPCR_TC;
+ wmb(); /* drain writebuffer */
+ do {
+ pcr = hw->regs->psc_spipcr;
+ wmb(); /* drain writebuffer */
+ } while (pcr != 0);
+}
+
+/*
+ * dma transfers are used for the most common spi word size of 8-bits
+ * we cannot easily change already set up dma channels' width, so if we wanted
+ * dma support for more than 8-bit words (up to 24 bits), we would need to
+ * setup dma channels from scratch on each spi transfer, based on bits_per_word
+ * instead we have pre set up 8 bit dma channels supporting spi 4 to 8 bits
+ * transfers, and 9 to 24 bits spi transfers will be done in pio irq based mode
+ * callbacks to handle dma or pio are set up in au1550_spi_bits_handlers_set()
+ */
+static void au1550_spi_chipsel(struct spi_device *spi, int value)
+{
+ struct au1550_spi *hw = spi_master_get_devdata(spi->master);
+ unsigned cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
+ u32 cfg, stat;
+
+ switch (value) {
+ case BITBANG_CS_INACTIVE:
+ if (hw->pdata->deactivate_cs)
+ hw->pdata->deactivate_cs(hw->pdata, spi->chip_select,
+ cspol);
+ break;
+
+ case BITBANG_CS_ACTIVE:
+ au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
+
+ cfg = hw->regs->psc_spicfg;
+ wmb(); /* drain writebuffer */
+ hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
+ wmb(); /* drain writebuffer */
+
+ if (spi->mode & SPI_CPOL)
+ cfg |= PSC_SPICFG_BI;
+ else
+ cfg &= ~PSC_SPICFG_BI;
+ if (spi->mode & SPI_CPHA)
+ cfg &= ~PSC_SPICFG_CDE;
+ else
+ cfg |= PSC_SPICFG_CDE;
+
+ if (spi->mode & SPI_LSB_FIRST)
+ cfg |= PSC_SPICFG_MLF;
+ else
+ cfg &= ~PSC_SPICFG_MLF;
+
+ if (hw->usedma && spi->bits_per_word <= 8)
+ cfg &= ~PSC_SPICFG_DD_DISABLE;
+ else
+ cfg |= PSC_SPICFG_DD_DISABLE;
+ cfg = PSC_SPICFG_CLR_LEN(cfg);
+ cfg |= PSC_SPICFG_SET_LEN(spi->bits_per_word);
+
+ cfg = PSC_SPICFG_CLR_BAUD(cfg);
+ cfg &= ~PSC_SPICFG_SET_DIV(3);
+ cfg |= au1550_spi_baudcfg(hw, spi->max_speed_hz);
+
+ hw->regs->psc_spicfg = cfg | PSC_SPICFG_DE_ENABLE;
+ wmb(); /* drain writebuffer */
+ do {
+ stat = hw->regs->psc_spistat;
+ wmb(); /* drain writebuffer */
+ } while ((stat & PSC_SPISTAT_DR) == 0);
+
+ if (hw->pdata->activate_cs)
+ hw->pdata->activate_cs(hw->pdata, spi->chip_select,
+ cspol);
+ break;
+ }
+}
+
+static int au1550_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct au1550_spi *hw = spi_master_get_devdata(spi->master);
+ unsigned bpw, hz;
+ u32 cfg, stat;
+
+ bpw = spi->bits_per_word;
+ hz = spi->max_speed_hz;
+ if (t) {
+ if (t->bits_per_word)
+ bpw = t->bits_per_word;
+ if (t->speed_hz)
+ hz = t->speed_hz;
+ }
+
+ if (!hz)
+ return -EINVAL;
+
+ au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
+
+ cfg = hw->regs->psc_spicfg;
+ wmb(); /* drain writebuffer */
+ hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
+ wmb(); /* drain writebuffer */
+
+ if (hw->usedma && bpw <= 8)
