On 06/15/2017 01:58 AM, Jiahau Chang wrote:
+void usb_asmedia_modifyflowcontrol(struct pci_dev *pdev)
+{
+ unsigned char value;
+ unsigned long wait_time_count;
+
+ /*check device can accept command*/
+ wait_time_count = 1000;
+ while (wait_time_count) {
+ pci_read_config_byte(pdev, ASMT_CONTROL_REG, &value);
+ if (value == 0xff) {
+ dev_dbg(&pdev->dev, "%s: check_ready ERROR", __func__);
+ goto err_exit;
+ }
+ if ((value & ASMT_CONTROL_WRITE_BIT) == 0)
+ break;
+ wait_time_count--;
+ usleep(50);
+ }
+ if (wait_time_count == 0) {
+ dev_dbg(&pdev->dev, "%s: check_write_ready timeout", __func__);
+ goto err_exit;
+ }
+ /* send command and address to device */
+ pci_write_config_dword(pdev, ASMT_DATA_WRITE0_REG, ASMT_WRITEREG_CMD);
+ pci_write_config_dword(pdev, ASMT_DATA_WRITE1_REG, ASMT_FLOWCTL_ADDR);
+ pci_write_config_byte(pdev, ASMT_CONTROL_REG, ASMT_CONTROL_WRITE_BIT);
+ wait_time_count = 1000;
+ /* wait device receive the data */
+ while (wait_time_count) {
+ pci_read_config_byte(pdev, ASMT_CONTROL_REG, &value);
+ if (value == 0xff) {
+ dev_dbg(&pdev->dev, "%s: wait_ready ERROR", __func__);
+ goto err_exit;
+ }
+ if ((value & ASMT_CONTROL_WRITE_BIT) == 0)
+ break;
+ wait_time_count--;
+ usleep(50);
+ }
+ if (wait_time_count == 0) {
+ dev_dbg(&pdev->dev, "%s: wait_write_ready timeout", __func__);
+ goto err_exit;
+ }
+ /* send data to device */
+ pci_write_config_dword(pdev, ASMT_DATA_WRITE0_REG, ASMT_FLOWCTL_DATA);
+ pci_write_config_dword(pdev, ASMT_DATA_WRITE1_REG, ASMT_PSEUDO_DATA);
+ pci_write_config_byte(pdev, ASMT_CONTROL_REG, ASMT_CONTROL_WRITE_BIT);
+err_exit:
+ return;
+}
As others have pointed out, this flow is not very clear to the first-
time reader. Maybe something like this (WARNING untested):
static int usb_asmedia_wait_write(struct pci_dev *pdev, unsigned long
wait_usec)
{
unsigned long wait_count;
unsigned char value;
for (wait_count = wait_usec / 50; wait_count > 0; --wait_count) {
pci_read_config_byte(pdev, ASMT_CONTROL_REG, &value);
if (value == 0xff) {
dev_dbg(&pdev->dev, "%s: check_ready ERROR", __func__);
return -1;
}
if ((value & ASMT_CONTROL_WRITE_BIT) == 0)
return 0;
}
dev_dbg(&pdev->dev, "%s: check_write_ready timeout", __func__);
return -1;
}
void usb_asmedia_modifyflowcontrol(struct pci_dev *dev)
{
if (usb_asmedia_wait_write(pdev, 50000) != 0)
goto err_exit;
/* send command and address to device */
pci_write_config_dword(pdev, ASMT_DATA_WRITE0_REG, ASMT_WRITEREG_CMD);
pci_write_config_dword(pdev, ASMT_DATA_WRITE1_REG, ASMT_FLOWCTL_ADDR);
pci_write_config_byte(pdev, ASMT_CONTROL_REG, ASMT_CONTROL_WRITE_BIT);
if (usb_asmedia_wait_write(pdev, 50000) != 0)
goto err_exit;
/* send data to device */
pci_write_config_dword(pdev, ASMT_DATA_WRITE0_REG, ASMT_FLOWCTL_DATA);
pci_write_config_dword(pdev, ASMT_DATA_WRITE1_REG, ASMT_PSEUDO_DATA);
pci_write_config_byte(pdev, ASMT_CONTROL_REG, ASMT_CONTROL_WRITE_BIT);
err_exit:
return;
}
--
========================================================================
Ian Pilcher [email protected]
-------- "I grew up before Mark Zuckerberg invented friendship" --------
========================================================================
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