[PATCH 2/6] rtc: rtc-m48t86: add hooks to support driver side memory mapping
Ryan Mallon
rmallon at gmail.com
Mon Apr 1 19:36:43 EDT 2013
On 02/04/13 10:22, Alexander Clouter wrote:
> If platform_data is not defined (as before), then named memory io
> ranges need to be defined ("rtc_index" and "rtc_data"). The driver
> then maps those regions and uses them as the RTC index and data
> addresses.
>
> Does compile with the following warnings, I cannot see the codepath
> affected myself:
> ----
> drivers/rtc/rtc-m48t86.c: In function ‘m48t86_rtc_probe’:
> drivers/rtc/rtc-m48t86.c:180: warning: ‘res_index’ may be used uninitialized in this function
> drivers/rtc/rtc-m48t86.c:180: warning: ‘res_data’ may be used uninitialized in this function
It is caused by the exit paths. If pdev->dev.platform_data is set, the
res_index and res_data are never initialised, but in the error case you
still for rtc_device_register you jump to out_io_data, which will then
dereference res_index/res_data. You need to make the exit paths
conditional on pdev->dev.platform_data (or init res_index/data to NULL
and make the release_mem_regions conditional on that).
~Ryan
> ----
>
> Signed-off-by: Alexander Clouter <alex at digriz.org.uk>
> ---
> drivers/rtc/rtc-m48t86.c | 230 ++++++++++++++++++++++++++++++++++------------
> 1 file changed, 173 insertions(+), 57 deletions(-)
>
> diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c
> index 25e0116..6f99e64 100644
> --- a/drivers/rtc/rtc-m48t86.c
> +++ b/drivers/rtc/rtc-m48t86.c
> @@ -18,6 +18,8 @@
> #include <linux/platform_device.h>
> #include <linux/platform_data/rtc-m48t86.h>
> #include <linux/bcd.h>
> +#include <linux/slab.h>
> +#include <linux/io.h>
>
> #define M48T86_REG_SEC 0x00
> #define M48T86_REG_SECALRM 0x01
> @@ -41,40 +43,71 @@
>
> #define DRV_VERSION "0.1"
>
> +struct m48t86_rtc_private_data {
> + void __iomem *io_index;
> + void __iomem *io_data;
> +
> + struct rtc_device *rtc;
> + struct m48t86_ops *ops;
> +};
> +
> +static void m48t86_rtc_writebyte(struct device *dev,
> + unsigned char value, unsigned long addr)
> +{
> + struct m48t86_rtc_private_data *priv = dev_get_drvdata(dev);
> +
> + if (priv->ops) {
> + priv->ops->writebyte(value, addr);
> + return;
> + }
> +
> + writeb(addr, priv->io_index);
> + writeb(value, priv->io_data);
> +}
> +
> +static unsigned char m48t86_rtc_readbyte(struct device *dev,
> + unsigned long addr)
> +{
> + struct m48t86_rtc_private_data *priv = dev_get_drvdata(dev);
> +
> + if (priv->ops)
> + return priv->ops->readbyte(addr);
> +
> + writeb(addr, priv->io_index);
> + return readb(priv->io_data);
> +}
>
> static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
> {
> unsigned char reg;
> - struct platform_device *pdev = to_platform_device(dev);
> - struct m48t86_ops *ops = pdev->dev.platform_data;
>
> - reg = ops->readbyte(M48T86_REG_B);
> + reg = m48t86_rtc_readbyte(dev, M48T86_REG_B);
>
> if (reg & M48T86_REG_B_DM) {