+ cfg &= ~PSC_SPICFG_DD_DISABLE;
+ else
+ cfg |= PSC_SPICFG_DD_DISABLE;
+ cfg = PSC_SPICFG_CLR_LEN(cfg);
+ cfg |= PSC_SPICFG_SET_LEN(bpw);
+
+ cfg = PSC_SPICFG_CLR_BAUD(cfg);
+ cfg &= ~PSC_SPICFG_SET_DIV(3);
+ cfg |= au1550_spi_baudcfg(hw, hz);
+
+ hw->regs->psc_spicfg = cfg;
+ wmb(); /* drain writebuffer */
+
+ if (cfg & PSC_SPICFG_DE_ENABLE) {
+ do {
+ stat = hw->regs->psc_spistat;
+ wmb(); /* drain writebuffer */
+ } while ((stat & PSC_SPISTAT_DR) == 0);
+ }
+
+ au1550_spi_reset_fifos(hw);
+ au1550_spi_mask_ack_all(hw);
+ return 0;
+}
+
+/*
+ * for dma spi transfers, we have to setup rx channel, otherwise there is
+ * no reliable way how to recognize that spi transfer is done
+ * dma complete callbacks are called before real spi transfer is finished
+ * and if only tx dma channel is set up (and rx fifo overflow event masked)
+ * spi master done event irq is not generated unless rx fifo is empty (emptied)
+ * so we need rx tmp buffer to use for rx dma if user does not provide one
+ */
+static int au1550_spi_dma_rxtmp_alloc(struct au1550_spi *hw, unsigned size)
+{
+ hw->dma_rx_tmpbuf = kmalloc(size, GFP_KERNEL);
+ if (!hw->dma_rx_tmpbuf)
+ return -ENOMEM;
+ hw->dma_rx_tmpbuf_size = size;
+ hw->dma_rx_tmpbuf_addr = dma_map_single(hw->dev, hw->dma_rx_tmpbuf,
+ size, DMA_FROM_DEVICE);
+ if (dma_mapping_error(hw->dev, hw->dma_rx_tmpbuf_addr)) {
+ kfree(hw->dma_rx_tmpbuf);
+ hw->dma_rx_tmpbuf = 0;
+ hw->dma_rx_tmpbuf_size = 0;
+ return -EFAULT;
+ }
+ return 0;
+}
+
+static void au1550_spi_dma_rxtmp_free(struct au1550_spi *hw)
+{
+ dma_unmap_single(hw->dev, hw->dma_rx_tmpbuf_addr,
+ hw->dma_rx_tmpbuf_size, DMA_FROM_DEVICE);
+ kfree(hw->dma_rx_tmpbuf);
+ hw->dma_rx_tmpbuf = 0;
+ hw->dma_rx_tmpbuf_size = 0;
+}
+
+static int au1550_spi_dma_txrxb(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct au1550_spi *hw = spi_master_get_devdata(spi->master);
+ dma_addr_t dma_tx_addr;
+ dma_addr_t dma_rx_addr;
+ u32 res;
+
+ hw->len = t->len;
+ hw->tx_count = 0;
+ hw->rx_count = 0;
+
+ hw->tx = t->tx_buf;
+ hw->rx = t->rx_buf;
+ dma_tx_addr = t->tx_dma;
+ dma_rx_addr = t->rx_dma;
+
+ /*
+ * check if buffers are already dma mapped, map them otherwise:
+ * - first map the TX buffer, so cache data gets written to memory
+ * - then map the RX buffer, so that cache entries (with
+ * soon-to-be-stale data) get removed
+ * use rx buffer in place of tx if tx buffer was not provided
+ * use temp rx buffer (preallocated or realloc to fit) for rx dma
+ */
+ if (t->tx_buf) {
+ if (t->tx_dma == 0) { /* if DMA_ADDR_INVALID, map it */
+ dma_tx_addr = dma_map_single(hw->dev,
+ (void *)t->tx_buf,
+ t->len, DMA_TO_DEVICE);
+ if (dma_mapping_error(hw->dev, dma_tx_addr))
+ dev_err(hw->dev, "tx dma map error\n");
+ }
+ }
+
+ if (t->rx_buf) {
+ if (t->rx_dma == 0) { /* if DMA_ADDR_INVALID, map it */
