[PATCH 2/2] spi: pic32-sqi: add SPI driver for PIC32 SQI controller.
From: Purna Chandra Mandal
Date: Wed Apr 13 2016 - 09:14:07 EST
This driver implements SPI master interface for Quad SPI
controller, specifically for accessing quad SPI flash.
It uses descriptor-based DMA to perform half-duplex
communication on SPI bus for single, dual and quad-lane
SPI transactions.
Signed-off-by: Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
---
drivers/spi/Kconfig | 6 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-pic32-sqi.c | 815 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 822 insertions(+)
create mode 100644 drivers/spi/spi-pic32-sqi.c
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 8a8ff50..281ed5d 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -442,6 +442,12 @@ config SPI_PIC32
help
SPI driver for Microchip PIC32 SPI master controller.
+config SPI_PIC32_SQI
+ tristate "Microchip PIC32 Quad SPI driver"
+ depends on MACH_PIC32 || COMPILE_TEST
+ help
+ SPI driver for PIC32 Quad SPI controller.
+
config SPI_PL022
tristate "ARM AMBA PL022 SSP controller"
depends on ARM_AMBA
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 06019ed..3c74d00 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_SPI_OMAP24XX) += spi-omap2-mcspi.o
obj-$(CONFIG_SPI_TI_QSPI) += spi-ti-qspi.o
obj-$(CONFIG_SPI_ORION) += spi-orion.o
obj-$(CONFIG_SPI_PIC32) += spi-pic32.o
+obj-$(CONFIG_SPI_PIC32_SQI) += spi-pic32-sqi.o
obj-$(CONFIG_SPI_PL022) += spi-pl022.o
obj-$(CONFIG_SPI_PPC4xx) += spi-ppc4xx.o
spi-pxa2xx-platform-objs := spi-pxa2xx.o spi-pxa2xx-dma.o
diff --git a/drivers/spi/spi-pic32-sqi.c b/drivers/spi/spi-pic32-sqi.c
new file mode 100644
index 0000000..bb31dc8
--- /dev/null
+++ b/drivers/spi/spi-pic32-sqi.c
@@ -0,0 +1,815 @@
+/*
+ * PIC32 Quad SPI controller driver.
+ *
+ * Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>
+ * Copyright (c) 2016, Microchip Technology Inc.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+/* SQI registers */
+#define PESQI_XIP_CONF1_REG 0x00
+#define PESQI_XIP_CONF2_REG 0x04
+#define PESQI_CONF_REG 0x08
+#define PESQI_CTRL_REG 0x0C
+#define PESQI_CLK_CTRL_REG 0x10
+#define PESQI_CMD_THRES_REG 0x14
+#define PESQI_INT_THRES_REG 0x18
+#define PESQI_INT_ENABLE_REG 0x1C
+#define PESQI_INT_STAT_REG 0x20
+#define PESQI_TX_DATA_REG 0x24
+#define PESQI_RX_DATA_REG 0x28
+#define PESQI_STAT1_REG 0x2C
+#define PESQI_STAT2_REG 0x30
+#define PESQI_BD_CTRL_REG 0x34
+#define PESQI_BD_CUR_ADDR_REG 0x38
+#define PESQI_BD_BASE_ADDR_REG 0x40
+#define PESQI_BD_STAT_REG 0x44
+#define PESQI_BD_POLL_CTRL_REG 0x48
+#define PESQI_BD_TX_DMA_STAT_REG 0x4C
