From 072de836f53be56a70cecf70b43ae43b7ce17376 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 11 Dec 2023 10:08:36 +0000
Subject: [PATCH] mk-rootfs.sh
---
kernel/drivers/spi/spi-bcm2835aux.c | 161 +++++++++++++++++++++++++++++++++++++++++------------
1 files changed, 124 insertions(+), 37 deletions(-)
diff --git a/kernel/drivers/spi/spi-bcm2835aux.c b/kernel/drivers/spi/spi-bcm2835aux.c
index 8ea7e31..1a26865 100644
--- a/kernel/drivers/spi/spi-bcm2835aux.c
+++ b/kernel/drivers/spi/spi-bcm2835aux.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for Broadcom BCM2835 auxiliary SPI Controllers
*
@@ -7,20 +8,11 @@
* Based on: spi-bcm2835.c
*
* Copyright (C) 2015 Martin Sperl
- *
- * 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/clk.h>
#include <linux/completion.h>
+#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
@@ -35,6 +27,12 @@
#include <linux/regmap.h>
#include <linux/spi/spi.h>
#include <linux/spinlock.h>
+
+/* define polling limits */
+static unsigned int polling_limit_us = 30;
+module_param(polling_limit_us, uint, 0664);
+MODULE_PARM_DESC(polling_limit_us,
+ "time in us to run a transfer in polling mode - if zero no polling is used\n");
/*
* spi register defines
@@ -88,10 +86,6 @@
#define BCM2835_AUX_SPI_STAT_BUSY 0x00000040
#define BCM2835_AUX_SPI_STAT_BITCOUNT 0x0000003F
-/* timeout values */
-#define BCM2835_AUX_SPI_POLLING_LIMIT_US 30
-#define BCM2835_AUX_SPI_POLLING_JIFFIES 2
-
struct bcm2835aux_spi {
void __iomem *regs;
struct clk *clk;
@@ -102,7 +96,52 @@
int tx_len;
int rx_len;
int pending;
+
+ u64 count_transfer_polling;
+ u64 count_transfer_irq;
+ u64 count_transfer_irq_after_poll;
+
+ struct dentry *debugfs_dir;
};
+
+#if defined(CONFIG_DEBUG_FS)
+static void bcm2835aux_debugfs_create(struct bcm2835aux_spi *bs,
+ const char *dname)
+{
+ char name[64];
+ struct dentry *dir;
+
+ /* get full name */
+ snprintf(name, sizeof(name), "spi-bcm2835aux-%s", dname);
+
+ /* the base directory */
+ dir = debugfs_create_dir(name, NULL);
+ bs->debugfs_dir = dir;
+
+ /* the counters */
+ debugfs_create_u64("count_transfer_polling", 0444, dir,
+ &bs->count_transfer_polling);
+ debugfs_create_u64("count_transfer_irq", 0444, dir,
+ &bs->count_transfer_irq);
+ debugfs_create_u64("count_transfer_irq_after_poll", 0444, dir,
+ &bs->count_transfer_irq_after_poll);
+}
+
+static void bcm2835aux_debugfs_remove(struct bcm2835aux_spi *bs)
+{
+ debugfs_remove_recursive(bs->debugfs_dir);
+ bs->debugfs_dir = NULL;
+}
+#else
+static void bcm2835aux_debugfs_create(struct bcm2835aux_spi *bs,
+ const char *dname)
+{
+}
+
+static void bcm2835aux_debugfs_remove(struct bcm2835aux_spi *bs)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
static inline u32 bcm2835aux_rd(struct bcm2835aux_spi *bs, unsigned reg)
{
@@ -123,15 +162,12 @@
data = bcm2835aux_rd(bs, BCM2835_AUX_SPI_IO);
if (bs->rx_buf) {
switch (count) {
- case 4:
- *bs->rx_buf++ = (data >> 24) & 0xff;
- /* fallthrough */
case 3:
*bs->rx_buf++ = (data >> 16) & 0xff;
- /* fallthrough */
+ fallthrough;
case 2:
*bs->rx_buf++ = (data >> 8) & 0xff;
- /* fallthrough */
+ fallthrough;
case 1:
*bs->rx_buf++ = (data >> 0) & 0xff;
/* fallthrough - no default */
@@ -245,6 +281,9 @@
{
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+ /* update statistics */
+ bs->count_transfer_irq++;
+
/* fill in registers and fifos before enabling interrupts */
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]);
@@ -268,12 +307,15 @@
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
unsigned long timeout;
+ /* update statistics */
+ bs->count_transfer_polling++;
+
/* configure spi */
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]);
- /* set the timeout */
- timeout = jiffies + BCM2835_AUX_SPI_POLLING_JIFFIES;
+ /* set the timeout to at least 2 jiffies */
+ timeout = jiffies + 2 + HZ * polling_limit_us / 1000000;
/* loop until finished the transfer */
while (bs->rx_len) {
@@ -288,6 +330,7 @@
jiffies - timeout,
bs->tx_len, bs->rx_len);
/* forward to interrupt handler */
+ bs->count_transfer_irq_after_poll++;
return __bcm2835aux_spi_transfer_one_irq(master,
spi, tfr);
}
@@ -303,7 +346,7 @@
{
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
unsigned long spi_hz, clk_hz, speed;
- unsigned long spi_used_hz;
+ unsigned long hz_per_byte, byte_limit;
/* calculate the registers to handle
*
@@ -331,7 +374,7 @@
/* set the new speed */
bs->cntl[0] |= speed << BCM2835_AUX_SPI_CNTL0_SPEED_SHIFT;
- spi_used_hz = clk_hz / (2 * (speed + 1));
+ tfr->effective_speed_hz = clk_hz / (2 * (speed + 1));
/* set transmit buffers and length */
bs->tx_buf = tfr->tx_buf;
@@ -347,14 +390,15 @@
* of Hz per byte per polling limit. E.g., we can transfer 1 byte in
* 30 µs per 300,000 Hz of bus clock.