+ dma_rx_addr = dma_map_single(hw->dev,
+ (void *)t->rx_buf,
+ t->len, DMA_FROM_DEVICE);
+ if (dma_mapping_error(hw->dev, dma_rx_addr))
+ dev_err(hw->dev, "rx dma map error\n");
+ }
+ } else {
+ if (t->len > hw->dma_rx_tmpbuf_size) {
+ int ret;
+
+ au1550_spi_dma_rxtmp_free(hw);
+ ret = au1550_spi_dma_rxtmp_alloc(hw, max(t->len,
+ AU1550_SPI_DMA_RXTMP_MINSIZE));
+ if (ret < 0)
+ return ret;
+ }
+ hw->rx = hw->dma_rx_tmpbuf;
+ dma_rx_addr = hw->dma_rx_tmpbuf_addr;
+ dma_sync_single_for_device(hw->dev, dma_rx_addr,
+ t->len, DMA_FROM_DEVICE);
+ }
+
+ if (!t->tx_buf) {
+ dma_sync_single_for_device(hw->dev, dma_rx_addr,
+ t->len, DMA_BIDIRECTIONAL);
+ hw->tx = hw->rx;
+ }
+
+ /* put buffers on the ring */
+ res = au1xxx_dbdma_put_dest(hw->dma_rx_ch, virt_to_phys(hw->rx),
+ t->len, DDMA_FLAGS_IE);
+ if (!res)
+ dev_err(hw->dev, "rx dma put dest error\n");
+
+ res = au1xxx_dbdma_put_source(hw->dma_tx_ch, virt_to_phys(hw->tx),
+ t->len, DDMA_FLAGS_IE);
+ if (!res)
+ dev_err(hw->dev, "tx dma put source error\n");
+
+ au1xxx_dbdma_start(hw->dma_rx_ch);
+ au1xxx_dbdma_start(hw->dma_tx_ch);
+
+ /* by default enable nearly all events interrupt */
+ hw->regs->psc_spimsk = PSC_SPIMSK_SD;
+ wmb(); /* drain writebuffer */
+
+ /* start the transfer */
+ hw->regs->psc_spipcr = PSC_SPIPCR_MS;
+ wmb(); /* drain writebuffer */
+
+ wait_for_completion(&hw->master_done);
+
+ au1xxx_dbdma_stop(hw->dma_tx_ch);
+ au1xxx_dbdma_stop(hw->dma_rx_ch);
+
+ if (!t->rx_buf) {
+ /* using the temporal preallocated and premapped buffer */
+ dma_sync_single_for_cpu(hw->dev, dma_rx_addr, t->len,
+ DMA_FROM_DEVICE);
+ }
+ /* unmap buffers if mapped above */
+ if (t->rx_buf && t->rx_dma == 0 )
+ dma_unmap_single(hw->dev, dma_rx_addr, t->len,
+ DMA_FROM_DEVICE);
+ if (t->tx_buf && t->tx_dma == 0 )
+ dma_unmap_single(hw->dev, dma_tx_addr, t->len,
+ DMA_TO_DEVICE);
+
+ return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
+}
+
+static irqreturn_t au1550_spi_dma_irq_callback(struct au1550_spi *hw)
+{
+ u32 stat, evnt;
+
+ stat = hw->regs->psc_spistat;
+ evnt = hw->regs->psc_spievent;
+ wmb(); /* drain writebuffer */
+ if ((stat & PSC_SPISTAT_DI) == 0) {
+ dev_err(hw->dev, "Unexpected IRQ!\n");
+ return IRQ_NONE;
+ }
+
+ if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
+ | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
+ | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD))
+ != 0) {
+ /*
+ * due to an spi error we consider transfer as done,
+ * so mask all events until before next transfer start
+ * and stop the possibly running dma immediately
+ */
+ au1550_spi_mask_ack_all(hw);
+ au1xxx_dbdma_stop(hw->dma_rx_ch);
+ au1xxx_dbdma_stop(hw->dma_tx_ch);
+
+ /* get number of transferred bytes */
+ hw->rx_count = hw->len - au1xxx_get_dma_residue(hw->dma_rx_ch);