+#define PESQI_BD_RX_DMA_STAT_REG 0x50
+#define PESQI_THRES_REG 0x54
+#define PESQI_INT_SIGEN_REG 0x58
+
+/* PESQI_CONF_REG fields */
+#define PESQI_MODE 0x7
+#define PESQI_MODE_BOOT 0
+#define PESQI_MODE_PIO 1
+#define PESQI_MODE_DMA 2
+#define PESQI_MODE_XIP 3
+#define PESQI_MODE_SHIFT 0
+#define PESQI_CPHA BIT(3)
+#define PESQI_CPOL BIT(4)
+#define PESQI_LSBF BIT(5)
+#define PESQI_RXLATCH BIT(7)
+#define PESQI_SERMODE BIT(8)
+#define PESQI_WP_EN BIT(9)
+#define PESQI_HOLD_EN BIT(10)
+#define PESQI_BURST_EN BIT(12)
+#define PESQI_CS_CTRL_HW BIT(15)
+#define PESQI_SOFT_RESET BIT(16)
+#define PESQI_LANES_SHIFT 20
+#define PESQI_SINGLE_LANE 0
+#define PESQI_DUAL_LANE 1
+#define PESQI_QUAD_LANE 2
+#define PESQI_CSEN_SHIFT 24
+#define PESQI_EN BIT(23)
+
+/* PESQI_CLK_CTRL_REG fields */
+#define PESQI_CLK_EN BIT(0)
+#define PESQI_CLK_STABLE BIT(1)
+#define PESQI_CLKDIV_SHIFT 8
+#define PESQI_CLKDIV 0xff
+
+/* PESQI_INT_THR/CMD_THR_REG */
+#define PESQI_TXTHR_MASK 0x1f
+#define PESQI_TXTHR_SHIFT 8
+#define PESQI_RXTHR_MASK 0x1f
+#define PESQI_RXTHR_SHIFT 0
+
+/* PESQI_INT_EN/INT_STAT/INT_SIG_EN_REG */
+#define PESQI_TXEMPTY BIT(0)
+#define PESQI_TXFULL BIT(1)
+#define PESQI_TXTHR BIT(2)
+#define PESQI_RXEMPTY BIT(3)
+#define PESQI_RXFULL BIT(4)
+#define PESQI_RXTHR BIT(5)
+#define PESQI_BDDONE BIT(9) /* BD processing complete */
+#define PESQI_PKTCOMP BIT(10) /* packet processing complete */
+#define PESQI_DMAERR BIT(11) /* error */
+
+/* PESQI_BD_CTRL_REG */
+#define PESQI_DMA_EN BIT(0) /* enable DMA engine */
+#define PESQI_POLL_EN BIT(1) /* enable polling */
+#define PESQI_BDP_START BIT(2) /* start BD processor */
+
+/* PESQI controller buffer descriptor */
+struct buf_desc {
+ u32 bd_ctrl; /* control */
+ u32 bd_status; /* reserved */
+ u32 bd_addr; /* DMA buffer addr */
+ u32 bd_nextp; /* next item in chain */
+};
+
+/* bd_ctrl */
+#define BD_BUFLEN 0x1ff
+#define BD_CBD_INT_EN BIT(16) /* Current BD is processed */
+#define BD_PKT_INT_EN BIT(17) /* All BDs of PKT processed */
+#define BD_LIFM BIT(18) /* last data of pkt */
+#define BD_LAST BIT(19) /* end of list */
+#define BD_DATA_RECV BIT(20) /* receive data */
+#define BD_DDR BIT(21) /* DDR mode */
+#define BD_DUAL BIT(22) /* Dual SPI */
+#define BD_QUAD BIT(23) /* Quad SPI */
+#define BD_LSBF BIT(25) /* LSB First */
+#define BD_STAT_CHECK BIT(27) /* Status poll */
+#define BD_DEVSEL_SHIFT 28 /* CS */
+#define BD_CS_DEASSERT BIT(30) /* de-assert CS after current BD */
+#define BD_EN BIT(31) /* BD owned by H/W */
+
+/**
+ * struct ring_desc - Representation of SQI ring descriptor
+ * @list: list element to add to free or used list.
