[PATCH v16 08/11] fw_cfg: add DMA register

Marc-André Lureau
2018-02-28T15:06:57Z

Add an optional <dma_off> kernel module (or command line) parameter
using the following syntax:

[qemu_fw_cfg.]ioport=<size>@ [:<ctrl_off>:<data_off>[:<dma_off>]]
or
[qemu_fw_cfg.]mmio=<size>@ [:<ctrl_off>:<data_off>[:<dma_off>]]

and initializes the register address using given or default offset.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Gabriel Somlo <somlo@cmu.edu>
---
drivers/firmware/qemu_fw_cfg.c | 53 ++++++++++++++++++++++++++++++++----------
1 file changed, 41 insertions(+), 12 deletions(-)

diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index 5de6bb406fb6..df028faa2d00 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -10,20 +10,21 @@
* and select subsets of aarch64), a Device Tree node (on arm), or using
* a kernel module (or command line) parameter with the following syntax:
*
- * [qemu_fw_cfg.]ioport=<size>@ [:<ctrl_off>:<data_off>]
+ * [qemu_fw_cfg.]ioport=<size>@ [:<ctrl_off>:<data_off>[:<dma_off>]]
* or
- * [qemu_fw_cfg.]mmio=<size>@ [:<ctrl_off>:<data_off>]
+ * [qemu_fw_cfg.]mmio=<size>@ [:<ctrl_off>:<data_off>[:<dma_off>]]
*
* where:
* <size> := size of ioport or mmio range
* := physical base address of ioport or mmio range
* <ctrl_off> := (optional) offset of control register
* <data_off> := (optional) offset of data register
+ * <dma_off> := (optional) offset of dma register
*
* e.g.:
- * qemu_fw_cfg.ioport=2@0x510:0:1 (the default on x86)
+ * qemu_fw_cfg.ioport=12@0x510:0:1:4 (the default on x86)
* or
- * qemu_fw_cfg.mmio=0xA@0x9020000:8:0 (the default on arm)
+ * qemu_fw_cfg.mmio=16@0x9020000:8:0:16 (the default on arm)
*/

#include <linux/module.h>
@@ -45,6 +46,7 @@ static resource_size_t fw_cfg_p_size;
static void __iomem *fw_cfg_dev_base;
static void __iomem *fw_cfg_reg_ctrl;
static void __iomem *fw_cfg_reg_data;
+static void __iomem *fw_cfg_reg_dma;

/* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */
static DEFINE_MUTEX(fw_cfg_dev_lock);
@@ -104,12 +106,14 @@ static void fw_cfg_io_cleanup(void)
# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64))
# define FW_CFG_CTRL_OFF 0x08
# define FW_CFG_DATA_OFF 0x00
+# define FW_CFG_DMA_OFF 0x10
# elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */
# define FW_CFG_CTRL_OFF 0x00
# define FW_CFG_DATA_OFF 0x02
# elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */
# define FW_CFG_CTRL_OFF 0x00
# define FW_CFG_DATA_OFF 0x01
+# define FW_CFG_DMA_OFF 0x04
# else
# error "QEMU FW_CFG not available on this architecture!"
# endif
@@ -119,7 +123,7 @@ static void fw_cfg_io_cleanup(void)
static int fw_cfg_do_platform_probe(struct platform_device *pdev)
{
char sig[FW_CFG_SIG_SIZE];
- struct resource *range, *ctrl, *data;
+ struct resource *range, *ctrl, *data, *dma;

/* acquire i/o range details */
fw_cfg_is_mmio = false;
@@ -156,6 +160,7 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
/* were custom register offsets provided (e.g. on the command line)? */
ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl");
data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data");
+ dma = platform_get_resource_byname(pdev, IORESOURCE_REG, "dma");
if (ctrl && data) {
fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
fw_cfg_reg_data = fw_cfg_dev_base + data->start;
@@ -165,6 +170,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF;
}

+ if (dma)
+ fw_cfg_reg_dma = fw_cfg_dev_base + dma->start;
+#ifdef FW_CFG_DMA_OFF
+ else
+ fw_cfg_reg_dma = fw_cfg_dev_base + FW_CFG_DMA_OFF;
+#endif
+
/* verify fw_cfg device signature */
if (fw_cfg_read_blob(FW_CFG_SIGNATURE, sig,
0, FW_CFG_SIG_SIZE) < 0 ||
@@ -630,6 +642,7 @@ static struct platform_device *fw_cfg_cmdline_dev;
/* use special scanf/printf modifier for phys_addr_t, resource_size_t */
#define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \
":%" __PHYS_ADDR_PREFIX "i" \
+ ":%" __PHYS_ADDR_PREFIX "i%n" \
":%" __PHYS_ADDR_PREFIX "i%n"

#define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \
@@ -639,12 +652,15 @@ static struct platform_device *fw_cfg_cmdline_dev;
":%" __PHYS_ADDR_PREFIX "u" \
":%" __PHYS_ADDR_PREFIX "u"

+#define PH_ADDR_PR_4_FMT PH_ADDR_PR_3_FMT \
+ ":%" __PHYS_ADDR_PREFIX "u"
+
static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
{
- struct resource res[3] = {};
+ struct resource res[4] = {};
char *str;
phys_addr_t base;
- resource_size_t size, ctrl_off, data_off;
+ resource_size_t size, ctrl_off, data_off, dma_off;
int processed, consumed = 0;

/* only one fw_cfg device can exist system-wide, so if one
@@ -660,19 +676,20 @@ static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
/* consume "<size>" portion of command line argument */
size = memparse(arg, &str);

- /* get "@ [:<ctrl_off>:<data_off>]" chunks */
+ /* get "@ [:<ctrl_off>:<data_off>[:<dma_off>]]" chunks */
processed = sscanf(str, PH_ADDR_SCAN_FMT,
&base, &consumed,
- &ctrl_off, &data_off, &consumed);
+ &ctrl_off, &data_off, &consumed,
+ &dma_off, &consumed);

- /* sscanf() must process precisely 1 or 3 chunks:
+ /* sscanf() must process precisely 1, 3 or 4 chunks:
* is mandatory, optionally followed by <ctrl_off>
- * and <data_off>;
+ * and <data_off>, and <dma_off>;
* there must be no extra characters after the last chunk,
* so str[consumed] must be '\0'.
*/
if (str[consumed] ||
- (processed != 1 && processed != 3))
+ (processed != 1 && processed != 3 && processed != 4))
return -EINVAL;

res[0].start = base;
@@ -689,6 +706,11 @@ static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
res[2].start = data_off;
res[2].flags = IORESOURCE_REG;
}
+ if (processed > 3) {
+ res[3].name = "dma";
+ res[3].start = dma_off;
+ res[3].flags = IORESOURCE_REG;
+ }

/* "processed" happens to nicely match the number of resources
* we need to pass in to this platform device.
@@ -721,6 +743,13 @@ static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
fw_cfg_cmdline_dev->resource[0].start,
fw_cfg_cmdline_dev->resource[1].start,
fw_cfg_cmdline_dev->resource[2].start);
+ case 4:
+ return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_4_FMT,
+ resource_size(&fw_cfg_cmdline_dev->resource[0]),
+ fw_cfg_cmdline_dev->resource[0].start,
+ fw_cfg_cmdline_dev->resource[1].start,
+ fw_cfg_cmdline_dev->resource[2].start,
+ fw_cfg_cmdline_dev->resource[3].start);
}

/* Should never get here */
--
2.16.1.73.g5832b7e9f2