+ hw->tx_count = hw->len - au1xxx_get_dma_residue(hw->dma_tx_ch);
+
+ au1xxx_dbdma_reset(hw->dma_rx_ch);
+ au1xxx_dbdma_reset(hw->dma_tx_ch);
+ au1550_spi_reset_fifos(hw);
+
+ if (evnt == PSC_SPIEVNT_RO)
+ dev_err(hw->dev,
+ "dma transfer: receive FIFO overflow!\n");
+ else
+ dev_err(hw->dev,
+ "dma transfer: unexpected SPI error "
+ "(event=0x%x stat=0x%x)!\n", evnt, stat);
+
+ complete(&hw->master_done);
+ return IRQ_HANDLED;
+ }
+
+ if ((evnt & PSC_SPIEVNT_MD) != 0) {
+ /* transfer completed successfully */
+ au1550_spi_mask_ack_all(hw);
+ hw->rx_count = hw->len;
+ hw->tx_count = hw->len;
+ complete(&hw->master_done);
+ }
+ return IRQ_HANDLED;
+}
+
+
+/* routines to handle different word sizes in pio mode */
+#define AU1550_SPI_RX_WORD(size, mask) \
+static void au1550_spi_rx_word_##size(struct au1550_spi *hw) \
+{ \
+ u32 fifoword = hw->regs->psc_spitxrx & (u32)(mask); \
+ wmb(); /* drain writebuffer */ \
+ if (hw->rx) { \
+ *(u##size *)hw->rx = (u##size)fifoword; \
+ hw->rx += (size) / 8; \
+ } \
+ hw->rx_count += (size) / 8; \
+}
+
+#define AU1550_SPI_TX_WORD(size, mask) \
+static void au1550_spi_tx_word_##size(struct au1550_spi *hw) \
+{ \
+ u32 fifoword = 0; \
+ if (hw->tx) { \
+ fifoword = *(u##size *)hw->tx & (u32)(mask); \
+ hw->tx += (size) / 8; \
+ } \
+ hw->tx_count += (size) / 8; \
+ if (hw->tx_count >= hw->len) \
+ fifoword |= PSC_SPITXRX_LC; \
+ hw->regs->psc_spitxrx = fifoword; \
+ wmb(); /* drain writebuffer */ \
+}
+
+AU1550_SPI_RX_WORD(8,0xff)
+AU1550_SPI_RX_WORD(16,0xffff)
+AU1550_SPI_RX_WORD(32,0xffffff)
+AU1550_SPI_TX_WORD(8,0xff)
+AU1550_SPI_TX_WORD(16,0xffff)
+AU1550_SPI_TX_WORD(32,0xffffff)
+
+static int au1550_spi_pio_txrxb(struct spi_device *spi, struct spi_transfer *t)
+{
+ u32 stat, mask;
+ struct au1550_spi *hw = spi_master_get_devdata(spi->master);
+
+ hw->tx = t->tx_buf;
+ hw->rx = t->rx_buf;
+ hw->len = t->len;
+ hw->tx_count = 0;
+ hw->rx_count = 0;
+
+ /* by default enable nearly all events after filling tx fifo */
+ mask = PSC_SPIMSK_SD;
+
+ /* fill the transmit FIFO */
+ while (hw->tx_count < hw->len) {
+
+ hw->tx_word(hw);
+
+ if (hw->tx_count >= hw->len) {
+ /* mask tx fifo request interrupt as we are done */
+ mask |= PSC_SPIMSK_TR;
+ }
+
+ stat = hw->regs->psc_spistat;
+ wmb(); /* drain writebuffer */
+ if (stat & PSC_SPISTAT_TF)
+ break;
+ }
+
+ /* enable event interrupts */
+ hw->regs->psc_spimsk = mask;
+ wmb(); /* drain writebuffer */
+
+ /* start the transfer */
+ hw->regs->psc_spipcr = PSC_SPIPCR_MS;
+ wmb(); /* drain writebuffer */
+
+ wait_for_completion(&hw->master_done);
+
+ return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
+}
+
+static irqreturn_t au1550_spi_pio_irq_callback(struct au1550_spi *hw)
+{
+ int busy;
+ u32 stat, evnt;
+
+ stat = hw->regs->psc_spistat;
+ evnt = hw->regs->psc_spievent;
+ wmb(); /* drain writebuffer */