+ * @bd: PESQI controller buffer descriptor
+ * @bd_dma: DMA address of PESQI controller buffer descriptor
+ * @xfer_len: transfer length
+ */
+struct ring_desc {
+ struct list_head list;
+ struct buf_desc *bd;
+ dma_addr_t bd_dma;
+ u32 xfer_len;
+};
+
+/* Global constants */
+#define PESQI_BD_BUF_LEN_MAX SZ_256
+#define PESQI_BD_COUNT SZ_256 /* max 64KB data per spi message */
+
+struct pic32_sqi {
+ void __iomem *regs;
+ struct clk *sys_clk;
+ struct clk *base_clk; /* drives spi clock */
+ struct spi_master *master;
+ int irq;
+ struct completion xfer_done;
+ struct ring_desc *ring;
+ void *bd;
+ dma_addr_t bd_dma;
+ struct list_head bd_list_free; /* free */
+ struct list_head bd_list_used; /* allocated */
+ struct spi_device *cur_spi;
+ u32 cur_speed;
+ u8 cur_mode;
+};
+
+static inline void pic32_setbits(void __iomem *reg, u32 set)
+{
+ writel(readl(reg) | set, reg);
+}
+
+static inline void pic32_clrbits(void __iomem *reg, u32 clr)
+{
+ writel(readl(reg) & ~clr, reg);
+}
+
+static int pic32_sqi_set_clk_rate(struct pic32_sqi *sqi, u32 sck)
+{
+ u32 val, div;
+
+ /* div = base_clk / (2 * spi_clk) */
+ div = clk_get_rate(sqi->base_clk) / (2 * sck);
+ div &= PESQI_CLKDIV;
+
+ val = readl(sqi->regs + PESQI_CLK_CTRL_REG);
+ /* apply new divider */
+ val &= ~(PESQI_CLK_STABLE | (PESQI_CLKDIV << PESQI_CLKDIV_SHIFT));
+ val |= div << PESQI_CLKDIV_SHIFT;
+ writel(val, sqi->regs + PESQI_CLK_CTRL_REG);
+
+ /* wait for stability */
+ return readl_poll_timeout(sqi->regs + PESQI_CLK_CTRL_REG, val,
+ val & PESQI_CLK_STABLE, 1, 5000);
+}
+
+static inline void pic32_sqi_enable_int(struct pic32_sqi *sqi)
+{
+ u32 mask = PESQI_DMAERR | PESQI_BDDONE | PESQI_PKTCOMP;
+
+ writel(mask, sqi->regs + PESQI_INT_ENABLE_REG);
+ /* INT_SIGEN works as interrupt-gate to INTR line */
+ writel(mask, sqi->regs + PESQI_INT_SIGEN_REG);
+}
+
+static inline void pic32_sqi_disable_int(struct pic32_sqi *sqi)
+{
+ writel(0, sqi->regs + PESQI_INT_ENABLE_REG);
+ writel(0, sqi->regs + PESQI_INT_SIGEN_REG);
+}
+
+static irqreturn_t pic32_sqi_isr(int irq, void *dev_id)
+{
+ struct pic32_sqi *sqi = dev_id;
+ u32 enable, status;
+
+ enable = readl(sqi->regs + PESQI_INT_ENABLE_REG);
+ status = readl(sqi->regs + PESQI_INT_STAT_REG);
+ if (!status)
+ return IRQ_NONE;
+
+ if (status & PESQI_DMAERR) {
+ enable = 0;
+ goto irq_done;
+ }
+
+ if (status & PESQI_TXTHR)
+ enable &= ~(PESQI_TXTHR | PESQI_TXFULL | PESQI_TXEMPTY);
+
+ if (status & PESQI_RXTHR)
+ enable &= ~(PESQI_RXTHR | PESQI_RXFULL | PESQI_RXEMPTY);
+
+ if (status & PESQI_BDDONE)
+ enable &= ~PESQI_BDDONE;
+
+ /* packet processing completed */
+ if (status & PESQI_PKTCOMP) {
+ /* mask all interrupts */
