Date:	Wed, 26 Nov 2008 14:40:54 -0800
From:	Inaky Perez-Gonzalez <inaky@...ux.intel.com>
To:	netdev@...r.kernel.org
Cc:	wimax@...uxwimax.org
Subject: [PATCH 35/39] i2400m/SDIO: read transactions from the SDIO device

This code implements reading from the SDIO device; when data is ready
the SDIO IRQ is fired and that will allocate an skb, put all the data
there and then pass it to the generic driver for processing and delivery.

Signed-off-by: Inaky Perez-Gonzalez <inaky@...ux.intel.com>
---
 drivers/net/wimax/i2400m/sdio-rx.c |  255 ++++++++++++++++++++++++++++++++++++
 1 files changed, 255 insertions(+), 0 deletions(-)
 create mode 100644 drivers/net/wimax/i2400m/sdio-rx.c

diff --git a/drivers/net/wimax/i2400m/sdio-rx.c b/drivers/net/wimax/i2400m/sdio-rx.c
new file mode 100644
index 0000000..237279d
--- /dev/null
+++ b/drivers/net/wimax/i2400m/sdio-rx.c
@@ -0,0 +1,255 @@
+/*
+ * Intel Wireless WiMAX Connection 2400m
+ * SDIO RX handling
+ *
+ *
+ * Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *   * Neither the name of Intel Corporation nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ * Intel Corporation <linux-wimax@...el.com>
+ * Dirk Brandewie <dirk.j.brandewie@...el.com>
+ *  - Initial implementation
+ *
+ *
+ * This handles the RX path on SDIO.
+ *
+ * The SDIO bus driver calls the "irq" routine when data is available.
+ * This is not a traditional interrupt routine since the SDIO bus
+ * driver calls us from its irq thread context.  Because of this
+ * sleeping in the SDIO RX IRQ routine is okay.
+ *
+ * From there on, we obtain the size of the data that is available,
+ * allocate an skb, copy it and then pass it to the generic driver's
+ * RX routine [i2400m_rx()].
+ *
+ * ROADMAP
+ *
+ * i2400ms_irq()
+ *   i2400ms_rx()
+ *     __i2400ms_rx_get_size()
+ *     i2400m_rx()
+ *
+ * i2400ms_rx_setup()
+ *
+ * i2400ms_rx_release()
+ */
+#include <linux/workqueue.h>
+#include <linux/wait.h>
+#include <linux/skbuff.h>
+#include <linux/mmc/sdio.h>
+#include <linux/mmc/sdio_func.h>
+#include "i2400m-sdio.h"
+
+#define D_SUBMODULE sdio_rx
+#include "sdio-debug-levels.h"
+
+
+/*
+ * Read and return the amount of bytes available for RX
+ *
+ * The RX size has to be read like this: byte reads of three
+ * sequential locations; then glue'em together.
+ *
+ * sdio_readl() doesn't work.
+ */
+ssize_t __i2400ms_rx_get_size(struct i2400ms *i2400ms)
+{
+	int ret, cnt, val;
+	ssize_t rx_size;
+	unsigned xfer_size_addr;
+	struct sdio_func *func = i2400ms->func;
+	struct device *dev = &i2400ms->func->dev;
+
+	d_fnstart(7, dev, "(i2400ms %p)\n", i2400ms);
+	xfer_size_addr = I2400MS_INTR_GET_SIZE_ADDR;
+	rx_size = 0;
+	for (cnt = 0; cnt < 3; cnt++) {
+		val = sdio_readb(func, xfer_size_addr + cnt, &ret);
+		if (ret < 0) {
+			dev_err(dev, "RX: Can't read byte %d of RX size from "
+				"0x%08x: %d\n", cnt, xfer_size_addr + cnt, ret);
+			rx_size = ret;
+			goto error_read;
+		}
+		rx_size = rx_size << 8 | (val & 0xff);
+	}
+	d_printf(6, dev, "RX: rx_size is %ld\n", (long) rx_size);
+error_read:
+	d_fnend(7, dev, "(i2400ms %p) = %ld\n", i2400ms, (long) rx_size);
+	return rx_size;
+}
+
+
+/*
+ * Read data from the device (when in normal)
+ *
+ * Allocate an SKB of the right size, read the data in and then
+ * deliver it to the generic layer.
+ *
+ * We also check for a reboot barker. That means the device died and
+ * we have to reboot it.
+ */
+static
+void i2400ms_rx(struct i2400ms *i2400ms)
+{
+	int ret;
+	struct sdio_func *func = i2400ms->func;