+ if ((stat & PSC_SPISTAT_DI) == 0) {
+ dev_err(hw->dev, "Unexpected IRQ!\n");
+ return IRQ_NONE;
+ }
+
+ if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
+ | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
+ | PSC_SPIEVNT_SD))
+ != 0) {
+ /*
+ * due to an error we consider transfer as done,
+ * so mask all events until before next transfer start
+ */
+ au1550_spi_mask_ack_all(hw);
+ au1550_spi_reset_fifos(hw);
+ dev_err(hw->dev,
+ "pio transfer: unexpected SPI error "
+ "(event=0x%x stat=0x%x)!\n", evnt, stat);
+ complete(&hw->master_done);
+ return IRQ_HANDLED;
+ }
+
+ /*
+ * while there is something to read from rx fifo
+ * or there is a space to write to tx fifo:
+ */
+ do {
+ busy = 0;
+ stat = hw->regs->psc_spistat;
+ wmb(); /* drain writebuffer */
+
+ /*
+ * Take care to not let the Rx FIFO overflow.
+ *
+ * We only write a byte if we have read one at least. Initially,
+ * the write fifo is full, so we should read from the read fifo
+ * first.
+ * In case we miss a word from the read fifo, we should get a
+ * RO event and should back out.
+ */
+ if (!(stat & PSC_SPISTAT_RE) && hw->rx_count < hw->len) {
+ hw->rx_word(hw);
+ busy = 1;
+
+ if (!(stat & PSC_SPISTAT_TF) && hw->tx_count < hw->len)
+ hw->tx_word(hw);
+ }
+ } while (busy);
+
+ hw->regs->psc_spievent = PSC_SPIEVNT_RR | PSC_SPIEVNT_TR;
+ wmb(); /* drain writebuffer */
+
+ /*
+ * Restart the SPI transmission in case of a transmit underflow.
+ * This seems to work despite the notes in the Au1550 data book
+ * of Figure 8-4 with flowchart for SPI master operation:
+ *
+ * """Note 1: An XFR Error Interrupt occurs, unless masked,
+ * for any of the following events: Tx FIFO Underflow,
+ * Rx FIFO Overflow, or Multiple-master Error
+ * Note 2: In case of a Tx Underflow Error, all zeroes are
+ * transmitted."""
+ *
+ * By simply restarting the spi transfer on Tx Underflow Error,
+ * we assume that spi transfer was paused instead of zeroes
+ * transmittion mentioned in the Note 2 of Au1550 data book.
+ */
+ if (evnt & PSC_SPIEVNT_TU) {
+ hw->regs->psc_spievent = PSC_SPIEVNT_TU | PSC_SPIEVNT_MD;
+ wmb(); /* drain writebuffer */
+ hw->regs->psc_spipcr = PSC_SPIPCR_MS;
+ wmb(); /* drain writebuffer */
+ }
+
+ if (hw->rx_count >= hw->len) {
+ /* transfer completed successfully */
+ au1550_spi_mask_ack_all(hw);
+ complete(&hw->master_done);
+ }
+ return IRQ_HANDLED;
+}
+
+static int au1550_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct au1550_spi *hw = spi_master_get_devdata(spi->master);
+ return hw->txrx_bufs(spi, t);
+}
+
+static irqreturn_t au1550_spi_irq(int irq, void *dev)
+{
+ struct au1550_spi *hw = dev;
+ return hw->irq_callback(hw);
+}
+
+static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw)
+{
+ if (bpw <= 8) {
+ if (hw->usedma) {
+ hw->txrx_bufs = &au1550_spi_dma_txrxb;