+ enable = 0;
+ /* complete trasaction */
+ complete(&sqi->xfer_done);
+ }
+
+irq_done:
+ /* interrupts are sticky, so mask when handled */
+ writel(enable, sqi->regs + PESQI_INT_ENABLE_REG);
+
+ return IRQ_HANDLED;
+}
+
+static struct ring_desc *ring_desc_get(struct pic32_sqi *sqi)
+{
+ struct ring_desc *rdesc;
+
+ if (list_empty(&sqi->bd_list_free))
+ return NULL;
+
+ rdesc = list_first_entry(&sqi->bd_list_free, struct ring_desc, list);
+ list_del(&rdesc->list);
+ list_add_tail(&rdesc->list, &sqi->bd_list_used);
+ return rdesc;
+}
+
+static void ring_desc_put(struct pic32_sqi *sqi, struct ring_desc *rdesc)
+{
+ list_del(&rdesc->list);
+ list_add(&rdesc->list, &sqi->bd_list_free);
+}
+
+static dma_addr_t pic32_sqi_map_transfer(struct pic32_sqi *sqi,
+ struct spi_transfer *transfer)
+{
+ struct device *dev = &sqi->master->dev;
+ const int len = transfer->len;
+ enum dma_data_direction dir;
+ dma_addr_t dma_buf;
+ const void *buf;
+
+ transfer->rx_dma = 0;
+ transfer->tx_dma = 0;
+
+ if (transfer->rx_buf) {
+ buf = transfer->rx_buf;
+ dir = DMA_FROM_DEVICE;
+ } else {
+ buf = transfer->tx_buf;
+ dir = DMA_TO_DEVICE;
+ }
+
+ if (is_vmalloc_addr(buf))
+ dma_buf = dma_map_page(dev, vmalloc_to_page(buf),
+ offset_in_page(buf), len, dir);
+ else
+ dma_buf = dma_map_single(dev, (void *)buf, len, dir);
+
+ if (dma_mapping_error(dev, dma_buf))
+ return 0;
+
+ if (transfer->rx_buf)
+ transfer->rx_dma = dma_buf;
+ else
+ transfer->tx_dma = dma_buf;
+
+ return dma_buf;
+}
+
+static void pic32_sqi_unmap_transfer(struct pic32_sqi *sqi,
+ struct spi_transfer *transfer)
+{
+ struct device *dev = &sqi->master->dev;
+ const int len = transfer->len;
+ enum dma_data_direction dir;
+ dma_addr_t dma_buf;
+ const void *buf;
+
+ if (transfer->rx_buf) {
+ buf = transfer->rx_buf;
+ dma_buf = transfer->rx_dma;
+ dir = DMA_FROM_DEVICE;
+ } else {
+ buf = transfer->tx_buf;
+ dma_buf = transfer->tx_dma;
+ dir = DMA_TO_DEVICE;
+ }
+
+ if (is_vmalloc_addr(buf))
+ dma_unmap_page(dev, dma_buf, len, dir);
+ else
+ dma_unmap_single(dev, dma_buf, len, dir);
+}
+
+static int pic32_sqi_one_transfer(struct pic32_sqi *sqi,
+ struct spi_message *mesg,
+ struct spi_transfer *xfer)
+{
+ struct spi_device *spi = mesg->spi;
+ struct ring_desc *rdesc;
+ dma_addr_t dma_buf;
+ int remaining, offset;
+ struct buf_desc *bd;
+ u32 bd_ctrl;
+ u32 nbits;
+
+ /* Device selection */
+ bd_ctrl = spi->chip_select << BD_DEVSEL_SHIFT;
+
+ /* half-duplex: select transfer direction and lane */
+ if (xfer->rx_buf) {
+ bd_ctrl |= BD_DATA_RECV;
+ nbits = xfer->rx_nbits;
+ } else {
+ nbits = xfer->tx_nbits;
+ }
+
+ if (nbits & SPI_NBITS_QUAD)
+ bd_ctrl |= BD_QUAD;
+ else if (nbits & SPI_NBITS_DUAL)