> /* data (binary) mode */
> - tm->tm_sec = ops->readbyte(M48T86_REG_SEC);
> - tm->tm_min = ops->readbyte(M48T86_REG_MIN);
> - tm->tm_hour = ops->readbyte(M48T86_REG_HOUR) & 0x3F;
> - tm->tm_mday = ops->readbyte(M48T86_REG_DOM);
> + tm->tm_sec = m48t86_rtc_readbyte(dev, M48T86_REG_SEC);
> + tm->tm_min = m48t86_rtc_readbyte(dev, M48T86_REG_MIN);
> + tm->tm_hour = m48t86_rtc_readbyte(dev, M48T86_REG_HOUR) & 0x3F;
> + tm->tm_mday = m48t86_rtc_readbyte(dev, M48T86_REG_DOM);
> /* tm_mon is 0-11 */
> - tm->tm_mon = ops->readbyte(M48T86_REG_MONTH) - 1;
> - tm->tm_year = ops->readbyte(M48T86_REG_YEAR) + 100;
> - tm->tm_wday = ops->readbyte(M48T86_REG_DOW);
> + tm->tm_mon = m48t86_rtc_readbyte(dev, M48T86_REG_MONTH) - 1;
> + tm->tm_year = m48t86_rtc_readbyte(dev, M48T86_REG_YEAR) + 100;
> + tm->tm_wday = m48t86_rtc_readbyte(dev, M48T86_REG_DOW);
> } else {
> /* bcd mode */
> - tm->tm_sec = bcd2bin(ops->readbyte(M48T86_REG_SEC));
> - tm->tm_min = bcd2bin(ops->readbyte(M48T86_REG_MIN));
> - tm->tm_hour = bcd2bin(ops->readbyte(M48T86_REG_HOUR) & 0x3F);
> - tm->tm_mday = bcd2bin(ops->readbyte(M48T86_REG_DOM));
> + tm->tm_sec = bcd2bin(m48t86_rtc_readbyte(dev, M48T86_REG_SEC));
> + tm->tm_min = bcd2bin(m48t86_rtc_readbyte(dev, M48T86_REG_MIN));
> + tm->tm_hour = bcd2bin(m48t86_rtc_readbyte(dev, M48T86_REG_HOUR) & 0x3F);
> + tm->tm_mday = bcd2bin(m48t86_rtc_readbyte(dev, M48T86_REG_DOM));
> /* tm_mon is 0-11 */
> - tm->tm_mon = bcd2bin(ops->readbyte(M48T86_REG_MONTH)) - 1;
> - tm->tm_year = bcd2bin(ops->readbyte(M48T86_REG_YEAR)) + 100;
> - tm->tm_wday = bcd2bin(ops->readbyte(M48T86_REG_DOW));
> + tm->tm_mon = bcd2bin(m48t86_rtc_readbyte(dev, M48T86_REG_MONTH)) - 1;
> + tm->tm_year = bcd2bin(m48t86_rtc_readbyte(dev, M48T86_REG_YEAR)) + 100;
> + tm->tm_wday = bcd2bin(m48t86_rtc_readbyte(dev, M48T86_REG_DOW));
> }
>
> /* correct the hour if the clock is in 12h mode */
> if (!(reg & M48T86_REG_B_H24))
> - if (ops->readbyte(M48T86_REG_HOUR) & 0x80)
> + if (m48t86_rtc_readbyte(dev, M48T86_REG_HOUR) & 0x80)
> tm->tm_hour += 12;
>
> return rtc_valid_tm(tm);
> @@ -83,38 +116,36 @@ static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
> static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
> {
> unsigned char reg;
> - struct platform_device *pdev = to_platform_device(dev);
> - struct m48t86_ops *ops = pdev->dev.platform_data;
>
> - reg = ops->readbyte(M48T86_REG_B);
> + reg = m48t86_rtc_readbyte(dev, M48T86_REG_B);
>
> /* update flag and 24h mode */
> reg |= M48T86_REG_B_SET | M48T86_REG_B_H24;
> - ops->writebyte(reg, M48T86_REG_B);
> + m48t86_rtc_writebyte(dev, reg, M48T86_REG_B);
>
> if (reg & M48T86_REG_B_DM) {
> /* data (binary) mode */
> - ops->writebyte(tm->tm_sec, M48T86_REG_SEC);
> - ops->writebyte(tm->tm_min, M48T86_REG_MIN);
> - ops->writebyte(tm->tm_hour, M48T86_REG_HOUR);
> - ops->writebyte(tm->tm_mday, M48T86_REG_DOM);
> - ops->writebyte(tm->tm_mon + 1, M48T86_REG_MONTH);
> - ops->writebyte(tm->tm_year % 100, M48T86_REG_YEAR);
> - ops->writebyte(tm->tm_wday, M48T86_REG_DOW);
> + m48t86_rtc_writebyte(dev, tm->tm_sec, M48T86_REG_SEC);
> + m48t86_rtc_writebyte(dev, tm->tm_min, M48T86_REG_MIN);
> + m48t86_rtc_writebyte(dev, tm->tm_hour, M48T86_REG_HOUR);
> + m48t86_rtc_writebyte(dev, tm->tm_mday, M48T86_REG_DOM);
> + m48t86_rtc_writebyte(dev, tm->tm_mon + 1, M48T86_REG_MONTH);
> + m48t86_rtc_writebyte(dev, tm->tm_year % 100, M48T86_REG_YEAR);
> + m48t86_rtc_writebyte(dev, tm->tm_wday, M48T86_REG_DOW);
> } else {
> /* bcd mode */
> - ops->writebyte(bin2bcd(tm->tm_sec), M48T86_REG_SEC);
> - ops->writebyte(bin2bcd(tm->tm_min), M48T86_REG_MIN);
> - ops->writebyte(bin2bcd(tm->tm_hour), M48T86_REG_HOUR);
> - ops->writebyte(bin2bcd(tm->tm_mday), M48T86_REG_DOM);
> - ops->writebyte(bin2bcd(tm->tm_mon + 1), M48T86_REG_MONTH);
> - ops->writebyte(bin2bcd(tm->tm_year % 100), M48T86_REG_YEAR);
> - ops->writebyte(bin2bcd(tm->tm_wday), M48T86_REG_DOW);
> + m48t86_rtc_writebyte(dev, bin2bcd(tm->tm_sec), M48T86_REG_SEC);
> + m48t86_rtc_writebyte(dev, bin2bcd(tm->tm_min), M48T86_REG_MIN);
> + m48t86_rtc_writebyte(dev, bin2bcd(tm->tm_hour), M48T86_REG_HOUR);
> + m48t86_rtc_writebyte(dev, bin2bcd(tm->tm_mday), M48T86_REG_DOM);
> + m48t86_rtc_writebyte(dev, bin2bcd(tm->tm_mon + 1), M48T86_REG_MONTH);
> + m48t86_rtc_writebyte(dev, bin2bcd(tm->tm_year % 100), M48T86_REG_YEAR);
> + m48t86_rtc_writebyte(dev, bin2bcd(tm->tm_wday), M48T86_REG_DOW);
> }
>
> /* update ended */
> reg &= ~M48T86_REG_B_SET;
> - ops->writebyte(reg, M48T86_REG_B);
> + m48t86_rtc_writebyte(dev, reg, M48T86_REG_B);
>
> return 0;
> }
> @@ -122,15 +153,13 @@ static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
> static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq)
> {
> unsigned char reg;
> - struct platform_device *pdev = to_platform_device(dev);
> - struct m48t86_ops *ops = pdev->dev.platform_data;
>
> - reg = ops->readbyte(M48T86_REG_B);
> + reg = m48t86_rtc_readbyte(dev, M48T86_REG_B);
>
> seq_printf(seq, "mode\t\t: %s\n",
> (reg & M48T86_REG_B_DM) ? "binary" : "bcd");
>
> - reg = ops->readbyte(M48T86_REG_D);
> + reg = m48t86_rtc_readbyte(dev, M48T86_REG_D);
>
> seq_printf(seq, "battery\t\t: %s\n",
> (reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
> @@ -144,34 +173,121 @@ static const struct rtc_class_ops m48t86_rtc_ops = {
> .proc = m48t86_rtc_proc,
> };
>
> -static int m48t86_rtc_probe(struct platform_device *dev)
> +static int m48t86_rtc_probe(struct platform_device *pdev)
> {
> unsigned char reg;
> - struct m48t86_ops *ops = dev->dev.platform_data;
> - struct rtc_device *rtc = rtc_device_register("m48t86",
> - &dev->dev, &m48t86_rtc_ops, THIS_MODULE);
> -
> - if (IS_ERR(rtc))
> - return PTR_ERR(rtc);
> -
> - platform_set_drvdata(dev, rtc);
> + int err;
> + struct resource *res_index, *res_data;
> + struct m48t86_rtc_private_data *priv;
> +
> + /* Allocate memory for the device structure (and zero it) */
> + priv = kzalloc(sizeof(struct m48t86_rtc_private_data), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, priv);
> +
> + if (!pdev->dev.platform_data) {
> + res_index = platform_get_resource_byname(
> + pdev, IORESOURCE_MEM, "rtc_index");
> + if (!res_index) {
> + err = -ENXIO;
> + goto out_free;
> + }
> +
> + res_data = platform_get_resource_byname(
> + pdev, IORESOURCE_MEM, "rtc_data");
> + if (!res_data) {
> + err = -ENXIO;
> + goto out_free;
> + }
> +
> + if (!request_mem_region(res_index->start,
> + resource_size(res_index),
> + dev_name(&pdev->dev))) {
> + err = -EBUSY;
> + goto out_free;
> + }
> +
> + if (!request_mem_region(res_data->start,
> + resource_size(res_data),
> + dev_name(&pdev->dev))) {
> + err = -EBUSY;
> + goto out_release_index;
> + }
> +
> + priv->io_index = ioremap(res_index->start,
> + resource_size(res_index));
> + if (!priv->io_index) {
> + err = -EIO;
> + goto out_release_data;
> + }
> +
> + priv->io_data = ioremap(res_data->start,
> + resource_size(res_data));
> + if (!priv->io_data) {
> + err = -EIO;
> + goto out_io_index;
> + }
> + } else
> + priv->ops = pdev->dev.platform_data;
> +
> + priv->rtc = rtc_device_register("m48t86",
> + &pdev->dev, &m48t86_rtc_ops, THIS_MODULE);
> + if (IS_ERR(priv->rtc)) {
> + err = PTR_ERR(priv->rtc);
> + if (!pdev->dev.platform_data)
> + goto out_io_data;
> + else
> + goto out_free;
> + }
>
> /* read battery status */
> - reg = ops->readbyte(M48T86_REG_D);
> - dev_info(&dev->dev, "battery %s\n",
> + reg = m48t86_rtc_readbyte(&pdev->dev, M48T86_REG_D);
> + dev_info(&pdev->dev, "battery %s\n",
> (reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
>
> return 0;
> +
> +out_io_data:
> + iounmap(priv->io_data);
> +out_io_index:
> + iounmap(priv->io_index);
> +out_release_data:
> + release_mem_region(res_data->start, resource_size(res_data));
> +out_release_index:
> + release_mem_region(res_index->start, resource_size(res_index));
> +out_free:
> + platform_set_drvdata(pdev, NULL);
> + kfree(priv);
> + return err;
> }
>
> -static int m48t86_rtc_remove(struct platform_device *dev)
> +static int m48t86_rtc_remove(struct platform_device *pdev)
> {
> - struct rtc_device *rtc = platform_get_drvdata(dev);
> + struct resource *res;
> + struct m48t86_rtc_private_data *priv = platform_get_drvdata(pdev);
> +
> + if (priv->rtc)
> + rtc_device_unregister(priv->rtc);
> +
> + if (priv->io_data) {
> + iounmap(priv->io_data);
> + res = platform_get_resource_byname(
> + pdev, IORESOURCE_MEM, "rtc_data");
> + release_mem_region(res->start, resource_size(res));
> + }
> +
> + if (priv->io_index) {
> + iounmap(priv->io_index);
> + res = platform_get_resource_byname(
> + pdev, IORESOURCE_MEM, "rtc_index");
> + release_mem_region(res->start, resource_size(res));
> + }
>
> - if (rtc)
> - rtc_device_unregister(rtc);
> + platform_set_drvdata(pdev, NULL);
>
> - platform_set_drvdata(dev, NULL);
> + kfree(priv);
>
> return 0;
> }
>
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