+ hw->irq_callback = &au1550_spi_dma_irq_callback;
+ } else {
+ hw->rx_word = &au1550_spi_rx_word_8;
+ hw->tx_word = &au1550_spi_tx_word_8;
+ hw->txrx_bufs = &au1550_spi_pio_txrxb;
+ hw->irq_callback = &au1550_spi_pio_irq_callback;
+ }
+ } else if (bpw <= 16) {
+ hw->rx_word = &au1550_spi_rx_word_16;
+ hw->tx_word = &au1550_spi_tx_word_16;
+ hw->txrx_bufs = &au1550_spi_pio_txrxb;
+ hw->irq_callback = &au1550_spi_pio_irq_callback;
+ } else {
+ hw->rx_word = &au1550_spi_rx_word_32;
+ hw->tx_word = &au1550_spi_tx_word_32;
+ hw->txrx_bufs = &au1550_spi_pio_txrxb;
+ hw->irq_callback = &au1550_spi_pio_irq_callback;
+ }
+}
+
+static void au1550_spi_setup_psc_as_spi(struct au1550_spi *hw)
+{
+ u32 stat, cfg;
+
+ /* set up the PSC for SPI mode */
+ hw->regs->psc_ctrl = PSC_CTRL_DISABLE;
+ wmb(); /* drain writebuffer */
+ hw->regs->psc_sel = PSC_SEL_PS_SPIMODE;
+ wmb(); /* drain writebuffer */
+
+ hw->regs->psc_spicfg = 0;
+ wmb(); /* drain writebuffer */
+
+ hw->regs->psc_ctrl = PSC_CTRL_ENABLE;
+ wmb(); /* drain writebuffer */
+
+ do {
+ stat = hw->regs->psc_spistat;
+ wmb(); /* drain writebuffer */
+ } while ((stat & PSC_SPISTAT_SR) == 0);
+
+
+ cfg = hw->usedma ? 0 : PSC_SPICFG_DD_DISABLE;
+ cfg |= PSC_SPICFG_SET_LEN(8);
+ cfg |= PSC_SPICFG_RT_FIFO8 | PSC_SPICFG_TT_FIFO8;
+ /* use minimal allowed brg and div values as initial setting: */
+ cfg |= PSC_SPICFG_SET_BAUD(4) | PSC_SPICFG_SET_DIV(0);
+
+#ifdef AU1550_SPI_DEBUG_LOOPBACK
+ cfg |= PSC_SPICFG_LB;
+#endif
+
+ hw->regs->psc_spicfg = cfg;
+ wmb(); /* drain writebuffer */
+
+ au1550_spi_mask_ack_all(hw);
+
+ hw->regs->psc_spicfg |= PSC_SPICFG_DE_ENABLE;
+ wmb(); /* drain writebuffer */
+
+ do {
+ stat = hw->regs->psc_spistat;
+ wmb(); /* drain writebuffer */
+ } while ((stat & PSC_SPISTAT_DR) == 0);
+
+ au1550_spi_reset_fifos(hw);
+}
+
+
+static int au1550_spi_probe(struct platform_device *pdev)
+{
+ struct au1550_spi *hw;
+ struct spi_master *master;
+ struct resource *r;
+ int err = 0;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct au1550_spi));
+ if (master == NULL) {
+ dev_err(&pdev->dev, "No memory for spi_master\n");
+ err = -ENOMEM;
+ goto err_nomem;
+ }
+
+ /* the spi->mode bits understood by this driver: */
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
+ master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 24);
+
+ hw = spi_master_get_devdata(master);
+
+ hw->master = master;
+ hw->pdata = dev_get_platdata(&pdev->dev);
+ hw->dev = &pdev->dev;
+
+ if (hw->pdata == NULL) {
+ dev_err(&pdev->dev, "No platform data supplied\n");
+ err = -ENOENT;
+ goto err_no_pdata;
+ }
+
+ r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (!r) {
+ dev_err(&pdev->dev, "no IRQ\n");
+ err = -ENODEV;
+ goto err_no_iores;
+ }
+ hw->irq = r->start;
+
+ hw->usedma = 0;