+ bd_ctrl |= BD_DUAL;
+
+ /* LSB first */
+ if (spi->mode & SPI_LSB_FIRST)
+ bd_ctrl |= BD_LSBF;
+
+ /* ownership to hardware */
+ bd_ctrl |= BD_EN;
+
+ dma_buf = pic32_sqi_map_transfer(sqi, xfer);
+ if (!dma_buf)
+ return -EPERM;
+
+ /* fill BDs - one BD can handle upto 256 byte of data */
+ for (offset = 0, remaining = xfer->len; remaining;) {
+ /* get ring descriptor */
+ rdesc = ring_desc_get(sqi);
+ if (!rdesc)
+ break;
+
+ rdesc->xfer_len = min_t(u32, remaining, PESQI_BD_BUF_LEN_MAX);
+
+ bd = rdesc->bd;
+
+ /* BD CTRL: length */
+ bd->bd_ctrl = bd_ctrl;
+ bd->bd_ctrl |= rdesc->xfer_len;
+
+ /* BD STAT */
+ bd->bd_status = 0;
+
+ /* BD BUFFER ADDRESS */
+ bd->bd_addr = dma_buf + offset;
+
+ remaining -= rdesc->xfer_len;
+ offset += rdesc->xfer_len;
+ }
+
+ return 0;
+}
+
+static int pic32_sqi_prepare_hardware(struct spi_master *master)
+{
+ struct pic32_sqi *sqi = spi_master_get_devdata(master);
+
+ /* enable spi interface */
+ pic32_setbits(sqi->regs + PESQI_CONF_REG, PESQI_EN);
+ /* enable spi clk */
+ pic32_setbits(sqi->regs + PESQI_CLK_CTRL_REG, PESQI_CLK_EN);
+
+ return 0;
+}
+
+static int pic32_sqi_one_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct spi_device *spi = msg->spi;
+ struct ring_desc *rdesc, *next;
+ struct spi_transfer *xfer;
+ struct pic32_sqi *sqi;
+ int ret = 0, mode;
+ u32 val;
+
+ sqi = spi_master_get_devdata(master);
+
+ reinit_completion(&sqi->xfer_done);
+ msg->actual_length = 0;
+
+ /* We can't handle spi_transfer specific "speed_hz", "bits_per_word"
+ * and "delay_usecs". But spi_device specific speed and mode change
+ * can be handled at best during spi chip-select switch.
+ */
+ if (sqi->cur_spi != spi) {
+ /* set spi speed */
+ if (sqi->cur_speed != spi->max_speed_hz) {
+ sqi->cur_speed = spi->max_speed_hz;
+ ret = pic32_sqi_set_clk_rate(sqi, spi->max_speed_hz);
+ if (ret)
+ dev_warn(&spi->dev, "set_clk, %d\n", ret);
+ }
+
+ /* set spi mode */
+ mode = spi->mode & (SPI_MODE_3 | SPI_LSB_FIRST);
+ if (sqi->cur_mode != mode) {
+ val = readl(sqi->regs + PESQI_CONF_REG);
+ val &= ~(PESQI_CPOL | PESQI_CPHA | PESQI_LSBF);
+ if (mode & SPI_CPOL)
+ val |= PESQI_CPOL;
+ if (mode & SPI_LSB_FIRST)
+ val |= PESQI_LSBF;
+ val |= PESQI_CPHA;
+ writel(val, sqi->regs + PESQI_CONF_REG);
+
+ sqi->cur_mode = mode;
+ }
+ sqi->cur_spi = spi;
+ }
+
+ /* prepare hardware desc-list(BD) for transfer(s) */
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ ret = pic32_sqi_one_transfer(sqi, msg, xfer);
+ if (ret) {
+ dev_err(&spi->dev, "xfer %p err\n", xfer);
+ goto xfer_out;
+ }
+ }
+
+ /* BDs are prepared and chained. Now mark LAST_BD, CS_DEASSERT at last
+ * element of the list.