+	struct device *dev = &func->dev;
+	struct i2400m *i2400m = &i2400ms->i2400m;
+	struct sk_buff *skb;
+	ssize_t rx_size;
+
+	d_fnstart(7, dev, "(i2400ms %p)\n", i2400ms);
+	rx_size = __i2400ms_rx_get_size(i2400ms);
+	if (rx_size < 0) {
+		ret = rx_size;
+		goto error_get_size;
+	}
+	ret = -ENOMEM;
+	skb = alloc_skb(rx_size, GFP_ATOMIC);
+	if (NULL == skb) {
+		dev_err(dev, "RX: unable to alloc skb\n");
+		goto error_alloc_skb;
+	}
+
+	ret = sdio_memcpy_fromio(func, skb->data,
+				 I2400MS_DATA_ADDR, rx_size);
+	if (ret < 0) {
+		dev_err(dev, "RX: SDIO data read failed: %d\n", ret);
+		goto error_memcpy_fromio;
+	}
+	/* Check if device has reset */
+	if (!memcmp(skb->data, i2400m_NBOOT_BARKER,
+		    sizeof(i2400m_NBOOT_BARKER))
+	    || !memcmp(skb->data, i2400m_SBOOT_BARKER,
+		       sizeof(i2400m_SBOOT_BARKER))) {
+		ret = i2400m_dev_reset_handle(i2400m);
+		kfree_skb(skb);
+	} else {
+		skb_put(skb, rx_size);
+		i2400m_rx(i2400m, skb);
+	}
+	d_fnend(7, dev, "(i2400ms %p) = void\n", i2400ms);
+	return;
+
+error_memcpy_fromio:
+	kfree_skb(skb);
+error_alloc_skb:
+error_get_size:
+	d_fnend(7, dev, "(i2400ms %p) = %d\n", i2400ms, ret);
+	return;
+}
+
+
+/*
+ * Process an interrupt from the SDIO card
+ *
+ * FIXME: need to process other events that are not just ready-to-read
+ *
+ * Checks there is data ready and then proceeds to read it.
+ */
+static
+void i2400ms_irq(struct sdio_func *func)
+{
+	int ret;
+	struct i2400ms *i2400ms = sdio_get_drvdata(func);
+	struct i2400m *i2400m = &i2400ms->i2400m;
+	struct device *dev = &func->dev;
+	int val;
+
+	d_fnstart(6, dev, "(i2400ms %p)\n", i2400ms);
+	val = sdio_readb(func, I2400MS_INTR_STATUS_ADDR, &ret);
+	if (ret < 0) {
+		dev_err(dev, "RX: Can't read interrupt status: %d\n", ret);
+		goto error_no_irq;
+	}
+	if (!val) {
+		dev_err(dev, "RX: BUG? got IRQ but no interrupt ready?\n");
+		goto error_no_irq;
+	}
+	sdio_writeb(func, 1, I2400MS_INTR_CLEAR_ADDR, &ret);
+	if (WARN_ON(i2400m->boot_mode != 0))
+		dev_err(dev, "RX: SW BUG? boot mode and IRQ is up?\n");
+	else
+		i2400ms_rx(i2400ms);
+error_no_irq:
+	d_fnend(6, dev, "(i2400ms %p) = void\n", i2400ms);
+	return;
+}
+
+
+/*
+ * Setup SDIO RX
+ *
+ * Hooks up the IRQ handler and then enables IRQs.
+ */
+int i2400ms_rx_setup(struct i2400ms *i2400ms)
+{
+	int result;
+	struct sdio_func *func = i2400ms->func;
+	struct device *dev = &func->dev;
+
+	d_fnstart(5, dev, "(i2400ms %p)\n", i2400ms);
+	sdio_claim_host(func);
+	result = sdio_claim_irq(func, i2400ms_irq);
+	if (result < 0) {
+		dev_err(dev, "Cannot claim IRQ: %d\n", result);
+		goto error_irq_claim;
+	}
+	result = 0;
+	sdio_writeb(func, 1, I2400MS_INTR_ENABLE_ADDR, &result);
+	if (result < 0) {
+		sdio_release_irq(func);
+		dev_err(dev, "Failed to enable interrupts %d\n", result);
+	}
+error_irq_claim:
+	sdio_release_host(func);
+	d_fnend(5, dev, "(i2400ms %p) = %d\n", i2400ms, result);
+	return result;
+}
+
+
+/*
+ * Tear down SDIO RX
+ *
+ * Disables IRQs in the device and removes the IRQ handler.
+ */
+void i2400ms_rx_release(struct i2400ms *i2400ms)
+{
+	int result;
+	struct sdio_func *func = i2400ms->func;
+	struct device *dev = &func->dev;
+
+	d_fnstart(5, dev, "(i2400ms %p)\n", i2400ms);
+	sdio_claim_host(func);
+	sdio_writeb(func, 0, I2400MS_INTR_ENABLE_ADDR, &result);
+	sdio_release_irq(func);
+	sdio_release_host(func);
+	d_fnend(5, dev, "(i2400ms %p) = %d\n", i2400ms, result);
+}
-- 
1.5.6.5

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