+ r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
+ if (r) {
+ hw->dma_tx_id = r->start;
+ r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
+ if (r) {
+ hw->dma_rx_id = r->start;
+ if (usedma && ddma_memid) {
+ if (pdev->dev.dma_mask == NULL)
+ dev_warn(&pdev->dev, "no dma mask\n");
+ else
+ hw->usedma = 1;
+ }
+ }
+ }
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!r) {
+ dev_err(&pdev->dev, "no mmio resource\n");
+ err = -ENODEV;
+ goto err_no_iores;
+ }
+
+ hw->ioarea = request_mem_region(r->start, sizeof(psc_spi_t),
+ pdev->name);
+ if (!hw->ioarea) {
+ dev_err(&pdev->dev, "Cannot reserve iomem region\n");
+ err = -ENXIO;
+ goto err_no_iores;
+ }
+
+ hw->regs = (psc_spi_t __iomem *)ioremap(r->start, sizeof(psc_spi_t));
+ if (!hw->regs) {
+ dev_err(&pdev->dev, "cannot ioremap\n");
+ err = -ENXIO;
+ goto err_ioremap;
+ }
+
+ platform_set_drvdata(pdev, hw);
+
+ init_completion(&hw->master_done);
+
+ hw->bitbang.master = hw->master;
+ hw->bitbang.setup_transfer = au1550_spi_setupxfer;
+ hw->bitbang.chipselect = au1550_spi_chipsel;
+ hw->bitbang.txrx_bufs = au1550_spi_txrx_bufs;
+
+ if (hw->usedma) {
+ hw->dma_tx_ch = au1xxx_dbdma_chan_alloc(ddma_memid,
+ hw->dma_tx_id, NULL, (void *)hw);
+ if (hw->dma_tx_ch == 0) {
+ dev_err(&pdev->dev,
+ "Cannot allocate tx dma channel\n");
+ err = -ENXIO;
+ goto err_no_txdma;
+ }
+ au1xxx_dbdma_set_devwidth(hw->dma_tx_ch, 8);
+ if (au1xxx_dbdma_ring_alloc(hw->dma_tx_ch,
+ AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
+ dev_err(&pdev->dev,
+ "Cannot allocate tx dma descriptors\n");
+ err = -ENXIO;
+ goto err_no_txdma_descr;
+ }
+
+
+ hw->dma_rx_ch = au1xxx_dbdma_chan_alloc(hw->dma_rx_id,
+ ddma_memid, NULL, (void *)hw);
+ if (hw->dma_rx_ch == 0) {
+ dev_err(&pdev->dev,
+ "Cannot allocate rx dma channel\n");
+ err = -ENXIO;
+ goto err_no_rxdma;
+ }
+ au1xxx_dbdma_set_devwidth(hw->dma_rx_ch, 8);
+ if (au1xxx_dbdma_ring_alloc(hw->dma_rx_ch,
+ AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
+ dev_err(&pdev->dev,
+ "Cannot allocate rx dma descriptors\n");
+ err = -ENXIO;
+ goto err_no_rxdma_descr;
+ }
+
+ err = au1550_spi_dma_rxtmp_alloc(hw,
+ AU1550_SPI_DMA_RXTMP_MINSIZE);
+ if (err < 0) {
+ dev_err(&pdev->dev,
+ "Cannot allocate initial rx dma tmp buffer\n");
+ goto err_dma_rxtmp_alloc;
+ }
+ }
+
+ au1550_spi_bits_handlers_set(hw, 8);
+
+ err = request_irq(hw->irq, au1550_spi_irq, 0, pdev->name, hw);
+ if (err) {
+ dev_err(&pdev->dev, "Cannot claim IRQ\n");
+ goto err_no_irq;
+ }
+
+ master->bus_num = pdev->id;
+ master->num_chipselect = hw->pdata->num_chipselect;
+
+ /*
+ * precompute valid range for spi freq - from au1550 datasheet:
+ * psc_tempclk = psc_mainclk / (2 << DIV)
+ * spiclk = psc_tempclk / (2 * (BRG + 1))
+ * BRG valid range is 4..63
+ * DIV valid range is 0..3
+ * round the min and max frequencies to values that would still