+ */
+ rdesc = list_last_entry(&sqi->bd_list_used, struct ring_desc, list);
+ rdesc->bd->bd_ctrl |= BD_LAST | BD_CS_DEASSERT |
+ BD_LIFM | BD_PKT_INT_EN;
+
+ /* set base address BD list for DMA engine */
+ rdesc = list_first_entry(&sqi->bd_list_used, struct ring_desc, list);
+ writel(rdesc->bd_dma, sqi->regs + PESQI_BD_BASE_ADDR_REG);
+
+ /* enable interrupt */
+ pic32_sqi_enable_int(sqi);
+
+ /* enable DMA engine */
+ val = PESQI_DMA_EN | PESQI_POLL_EN | PESQI_BDP_START;
+ writel(val, sqi->regs + PESQI_BD_CTRL_REG);
+
+ /* wait for xfer completion */
+ ret = wait_for_completion_timeout(&sqi->xfer_done, 5 * HZ);
+ if (ret <= 0) {
+ dev_err(&sqi->master->dev, "wait timedout/interrupted\n");
+ ret = -EIO;
+ msg->status = ret;
+ } else {
+ /* success */
+ msg->status = 0;
+ ret = 0;
+ }
+
+ /* disable DMA */
+ writel(0, sqi->regs + PESQI_BD_CTRL_REG);
+
+ pic32_sqi_disable_int(sqi);
+
+xfer_out:
+ /* unmap dma memory */
+ list_for_each_entry_reverse(xfer, &msg->transfers, transfer_list)
+ pic32_sqi_unmap_transfer(sqi, xfer);
+
+ list_for_each_entry_safe_reverse(rdesc, next,
+ &sqi->bd_list_used, list) {
+ /* Update total byte transferred */
+ msg->actual_length += rdesc->xfer_len;
+ /* release ring descr */
+ ring_desc_put(sqi, rdesc);
+ }
+ spi_finalize_current_message(spi->master);
+
+ return ret;
+}
+
+static int pic32_sqi_unprepare_hardware(struct spi_master *master)
+{
+ struct pic32_sqi *sqi = spi_master_get_devdata(master);
+
+ /* disable clk */
+ pic32_clrbits(sqi->regs + PESQI_CLK_CTRL_REG, PESQI_CLK_EN);
+ /* disable spi */
+ pic32_clrbits(sqi->regs + PESQI_CONF_REG, PESQI_EN);
+
+ return 0;
+}
+
+/* This may be called twice for each spi dev */
+static int pic32_sqi_setup(struct spi_device *spi)
+{
+ struct pic32_sqi *sqi;
+
+ if (spi_get_ctldata(spi)) {
+ dev_err(&spi->dev, "is already associated\n");
+ return -EBUSY;
+ }
+
+ /* check word size */
+ if (!spi->bits_per_word) {
+ dev_err(&spi->dev, "No bits_per_word defined\n");
+ return -EINVAL;
+ }
+
+ /* check maximum SPI clk rate */
+ if (!spi->max_speed_hz) {
+ dev_err(&spi->dev, "No max speed HZ parameter\n");
+ return -EINVAL;
+ }
+
+ if (spi->master->max_speed_hz < spi->max_speed_hz) {
+ dev_err(&spi->dev, "max speed %u HZ is too high\n",
+ spi->max_speed_hz);
+ return -EINVAL;
+ }
+
+ sqi = spi_master_get_devdata(spi->master);
+ spi_set_ctldata(spi, (void *)sqi);
+
+ return 0;
+}
+
+static void pic32_sqi_cleanup(struct spi_device *spi)
+{
+ spi_set_ctldata(spi, (void *)NULL);
+}
+
+static int ring_desc_ring_alloc(struct pic32_sqi *sqi)
+{
+ struct ring_desc *rdesc;
+ struct buf_desc *bd;
+ int i;
+
+ /* allocate coherent memory for hardware buffer descriptors. */
+ sqi->bd = dma_zalloc_coherent(&sqi->master->dev,
+ sizeof(*bd) * PESQI_BD_COUNT,
+ &sqi->bd_dma, GFP_DMA32);
+ if (!sqi->bd) {
+ dev_err(&sqi->master->dev, "failed allocating dma buffer\n");
+ return -ENOMEM;
+ }
+
+ /* allocate software ring descriptors */
+ sqi->ring = devm_kcalloc(&sqi->master->dev, PESQI_BD_COUNT,
+ sizeof(*rdesc), GFP_KERNEL);
+ if (!sqi->ring) {
+ dma_free_coherent(&sqi->master->dev,
+ sizeof(*bd) * PESQI_BD_COUNT,
+ sqi->bd, sqi->bd_dma);
+ return -ENOMEM;
+ }
+
+ bd = (struct buf_desc *)sqi->bd;
+
+ INIT_LIST_HEAD(&sqi->bd_list_free);
+ INIT_LIST_HEAD(&sqi->bd_list_used);
+
+ /* initialize ring-desc */
+ for (i = 0, rdesc = sqi->ring; i < PESQI_BD_COUNT; i++, rdesc++) {
+ INIT_LIST_HEAD(&rdesc->list);
+ rdesc->bd = &bd[i];
+ rdesc->bd_dma = sqi->bd_dma + (void *)&bd[i] - (void *)bd;
+ list_add_tail(&rdesc->list, &sqi->bd_list_free);
+ }
+
+ /* Prepare BD: chain to next BD(s) */
+ for (i = 0, rdesc = sqi->ring; i < PESQI_BD_COUNT; i++)
+ bd[i].bd_nextp = rdesc[i + 1].bd_dma;
+ bd[PESQI_BD_COUNT - 1].bd_nextp = 0;
+
+ return 0;
+}
+
+static void ring_desc_ring_free(struct pic32_sqi *sqi)
+{
+ dma_free_coherent(&sqi->master->dev,
+ sizeof(struct buf_desc) * PESQI_BD_COUNT,
+ sqi->bd, sqi->bd_dma);
+}
+
+static void pic32_sqi_hw_init(struct pic32_sqi *sqi)
+{
+ unsigned long flags;
+ u32 val;
+
+ /* Soft-reset of PESQI controller triggers interrupt.
+ * We are not yet ready to handle them so disable CPU
+ * interrupt for the time being.
+ */
+ local_irq_save(flags);
+
+ /* assert soft-reset */
+ writel(PESQI_SOFT_RESET, sqi->regs + PESQI_CONF_REG);
+
+ /* wait until clear */
+ readl_poll_timeout_atomic(sqi->regs + PESQI_CONF_REG, val,
+ !(val & PESQI_SOFT_RESET), 1, 5000);
+
+ /* disable all interrupts */
+ pic32_sqi_disable_int(sqi);
+
+ /* Now it is safe to enable back CPU interrupt */
+ local_irq_restore(flags);
+
+ /* tx and rx fifo interrupt threshold */
+ val = readl(sqi->regs + PESQI_CMD_THRES_REG);
+ val &= ~(PESQI_TXTHR_MASK << PESQI_TXTHR_SHIFT);
+ val &= ~(PESQI_RXTHR_MASK << PESQI_RXTHR_SHIFT);
+ val |= (1U << PESQI_TXTHR_SHIFT) | (1U << PESQI_RXTHR_SHIFT);
+ writel(val, sqi->regs + PESQI_CMD_THRES_REG);
+
+ val = readl(sqi->regs + PESQI_INT_THRES_REG);
+ val &= ~(PESQI_TXTHR_MASK << PESQI_TXTHR_SHIFT);
+ val &= ~(PESQI_RXTHR_MASK << PESQI_RXTHR_SHIFT);
+ val |= (1U << PESQI_TXTHR_SHIFT) | (1U << PESQI_RXTHR_SHIFT);
+ writel(val, sqi->regs + PESQI_INT_THRES_REG);
+
+ /* default configuration */
+ val = readl(sqi->regs + PESQI_CONF_REG);
+
+ /* set mode: DMA */
+ val &= ~PESQI_MODE;
+ val |= PESQI_MODE_DMA << PESQI_MODE_SHIFT;
+ writel(val, sqi->regs + PESQI_CONF_REG);
+
+ /* DATAEN - SQIID0-ID3 */
+ val |= PESQI_QUAD_LANE << PESQI_LANES_SHIFT;
+
+ /* burst/INCR4 enable */
+ val |= PESQI_BURST_EN;
+
+ /* CSEN - all CS */
+ val |= 3U << PESQI_CSEN_SHIFT;
+ writel(val, sqi->regs + PESQI_CONF_REG);
+
+ /* write poll count */
+ writel(0, sqi->regs + PESQI_BD_POLL_CTRL_REG);
+
+ sqi->cur_speed = 0;
+ sqi->cur_mode = -1;
+}
+
+static int pic32_sqi_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct pic32_sqi *sqi;
+ struct resource *reg;
+ int ret;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(*sqi));
+ if (!master)
+ return -ENOMEM;
+
+ sqi = spi_master_get_devdata(master);
+ sqi->master = master;
+
+ reg = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ sqi->regs = devm_ioremap_resource(&pdev->dev, reg);
+ if (!sqi->regs) {
+ dev_err(&pdev->dev, "mem map failed\n");
+ ret = -EBUSY;
+ goto err_free_master;
+ }
+
+ /* irq resource */
+ sqi->irq = platform_get_irq(pdev, 0);
+ if (sqi->irq < 0) {
+ dev_err(&pdev->dev, "no irq found\n");
+ ret = sqi->irq;
+ goto err_free_master;
+ }
+
+ /* clock */
+ sqi->sys_clk = devm_clk_get(&pdev->dev, "reg_ck");
+ if (IS_ERR(sqi->sys_clk)) {
+ ret = PTR_ERR(sqi->sys_clk);
+ dev_err(&pdev->dev, "no sys_clk ?\n");
+ goto err_free_master;
+ }
+
+ sqi->base_clk = devm_clk_get(&pdev->dev, "spi_ck");
+ if (IS_ERR(sqi->base_clk)) {
+ ret = PTR_ERR(sqi->base_clk);
+ dev_err(&pdev->dev, "no base clk ?\n");
+ goto err_free_master;
+ }
+
+ clk_prepare_enable(sqi->sys_clk);
+ clk_prepare_enable(sqi->base_clk);
+
+ init_completion(&sqi->xfer_done);
+
+ /* initialize hardware */
+ pic32_sqi_hw_init(sqi);
+
+ /* allocate buffers & descriptors */
+ ret = ring_desc_ring_alloc(sqi);
+ if (ret) {
+ dev_err(&pdev->dev, "ring alloc failed\n");
+ goto err_disable_hw;
+ }
+
+ /* install irq handlers */
+ ret = devm_request_irq(&pdev->dev, sqi->irq, pic32_sqi_isr,
+ 0, dev_name(&pdev->dev), sqi);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "request-irq %d, failed ?\n", sqi->irq);
+ goto err_free_ring;
+ }
+
+ /* register master */
+ master->num_chipselect = 2;
+ master->max_speed_hz = clk_get_rate(sqi->base_clk);
+ master->dma_alignment = 32;
+ master->dev.of_node = of_node_get(pdev->dev.of_node);
+ master->mode_bits = SPI_MODE_3 | SPI_MODE_0 | SPI_TX_DUAL |
+ SPI_RX_DUAL | SPI_TX_QUAD | SPI_RX_QUAD;
+ master->flags = SPI_MASTER_HALF_DUPLEX;
+ master->setup = pic32_sqi_setup;
+ master->cleanup = pic32_sqi_cleanup;
+ master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32);
+ master->transfer_one_message = pic32_sqi_one_message;
+ master->prepare_transfer_hardware = pic32_sqi_prepare_hardware;
+ master->unprepare_transfer_hardware = pic32_sqi_unprepare_hardware;
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (ret) {
+ dev_err(&master->dev, "failed registering spi master\n");
+ goto err_free_ring;
+ }
+
+ platform_set_drvdata(pdev, sqi);
+
+ return 0;
+
+err_free_ring:
+ ring_desc_ring_free(sqi);
+err_disable_hw:
+ /* disable clk */
+ clk_disable_unprepare(sqi->base_clk);
+ clk_disable_unprepare(sqi->sys_clk);
+err_free_master:
+ spi_master_put(master);
+ return ret;
+}
+
+static int pic32_sqi_remove(struct platform_device *pdev)
+{
+ struct pic32_sqi *sqi = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(sqi->base_clk);
+ clk_disable_unprepare(sqi->sys_clk);
+
+ /* release memory */
+ ring_desc_ring_free(sqi);
+
+ return 0;
+}
+
+static const struct of_device_id pic32_sqi_of_ids[] = {
+ {.compatible = "microchip,pic32mzda-sqi",},
+ {},
+};
+MODULE_DEVICE_TABLE(of, pic32_sqi_of_ids);
+
+static struct platform_driver pic32_sqi_driver = {
+ .driver = {
+ .name = "sqi-pic32",
+ .of_match_table = of_match_ptr(pic32_sqi_of_ids),
+ },
+ .probe = pic32_sqi_probe,
+ .remove = pic32_sqi_remove,
+};
+
+module_platform_driver(pic32_sqi_driver);
+
+MODULE_AUTHOR("Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Microchip SPI driver for PIC32 SQI controller.");
+MODULE_LICENSE("GPL v2");
--
1.8.3.1