*/
-#define HZ_PER_BYTE ((9 * 1000000) / BCM2835_AUX_SPI_POLLING_LIMIT_US)
+ hz_per_byte = polling_limit_us ? (9 * 1000000) / polling_limit_us : 0;
+ byte_limit = hz_per_byte ? tfr->effective_speed_hz / hz_per_byte : 1;
+
/* run in polling mode for short transfers */
- if (tfr->len < spi_used_hz / HZ_PER_BYTE)
+ if (tfr->len < byte_limit)
return bcm2835aux_spi_transfer_one_poll(master, spi, tfr);
/* run in interrupt mode for all others */
return bcm2835aux_spi_transfer_one_irq(master, spi, tfr);
-#undef HZ_PER_BYTE
}
static int bcm2835aux_spi_prepare_message(struct spi_master *master,
@@ -399,19 +443,60 @@
bcm2835aux_spi_reset_hw(bs);
}
+static int bcm2835aux_spi_setup(struct spi_device *spi)
+{
+ int ret;
+
+ /* sanity check for native cs */
+ if (spi->mode & SPI_NO_CS)
+ return 0;
+ if (gpio_is_valid(spi->cs_gpio)) {
+ /* with gpio-cs set the GPIO to the correct level
+ * and as output (in case the dt has the gpio not configured
+ * as output but native cs)
+ */
+ ret = gpio_direction_output(spi->cs_gpio,
+ (spi->mode & SPI_CS_HIGH) ? 0 : 1);
+ if (ret)
+ dev_err(&spi->dev,
+ "could not set gpio %i as output: %i\n",
+ spi->cs_gpio, ret);
+
+ return ret;
+ }
+
+ /* for dt-backwards compatibility: only support native on CS0
+ * known things not supported with broken native CS:
+ * * multiple chip-selects: cs0-cs2 are all
+ * simultaniously asserted whenever there is a transfer
+ * this even includes SPI_NO_CS
+ * * SPI_CS_HIGH: cs are always asserted low
+ * * cs_change: cs is deasserted after each spi_transfer
+ * * cs_delay_usec: cs is always deasserted one SCK cycle
+ * after the last transfer
+ * probably more...
+ */
+ dev_warn(&spi->dev,
+ "Native CS is not supported - please configure cs-gpio in device-tree\n");
+
+ if (spi->chip_select == 0)
+ return 0;
+
+ dev_warn(&spi->dev, "Native CS is not working for cs > 0\n");
+
+ return -EINVAL;
+}
+
static int bcm2835aux_spi_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct bcm2835aux_spi *bs;
- struct resource *res;
unsigned long clk_hz;
int err;
master = devm_spi_alloc_master(&pdev->dev, sizeof(*bs));
- if (!master) {
- dev_err(&pdev->dev, "spi_alloc_master() failed\n");
+ if (!master)
return -ENOMEM;
- }
platform_set_drvdata(pdev, master);
master->mode_bits = (SPI_CPOL | SPI_CS_HIGH | SPI_NO_CS);
@@ -428,6 +513,7 @@
* a spi_transfer
*/
master->num_chipselect = 1;
+ master->setup = bcm2835aux_spi_setup;
master->transfer_one = bcm2835aux_spi_transfer_one;
master->handle_err = bcm2835aux_spi_handle_err;
master->prepare_message = bcm2835aux_spi_prepare_message;
@@ -437,23 +523,20 @@
bs = spi_master_get_devdata(master);
/* the main area */
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- bs->regs = devm_ioremap_resource(&pdev->dev, res);
+ bs->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(bs->regs))
return PTR_ERR(bs->regs);
bs->clk = devm_clk_get(&pdev->dev, NULL);
- if ((!bs->clk) || (IS_ERR(bs->clk))) {
+ if (IS_ERR(bs->clk)) {
err = PTR_ERR(bs->clk);
dev_err(&pdev->dev, "could not get clk: %d\n", err);
return err;
}
bs->irq = platform_get_irq(pdev, 0);
- if (bs->irq <= 0) {
- dev_err(&pdev->dev, "could not get IRQ: %d\n", bs->irq);
+ if (bs->irq <= 0)
return bs->irq ? bs->irq : -ENODEV;
- }
/* this also enables the HW block */
err = clk_prepare_enable(bs->clk);
@@ -488,6 +571,8 @@
goto out_clk_disable;
}
+ bcm2835aux_debugfs_create(bs, dev_name(&pdev->dev));
+
return 0;
out_clk_disable:
@@ -499,6 +584,8 @@
{
struct spi_master *master = platform_get_drvdata(pdev);
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+
+ bcm2835aux_debugfs_remove(bs);
spi_unregister_master(master);
@@ -528,4 +615,4 @@
MODULE_DESCRIPTION("SPI controller driver for Broadcom BCM2835 aux");
MODULE_AUTHOR("Martin Sperl <kernel@martin.sperl.org>");
-MODULE_LICENSE("GPL v2");
+MODULE_LICENSE("GPL");
--
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