[V2 2/2] powerpc/512x: add LocalPlus Bus FIFO device driver
From: Alexander Popov
Date: Wed Jul 10 2013 - 06:19:27 EST
This is SCLPC device driver for the Freescale MPC512x.
It is needed for Direct Memory Access to the devices on LocalPlus Bus.
Signed-off-by: Alexander Popov <a13xp0p0v88@xxxxxxxxx>
---
arch/powerpc/boot/dts/mpc5121.dtsi | 8 +-
arch/powerpc/include/asm/mpc5121.h | 32 ++
arch/powerpc/platforms/512x/Kconfig | 6 +
arch/powerpc/platforms/512x/Makefile | 1 +
arch/powerpc/platforms/512x/mpc512x_lpbfifo.c | 485 ++++++++++++++++++++++++++
5 files changed, 531 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi b/arch/powerpc/boot/dts/mpc5121.dtsi
index bd14c00..6e0b0c0 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -261,7 +261,13 @@
/* LocalPlus controller */
lpc@10000 {
compatible = "fsl,mpc5121-lpc";
- reg = <0x10000 0x200>;
+ reg = <0x10000 0x100>;
+ };
+
+ sclpc@10100 {
+ compatible = "fsl,mpc512x-lpbfifo";
+ reg = <0x10100 0x50>;
+ interrupts = <7 0x8>;
};
pata@10200 {
diff --git a/arch/powerpc/include/asm/mpc5121.h b/arch/powerpc/include/asm/mpc5121.h
index 8ae133e..f416a7e 100644
--- a/arch/powerpc/include/asm/mpc5121.h
+++ b/arch/powerpc/include/asm/mpc5121.h
@@ -69,4 +69,36 @@ struct mpc512x_lpc {
int mpc512x_cs_config(unsigned int cs, u32 val);
+/*
+ * SCLPC Module (LPB FIFO)
+ */
+enum lpb_dev_portsize {
+ LPB_DEV_PORTSIZE_UNDEFINED = 0,
+ LPB_DEV_PORTSIZE_1_BYTE = 1,
+ LPB_DEV_PORTSIZE_2_BYTES = 2,
+ LPB_DEV_PORTSIZE_4_BYTES = 4,
+ LPB_DEV_PORTSIZE_8_BYTES = 8,
+};
+
+enum mpc512x_lpbfifo_req_dir {
+ MPC512X_LPBFIFO_REQ_DIR_READ,
+ MPC512X_LPBFIFO_REQ_DIR_WRITE,
+};
+
+struct mpc512x_lpbfifo_request {
+ unsigned int cs;
+ phys_addr_t bus_phys; /* physical address of some device on lpb */
+ void *ram_virt; /* virtual address of some region in ram */
+
+ /* Details of transfer */
+ u32 size;
+ enum lpb_dev_portsize portsize;
+ enum mpc512x_lpbfifo_req_dir dir;
+
+ /* Call when the transfer is finished */
+ void (*callback)(struct mpc512x_lpbfifo_request *);
+};
+
+extern int mpc512x_lpbfifo_submit(struct mpc512x_lpbfifo_request *req);
+
#endif /* __ASM_POWERPC_MPC5121_H__ */
diff --git a/arch/powerpc/platforms/512x/Kconfig b/arch/powerpc/platforms/512x/Kconfig
index fc9c1cb..0db8aa9 100644
--- a/arch/powerpc/platforms/512x/Kconfig
+++ b/arch/powerpc/platforms/512x/Kconfig
@@ -10,6 +10,12 @@ config PPC_MPC512x
select USB_EHCI_BIG_ENDIAN_MMIO
select USB_EHCI_BIG_ENDIAN_DESC
+config PPC_MPC512x_LPBFIFO
+ tristate "MPC512x LocalPlus bus FIFO driver"
+ depends on PPC_MPC512x && MPC512X_DMA
+ help
+ Enable support for the Freescale MPC512x SCLPC.
+
config MPC5121_ADS
bool "Freescale MPC5121E ADS"
depends on PPC_MPC512x
diff --git a/arch/powerpc/platforms/512x/Makefile b/arch/powerpc/platforms/512x/Makefile
index 72fb934..df932fa 100644
--- a/arch/powerpc/platforms/512x/Makefile
+++ b/arch/powerpc/platforms/512x/Makefile
@@ -2,6 +2,7 @@
# Makefile for the Freescale PowerPC 512x linux kernel.
#
obj-y += clock.o mpc512x_shared.o
+obj-$(CONFIG_PPC_MPC512x_LPBFIFO) += mpc512x_lpbfifo.o
obj-$(CONFIG_MPC5121_ADS) += mpc5121_ads.o mpc5121_ads_cpld.o
obj-$(CONFIG_MPC512x_GENERIC) += mpc512x_generic.o
obj-$(CONFIG_PDM360NG) += pdm360ng.o
diff --git a/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
new file mode 100644
index 0000000..6bd8aab
--- /dev/null
+++ b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
@@ -0,0 +1,485 @@
+/*
+ * LocalPlus Bus SCLPC driver for the Freescale MPC512x.
+ *
+ * Copyright (C) Promcontroller, 2013.
+ *
+ * Author is Alexander Popov <a13xp0p0v88@xxxxxxxxx>.
+ *
+ * The driver design is based on mpc52xx_lpbfifo driver
+ * written by Grant Likely <grant.likely@xxxxxxxxxxxx>.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <asm/io.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <asm/mpc5121.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-direction.h>
+#include <linux/dma-mapping.h>
+
+MODULE_AUTHOR("Alexander Popov <a13xp0p0v88@xxxxxxxxx>");
+MODULE_DESCRIPTION("MPC512x LocalPlus FIFO device driver");
+MODULE_LICENSE("GPL");
+
+#define DRV_NAME "mpc512x_lpbfifo"
+
+#define LPBFIFO_REG_PACKET_SIZE (0x00)
+#define LPBFIFO_REG_START_ADDRESS (0x04)
+#define LPBFIFO_REG_CONTROL (0x08)
+#define LPBFIFO_REG_ENABLE (0x0C)
+#define LPBFIFO_REG_STATUS (0x14)
+#define LPBFIFO_REG_BYTES_DONE (0x18)
+#define LPBFIFO_REG_EMB_SHARE_COUNTER (0x1C)
+#define LPBFIFO_REG_EMB_PAUSE_CONTROL (0x20)
+#define LPBFIFO_REG_FIFO_DATA (0x40)
+#define LPBFIFO_REG_FIFO_STATUS (0x44)
+#define LPBFIFO_REG_FIFO_CONTROL (0x48)
+#define LPBFIFO_REG_FIFO_ALARM (0x4C)
+
+#define DMA_LPC_CHANNEL_NUMBER 26
+#define DEFAULT_WORDS_PER_TRANSFER 1
+
+static struct mpc512x_lpbfifo {
+ struct device *dev;
+ struct resource res;
+ void __iomem *regs;
+ int irq;
+ spinlock_t lock;
+
+ /* Current state data */
+ int im_last; /* For "last one out turns off the lights" principle */
+ struct mpc512x_lpbfifo_request *req;
+ dma_addr_t ram_bus_addr;
+ struct dma_chan *chan;
+} lpbfifo;
+
+/*
+ * Before we can wrap up handling current mpc512x_lpbfifo_request
+ * and execute the callback registered in it we should:
+ * 1. recognize that everything is really done,
+ * 2. free memory and dmaengine channel.
+ *
+ * Writing from RAM to registers of some device on LPB (transmit)
+ * is not really done until the LPB FIFO completion irq triggers.
+ *
+ * For being sure that writing from registers of some device on LPB
+ * to RAM (receive) is really done we should wait
+ * for mpc512x_lpbfifo_callback() to be called by DMA driver.
+ * In this case LPB FIFO completion irq will not appear at all.
+ *
+ * Moreover, freeing memory and dmaengine channel is not safe until
+ * mpc512x_lpbfifo_callback() is called.
+ *
+ * So to make it simple:
+ * last one out turns off the lights.
+ */
+
+/*
+ * mpc512x_lpbfifo_irq - IRQ handler for LPB FIFO
+ */
+static irqreturn_t mpc512x_lpbfifo_irq(int irq, void *dev_id)
+{
+ struct mpc512x_lpbfifo_request *req;
+ unsigned long flags;
+ u32 status;
+
+ spin_lock_irqsave(&lpbfifo.lock, flags);
+
+ req = lpbfifo.req;
+ if (!req) {
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ pr_err("bogus LPBFIFO IRQ\n");
+ return IRQ_HANDLED;
+ }
+
+ if (req->dir == MPC512X_LPBFIFO_REQ_DIR_READ) {
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ pr_err("bogus LPBFIFO IRQ (we are waiting DMA IRQ)\n");
+ return IRQ_HANDLED;
+ }
+
+ /* Clear the interrupt flag */
+ status = in_8(lpbfifo.regs + LPBFIFO_REG_STATUS);
+ if (status & 0x01)
+ out_8(lpbfifo.regs + LPBFIFO_REG_STATUS, 0x01);
+ else
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+
+ if (!lpbfifo.im_last) {
+ /* I'm not the last: DMA is still in progress. */
+ lpbfifo.im_last = 1;
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ } else {
+ /* I'm last. Let's wrap up. */
+ /* Set the FIFO as idle */
+ req = lpbfifo.req;
+ lpbfifo.req = NULL;
+
+ /* The spinlock must be dropped
+ * before executing the callback,
+ * otherwise we could end up with a deadlock
+ * or nested spinlock condition. */
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ if (req->callback)
+ req->callback(req);
+ }
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * mpc512x_lpbfifo_callback is called by DMA driver
+ * when DMA transaction is finished.
+ */
+static void mpc512x_lpbfifo_callback(void *param)
+{
+ unsigned long flags;
+ struct mpc512x_lpbfifo_request *req;
+ enum dma_data_direction dir;
+
+ spin_lock_irqsave(&lpbfifo.lock, flags);
+
+ /* Free resources */
+ if (lpbfifo.req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE)
+ dir = DMA_TO_DEVICE;
+ else
+ dir = DMA_FROM_DEVICE;
+ dma_unmap_single(lpbfifo.chan->device->dev,
+ lpbfifo.ram_bus_addr, lpbfifo.req->size, dir);
+ dma_release_channel(lpbfifo.chan);
+
+ if (lpbfifo.req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE &&
+ !lpbfifo.im_last) {
+ /* I'm not the last: LPB FIFO is still writing data. */
+ lpbfifo.im_last = 1;
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ } else {
+ /* I'm the last or alone here. Let's wrap up. */
+ /* Set the FIFO as idle */
+ req = lpbfifo.req;
+ lpbfifo.req = NULL;
+
+ /* The spinlock must be dropped
+ * before executing the callback,
+ * otherwise we could end up with a deadlock
+ * or nested spinlock condition. */
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ if (req->callback)
+ req->callback(req);
+ }
+}
+
+static bool channel_filter(struct dma_chan *chan, void *filter_param)
+{
+ if (chan->chan_id == DMA_LPC_CHANNEL_NUMBER)
+ return true;
+ else
+ return false;
+}
+
+static int mpc512x_lpbfifo_kick(struct mpc512x_lpbfifo_request *req)
+{
+ u32 bits;
+ int no_incr = 0;
+ u32 bpt;
+ dma_cap_mask_t cap_mask;
+ dma_filter_fn fn = channel_filter;
+ struct dma_device *dma_dev = NULL;
+ struct scatterlist sg;
+ enum dma_data_direction dir;
+ struct dma_slave_config dma_conf = {};
+ struct dma_async_tx_descriptor *dma_tx = NULL;
+ dma_cookie_t cookie;
+ int e;
+
+ /* 1. Check requirements: */
+ /* Packet size must be a multiple of 4 bytes since
+ * FIFO Data Word Register (which provides data to DMA controller)
+ * allows only "full-word" (4 bytes) access
+ * according Reference Manual */
+ if (!IS_ALIGNED(req->size, 4)) {
+ e = -EINVAL;
+ goto err_align;
+ }
+
+ /* Physical address of the device on LPB and packet size
+ * must be aligned/multiple of BPT (bytes per transaction)
+ * according Reference Manual */
+ if (req->portsize != LPB_DEV_PORTSIZE_UNDEFINED) {
+ bpt = req->portsize;
+ no_incr = 1;
+ } else
+ bpt = DEFAULT_WORDS_PER_TRANSFER << 2; /* makes life easier */
+
+ if (!IS_ALIGNED(req->bus_phys | req->size, bpt)) {
+ e = -EFAULT;
+ goto err_align;
+ }
+
+ /* 2. Prepare DMA */
+ dma_cap_zero(cap_mask);
+ dma_cap_set(DMA_SLAVE, cap_mask);
+ lpbfifo.chan = dma_request_channel(cap_mask, fn, NULL);
+ if (!lpbfifo.chan) {
+ e = -ENODEV;
+ goto err_align;
+ }
+ dma_dev = lpbfifo.chan->device;
+
+ sg_init_table(&sg, 1);
+ if (req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE)
+ dir = DMA_TO_DEVICE;
+ else
+ dir = DMA_FROM_DEVICE;
+ sg_dma_address(&sg) = dma_map_single(dma_dev->dev,
+ req->ram_virt, req->size, dir);
+ if (dma_mapping_error(dma_dev->dev, sg_dma_address(&sg))) {
+ pr_err("dma_mapping_error\n");
+ e = -EFAULT;
+ goto err_dma_map;
+ }
+ lpbfifo.ram_bus_addr = sg_dma_address(&sg); /* will free it later */
+ sg_dma_len(&sg) = req->size;
+
+ /* We should limit the maximum number of words
+ * (units with FIFO Data Register size)
+ * that can be read from / written to the FIFO
+ * in one DMA burst.
+ * This measure and FIFO watermarks will prevent
+ * DMA controller from overtaking FIFO
+ * and causing FIFO underflow / overflow error. */
+ dma_conf.dst_maxburst = DEFAULT_WORDS_PER_TRANSFER;
+ dma_conf.src_maxburst = DEFAULT_WORDS_PER_TRANSFER;
+
+ if (req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE) {
+ dma_conf.direction = DMA_MEM_TO_DEV;
+ dma_conf.dst_addr = lpbfifo.res.start + LPBFIFO_REG_FIFO_DATA;
+ } else {
+ dma_conf.direction = DMA_DEV_TO_MEM;
+ dma_conf.src_addr = lpbfifo.res.start + LPBFIFO_REG_FIFO_DATA;
+ }
+ dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+
+ /* Make DMA channel work with LPB FIFO data register */
+ if (dma_dev->device_control(lpbfifo.chan,
+ DMA_SLAVE_CONFIG, (unsigned long)&dma_conf)) {
+ goto err_dma_prep;
+ }
+
+ dma_tx = dmaengine_prep_slave_sg(lpbfifo.chan, &sg,
+ 1, dma_conf.direction, 0);
+ if (!dma_tx) {
+ pr_err("dmaengine_prep_slave_sg failed\n");
+ e = -ENOSPC;
+ goto err_dma_prep;
+ }
+
+ dma_tx->callback = mpc512x_lpbfifo_callback;
+ dma_tx->callback_param = NULL;
+
+ /* 3. Prepare FIFO */
+ /* Set and clear the reset bits;
+ * is good practice in Reference Manual */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x0);
+
+ /* Configure the watermarks.
+ *
+ * RAM->DMA->FIFO->LPB_DEV (write):
+ * High watermark (7 * 4) free bytes (according Reference Manual)
+ * Low watermark 996 bytes (whole FIFO - 28 bytes)
+ *
+ * LPB_DEV->FIFO->DMA->RAM (read):
+ * High watermark (1024 - 4) free bytes
+ * (whole FIFO - DEFAULT_WORDS_PER_TRANSFER)
+ * Low watermark 0 bytes
+ */
+ if (req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE) {
+ out_be16(lpbfifo.regs + LPBFIFO_REG_FIFO_CONTROL, 0x0700);
+ out_be32(lpbfifo.regs + LPBFIFO_REG_FIFO_ALARM, 0x000003e4);
+ } else {
+ out_be16(lpbfifo.regs + LPBFIFO_REG_FIFO_CONTROL, 0x0);
+ out_be32(lpbfifo.regs + LPBFIFO_REG_FIFO_ALARM, 0x000003fc);
+ }
+
+ /* Start address is a physical address of the region
+ * which belongs to the device on localplus bus */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_START_ADDRESS, req->bus_phys);
+
+ /* Configure chip select, transfer direction,
+ * address increment option and bytes per transfer option */
+ bits = (req->cs & 0x7) << 24;
+ if (req->dir == MPC512X_LPBFIFO_REQ_DIR_READ)
+ bits |= 3 << 16; /* read mode bit and flush bit */
+ if (no_incr)
+ bits |= 1 << 8;
+ bits |= bpt & 0x3f;
+ out_be32(lpbfifo.regs + LPBFIFO_REG_CONTROL, bits);
+
+ /* Unmask irqs */
+ bits = 0x00000201; /* set error irq & master enabled bit */
+ if (req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE)
+ bits |= 0x00000100; /* set completion irq too */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, bits);
+
+ /* 4. Set packet size and kick FIFO off */
+ bits = req->size;
+ bits |= (1<<31); /* set restart bit */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, bits);
+
+
+ /* 5. Then kick DMA off */
+ cookie = dma_tx->tx_submit(dma_tx);
+ if (dma_submit_error(cookie)) {
+ pr_err("DMA tx_submit failed\n");
+ e = -ENOSPC;
+ goto err_dma_submit;
+ }
+
+ return 0;
+
+ err_dma_submit:
+
+ err_dma_prep:
+ dma_unmap_single(dma_dev->dev, sg_dma_address(&sg), req->size, dir);
+
+ err_dma_map:
+ sg_dma_address(&sg) = 0;
+ dma_release_channel(lpbfifo.chan);
+
+ err_align:
+ return e;
+}
+
+int mpc512x_lpbfifo_submit(struct mpc512x_lpbfifo_request *req)
+{
+ unsigned long flags;
+ int result = 0;
+
+ if (!lpbfifo.regs)
+ return -ENODEV;
+
+ spin_lock_irqsave(&lpbfifo.lock, flags);
+
+ /* A transfer is in progress
+ * if the req pointer is already set */
+ if (lpbfifo.req) {
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ return -EBUSY;
+ }
+
+ /* (128 kBytes - 4 Bytes) is a maximum packet size
+ * that LPB FIFO and DMA controller can handle together
+ * while exchanging DEFAULT_WORDS_PER_TRANSFER = 1
+ * per hardware request */
+ if (req->size > 131068) {
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ return -ENOSPC;
+ }
+
+ /* Setup the transfer */
+ lpbfifo.im_last = 0;
+ lpbfifo.req = req;
+
+ result = mpc512x_lpbfifo_kick(req);
+ if (result != 0)
+ lpbfifo.req = NULL; /* Set the FIFO as idle */
+
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+ return result;
+}
+EXPORT_SYMBOL(mpc512x_lpbfifo_submit);
+
+static int mpc512x_lpbfifo_probe(struct platform_device *pdev)
+{
+ struct resource *r = &lpbfifo.res;
+ int e = 0, rc = -ENOMEM;
+
+ if (of_address_to_resource(pdev->dev.of_node, 0, r)) {
+ e = -ENODEV;
+ goto err_res;
+ }
+
+ if (!request_mem_region(r->start, resource_size(r), DRV_NAME)) {
+ e = -EBUSY;
+ goto err_res;
+ }
+
+ lpbfifo.irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
+ if (!lpbfifo.irq) {
+ e = -ENODEV;
+ goto err_res;
+ }
+
+ lpbfifo.regs = ioremap(r->start, resource_size(r));
+ if (!lpbfifo.regs) {
+ e = -ENOMEM;
+ goto err_regs;
+ }
+
+ spin_lock_init(&lpbfifo.lock);
+
+ /* Put FIFO into reset state */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+
+ lpbfifo.dev = &pdev->dev;
+
+ rc = request_irq(lpbfifo.irq,
+ mpc512x_lpbfifo_irq, 0, DRV_NAME, &lpbfifo);
+ if (rc) {
+ e = -ENODEV;
+ goto err_irq;
+ }
+
+ return 0;
+
+ err_irq:
+ iounmap(lpbfifo.regs);
+ lpbfifo.regs = NULL;
+
+ err_regs:
+ release_mem_region(r->start, resource_size(r));
+
+ err_res:
+ dev_err(&pdev->dev, "mpc512x_lpbfifo_probe() failed\n");
+ return e;
+}
+
+static int mpc512x_lpbfifo_remove(struct platform_device *pdev)
+{
+ /* Put FIFO in reset */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+
+ free_irq(lpbfifo.irq, &lpbfifo);
+ iounmap(lpbfifo.regs);
+ release_mem_region(lpbfifo.res.start, resource_size(&lpbfifo.res));
+ lpbfifo.regs = NULL;
+ lpbfifo.dev = NULL;
+
+ return 0;
+}
+
+static const struct of_device_id mpc512x_lpbfifo_match[] = {
+ { .compatible = "fsl,mpc512x-lpbfifo", },
+ {},
+};
+
+static struct platform_driver mpc512x_lpbfifo_driver = {
+ .probe = mpc512x_lpbfifo_probe,
+ .remove = mpc512x_lpbfifo_remove,
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = mpc512x_lpbfifo_match,
+ },
+};
+module_platform_driver(mpc512x_lpbfifo_driver);
--
1.7.11.3
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