+ * produce valid brg and div
+ */
+ {
+ int min_div = (2 << 0) * (2 * (4 + 1));
+ int max_div = (2 << 3) * (2 * (63 + 1));
+ master->max_speed_hz = hw->pdata->mainclk_hz / min_div;
+ master->min_speed_hz =
+ hw->pdata->mainclk_hz / (max_div + 1) + 1;
+ }
+
+ au1550_spi_setup_psc_as_spi(hw);
+
+ err = spi_bitbang_start(&hw->bitbang);
+ if (err) {
+ dev_err(&pdev->dev, "Failed to register SPI master\n");
+ goto err_register;
+ }
+
+ dev_info(&pdev->dev,
+ "spi master registered: bus_num=%d num_chipselect=%d\n",
+ master->bus_num, master->num_chipselect);
+
+ return 0;
+
+err_register:
+ free_irq(hw->irq, hw);
+
+err_no_irq:
+ au1550_spi_dma_rxtmp_free(hw);
+
+err_dma_rxtmp_alloc:
+err_no_rxdma_descr:
+ if (hw->usedma)
+ au1xxx_dbdma_chan_free(hw->dma_rx_ch);
+
+err_no_rxdma:
+err_no_txdma_descr:
+ if (hw->usedma)
+ au1xxx_dbdma_chan_free(hw->dma_tx_ch);
+
+err_no_txdma:
+ iounmap((void __iomem *)hw->regs);
+
+err_ioremap:
+ release_mem_region(r->start, sizeof(psc_spi_t));
+
+err_no_iores:
+err_no_pdata:
+ spi_master_put(hw->master);
+
+err_nomem:
+ return err;
+}
+
+static int au1550_spi_remove(struct platform_device *pdev)
+{
+ struct au1550_spi *hw = platform_get_drvdata(pdev);
+
+ dev_info(&pdev->dev, "spi master remove: bus_num=%d\n",
+ hw->master->bus_num);
+
+ spi_bitbang_stop(&hw->bitbang);
+ free_irq(hw->irq, hw);
+ iounmap((void __iomem *)hw->regs);
+ release_mem_region(hw->ioarea->start, sizeof(psc_spi_t));
+
+ if (hw->usedma) {
+ au1550_spi_dma_rxtmp_free(hw);
+ au1xxx_dbdma_chan_free(hw->dma_rx_ch);
+ au1xxx_dbdma_chan_free(hw->dma_tx_ch);
+ }
+
+ spi_master_put(hw->master);
+ return 0;
+}
+
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:au1550-spi");
+
+static struct platform_driver au1550_spi_drv = {
+ .probe = au1550_spi_probe,
+ .remove = au1550_spi_remove,
+ .driver = {
+ .name = "au1550-spi",
+ },
+};
+
+static int __init au1550_spi_init(void)
+{
+ /*
+ * create memory device with 8 bits dev_devwidth
+ * needed for proper byte ordering to spi fifo
+ */
+ switch (alchemy_get_cputype()) {
+ case ALCHEMY_CPU_AU1550:
+ case ALCHEMY_CPU_AU1200:
+ case ALCHEMY_CPU_AU1300:
+ break;
+ default:
+ return -ENODEV;
+ }
+
+ if (usedma) {
+ ddma_memid = au1xxx_ddma_add_device(&au1550_spi_mem_dbdev);
+ if (!ddma_memid)
+ printk(KERN_ERR "au1550-spi: cannot add memory"
+ "dbdma device\n");
+ }
+ return platform_driver_register(&au1550_spi_drv);
+}
+module_init(au1550_spi_init);
+
+static void __exit au1550_spi_exit(void)
+{
+ if (usedma && ddma_memid)
+ au1xxx_ddma_del_device(ddma_memid);
+ platform_driver_unregister(&au1550_spi_drv);
+}
+module_exit(au1550_spi_exit);
+
+MODULE_DESCRIPTION("Au1550 PSC SPI Driver");
+MODULE_AUTHOR("Jan Nikitenko <jan.nikitenko@gmail.com>");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff