@@ -33,6 +33,7 @@
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/ioport.h>
+#include <linux/dma-mapping.h>
MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
@@ -43,12 +44,25 @@ MODULE_LICENSE("GPL");
#define FW_CFG_ID 0x01
#define FW_CFG_FILE_DIR 0x19
+#define FW_CFG_VERSION_DMA 0x02
+#define FW_CFG_DMA_CTL_ERROR 0x01
+#define FW_CFG_DMA_CTL_READ 0x02
+#define FW_CFG_DMA_CTL_SKIP 0x04
+#define FW_CFG_DMA_CTL_SELECT 0x08
+#define FW_CFG_DMA_CTL_WRITE 0x10
+
/* size in bytes of fw_cfg signature */
#define FW_CFG_SIG_SIZE 4
/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
#define FW_CFG_MAX_FILE_PATH 56
+/* platform device for dma mapping */
+static struct device *dev;
+
+/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
+static u32 fw_cfg_rev;
+
/* fw_cfg file directory entry type */
struct fw_cfg_file {
u32 size;
@@ -57,6 +71,12 @@ struct fw_cfg_file {
char name[FW_CFG_MAX_FILE_PATH];
};
+struct fw_cfg_dma {
+ u32 control;
+ u32 length;
+ u64 address;
+} __packed;
+
/* fw_cfg device i/o register addresses */
static bool fw_cfg_is_mmio;
static phys_addr_t fw_cfg_p_base;
@@ -75,12 +95,73 @@ static inline u16 fw_cfg_sel_endianness(u16 key)
return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
}
+static inline bool fw_cfg_dma_enabled(void)
+{
+ return fw_cfg_rev & FW_CFG_VERSION_DMA && fw_cfg_reg_dma;
+}
+
+static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control)
+{
+ dma_addr_t dma_addr = 0;
+ struct fw_cfg_dma *d;
+ dma_addr_t dma;
+ ssize_t ret = length;
+ enum dma_data_direction dir =
+ (control & FW_CFG_DMA_CTL_READ ? DMA_FROM_DEVICE : 0);
+
+ if (address && length) {
+ dma_addr = dma_map_single(dev, address, length, dir);
+ if (dma_mapping_error(NULL, dma_addr)) {
+ WARN(1, "%s: failed to map address\n", __func__);
+ return -EFAULT;
+ }
+ }
+
+ d = kmalloc(sizeof(*d), GFP_KERNEL | GFP_DMA);
+ if (!d) {
+ ret = -ENOMEM;
+ goto end;
+ }
+
+ dma = dma_map_single(dev, d, sizeof(*d), DMA_BIDIRECTIONAL);
+ if (dma_mapping_error(NULL, dma)) {
+ WARN(1, "%s: failed to map fw_cfg_dma\n", __func__);
+ ret = -EFAULT;
+ goto end;
+ }
+
+ *d = (struct fw_cfg_dma) {
+ .address = cpu_to_be64(dma_addr),
+ .length = cpu_to_be32(length),
+ .control = cpu_to_be32(control)
+ };
+
+ iowrite32be((u64)dma >> 32, fw_cfg_reg_dma);
+ iowrite32be(dma, fw_cfg_reg_dma + 4);
+ while (be32_to_cpu(d->control) & ~FW_CFG_DMA_CTL_ERROR)
+ yield(); /* FIXME: wait_event? */
+
+ if (be32_to_cpu(d->control) & FW_CFG_DMA_CTL_ERROR)
+ ret = -EIO;
+
+ dma_unmap_single(dev, dma, sizeof(*d), DMA_BIDIRECTIONAL);
+
+end:
+ kfree(d);
+ if (dma_addr)
+ dma_unmap_single(dev, dma_addr, length, dir);
+
+ return ret;
+}
+
/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
-static inline void fw_cfg_read_blob(u16 key,
- void *buf, loff_t pos, size_t count)
+static ssize_t fw_cfg_read_blob(u16 key,
+ void *buf, loff_t pos, size_t count,
+ bool dma)
{
u32 glk = -1U;
acpi_status status;
+ ssize_t ret = count;
/* If we have ACPI, ensure mutual exclusion against any potential
* device access by the firmware, e.g. via AML methods:
@@ -90,17 +171,36 @@ static inline void fw_cfg_read_blob(u16 key,
/* Should never get here */
WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n");
memset(buf, 0, count);
- return;
+ return -EBUSY;
}
mutex_lock(&fw_cfg_dev_lock);
- iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
- while (pos-- > 0)
- ioread8(fw_cfg_reg_data);
- ioread8_rep(fw_cfg_reg_data, buf, count);
+ if (dma && fw_cfg_dma_enabled()) {
+ if (pos == 0) {
+ ret = fw_cfg_dma_transfer(buf, count, key << 16
+ | FW_CFG_DMA_CTL_SELECT
+ | FW_CFG_DMA_CTL_READ);
+ } else {
+ iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
+ ret = fw_cfg_dma_transfer(0, pos, FW_CFG_DMA_CTL_SKIP);
+ if (ret < 0)
+ goto end;
+ ret = fw_cfg_dma_transfer(buf, count,
+ FW_CFG_DMA_CTL_READ);
+ }
+ } else {
+ iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
+ while (pos-- > 0)
+ ioread8(fw_cfg_reg_data);
+ ioread8_rep(fw_cfg_reg_data, buf, count);
+ }
+
+end:
mutex_unlock(&fw_cfg_dev_lock);
acpi_release_global_lock(glk);
+
+ return ret;
}
/* clean up fw_cfg device i/o */
@@ -192,7 +292,7 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
#endif
/* verify fw_cfg device signature */
- fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE);
+ fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE, false);
if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
fw_cfg_io_cleanup();
return -ENODEV;
@@ -201,9 +301,6 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
return 0;
}
-/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
-static u32 fw_cfg_rev;
-
static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
{
return sprintf(buf, "%u\n", fw_cfg_rev);
@@ -351,8 +448,7 @@ static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
if (count > entry->f.size - pos)
count = entry->f.size - pos;
- fw_cfg_read_blob(entry->f.select, buf, pos, count);
- return count;
+ return fw_cfg_read_blob(entry->f.select, buf, pos, count, true);
}
static struct bin_attribute fw_cfg_sysfs_attr_raw = {
@@ -505,7 +601,7 @@ static int fw_cfg_register_dir_entries(void)
struct fw_cfg_file *dir;
size_t dir_size;
- fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count));
+ fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count), false);
count = be32_to_cpu(count);
dir_size = count * sizeof(struct fw_cfg_file);
@@ -513,7 +609,7 @@ static int fw_cfg_register_dir_entries(void)
if (!dir)
return -ENOMEM;
- fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size);
+ fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size, true);
for (i = 0; i < count; i++) {
dir[i].size = be32_to_cpu(dir[i].size);
@@ -544,9 +640,10 @@ static int fw_cfg_sysfs_probe(struct platform_device *pdev)
* one fw_cfg device exist system-wide, so if one was already found
* earlier, we might as well stop here.
*/
- if (fw_cfg_sel_ko)
+ if (dev)
return -EBUSY;
+ dev = &pdev->dev;
/* create by_key and by_name subdirs of /sys/firmware/qemu_fw_cfg/ */
err = -ENOMEM;
fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko);
@@ -562,7 +659,7 @@ static int fw_cfg_sysfs_probe(struct platform_device *pdev)
goto err_probe;
/* get revision number, add matching top-level attribute */
- fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev));
+ fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev), false);
fw_cfg_rev = le32_to_cpu(fw_cfg_rev);
err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
if (err)
@@ -587,6 +684,7 @@ static int fw_cfg_sysfs_probe(struct platform_device *pdev)
err_name:
fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
err_sel:
+ dev = NULL;
return err;
}