serial: amba-pl011: make platform driver generic

make sbsa uart platform driver more generic so that platform driver code can be reused by ZTE uart platform driver.

Signed-off-by Jun Nie <[email protected]>

---
 drivers/tty/serial/amba-pl011.c | 57 +++++++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 19 deletions(-)

drivers/tty/serial/amba-pl011.c +38 -20

index 7c198e0..2d1917e 100644
@@ -73,6 +73,9 @@
 #define UART_DR_ERROR          (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE)
 #define UART_DUMMY_DR_RX       (1 << 16)
 
+static const struct uart_ops amba_pl011_pops;
+static const struct uart_ops sbsa_uart_pops;
+
 static u16 pl011_std_offsets[REG_ARRAY_SIZE] = {
        [REG_DR] = UART01x_DR,
        [REG_FR] = UART01x_FR,

@@ -92,6 +95,7 @@ static u16 pl011_std_offsets[REG_ARRAY_SIZE] = {
 /* There is by now at least one vendor with differing details, so handle it */
 struct vendor_data {
        const u16               *reg_offset;
+       const struct uart_ops   *uart_pops;
        unsigned int            ifls;
        bool                    access_32b;
        bool                    oversampling;

@@ -119,13 +123,20 @@ static struct vendor_data vendor_arm = {
        .get_fifosize           = get_fifosize_arm,
 };
 
+static unsigned int get_fifosize_sbsa(struct amba_device *dev)
+{
+       return 32;
+}
+
 static struct vendor_data vendor_sbsa = {
        .reg_offset             = pl011_std_offsets,
+       .uart_pops              = &sbsa_uart_pops,
        .oversampling           = false,
        .dma_threshold          = false,
        .cts_event_workaround   = false,
        .always_enabled         = true,
        .fixed_options          = true,
+       .get_fifosize           = get_fifosize_sbsa,
 };
 
 static u16 pl011_st_offsets[REG_ARRAY_SIZE] = {

@@ -189,6 +200,7 @@ static const u16 pl011_zte_offsets[REG_ARRAY_SIZE] = {
 
 static struct vendor_data vendor_zte __maybe_unused = {
        .reg_offset             = pl011_zte_offsets,
+       .uart_pops              = &amba_pl011_pops,
        .access_32b             = true,
        .ifls                   = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
        .get_fifosize           = get_fifosize_arm,

@@ -2086,7 +2098,7 @@ static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser)
        return ret;
 }
 
-static struct uart_ops amba_pl011_pops = {
+static const struct uart_ops amba_pl011_pops = {
        .tx_empty       = pl011_tx_empty,
        .set_mctrl      = pl011_set_mctrl,
        .get_mctrl      = pl011_get_mctrl,

@@ -2521,10 +2533,12 @@ static int pl011_resume(struct device *dev)
 #endif
 
 static SIMPLE_DEV_PM_OPS(pl011_dev_pm_ops, pl011_suspend, pl011_resume);
+static const struct of_device_id pl011_uart_plat_of_match[];
 
-static int sbsa_uart_probe(struct platform_device *pdev)
+static int pl011_uart_plat_probe(struct platform_device *pdev)
 {
        struct uart_amba_port *uap;
+       struct vendor_data *vendor;
        struct resource *r;
        int portnr, ret;
        int baudrate;

@@ -2535,11 +2549,15 @@ static int sbsa_uart_probe(struct platform_device *pdev)
         */
        if (pdev->dev.of_node) {
                struct device_node *np = pdev->dev.of_node;
+               const struct of_device_id *of_id =
+                       of_match_device(pl011_uart_plat_of_match, &pdev->dev);
 
                ret = of_property_read_u32(np, "current-speed", &baudrate);
                if (ret)
                        return ret;
+               vendor = (struct vendor_data *)of_id->data;
        } else {
+               vendor = &vendor_sbsa;
                baudrate = 115200;
        }
 

@@ -2552,15 +2570,15 @@ static int sbsa_uart_probe(struct platform_device *pdev)
        if (!uap)
                return -ENOMEM;
 
-       uap->reg_offset = vendor_sbsa.reg_offset;
-       uap->vendor     = &vendor_sbsa;
-       uap->fifosize   = 32;
-       uap->port.iotype = vendor_sbsa.access_32b ? UPIO_MEM32 : UPIO_MEM;
+       uap->vendor     = vendor;
+       uap->reg_offset = vendor->reg_offset;
+       uap->fifosize   = vendor->get_fifosize(NULL);
+       uap->port.iotype = vendor->access_32b ? UPIO_MEM32 : UPIO_MEM;
        uap->port.irq   = platform_get_irq(pdev, 0);
-       uap->port.ops   = &sbsa_uart_pops;
+       uap->port.ops   = vendor->uart_pops;
        uap->fixed_baud = baudrate;
 
-       snprintf(uap->type, sizeof(uap->type), "SBSA");
+       snprintf(uap->type, sizeof(uap->type), "PL011 plat");
 
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 

@@ -2573,7 +2591,7 @@ static int sbsa_uart_probe(struct platform_device *pdev)
        return pl011_register_port(uap);
 }
 
-static int sbsa_uart_remove(struct platform_device *pdev)
+static int pl011_uart_plat_remove(struct platform_device *pdev)
 {
        struct uart_amba_port *uap = platform_get_drvdata(pdev);
 

@@ -2582,11 +2600,12 @@ static int sbsa_uart_remove(struct platform_device *pdev)
        return 0;
 }
 
-static const struct of_device_id sbsa_uart_of_match[] = {
-       { .compatible = "arm,sbsa-uart", },
+static const struct of_device_id pl011_uart_plat_of_match[] = {
+       { .compatible = "arm,sbsa-uart", .data = &vendor_sbsa },
+       { .compatible = "zte,zx296702-uart", .data = &vendor_zte },
        {},
 };
-MODULE_DEVICE_TABLE(of, sbsa_uart_of_match);
+MODULE_DEVICE_TABLE(of, pl011_uart_plat_of_match);
 
 static const struct acpi_device_id sbsa_uart_acpi_match[] = {
        { "ARMH0011", 0 },

@@ -2594,12 +2613,12 @@ static const struct acpi_device_id sbsa_uart_acpi_match[] = {
 };
 MODULE_DEVICE_TABLE(acpi, sbsa_uart_acpi_match);
 
-static struct platform_driver arm_sbsa_uart_platform_driver = {
-       .probe          = sbsa_uart_probe,
-       .remove         = sbsa_uart_remove,
+static struct platform_driver pl011_uart_platform_driver = {
+       .probe          = pl011_uart_plat_probe,
+       .remove         = pl011_uart_plat_remove,
        .driver = {
-               .name   = "sbsa-uart",
-               .of_match_table = of_match_ptr(sbsa_uart_of_match),
+               .name   = "uart-pl011-plat",
+               .of_match_table = of_match_ptr(pl011_uart_plat_of_match),
                .acpi_match_table = ACPI_PTR(sbsa_uart_acpi_match),
        },
 };

@@ -2634,14 +2653,14 @@ static int __init pl011_init(void)
 {
        printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");
 
-       if (platform_driver_register(&arm_sbsa_uart_platform_driver))
+       if (platform_driver_register(&pl011_uart_platform_driver))
                pr_warn("could not register SBSA UART platform driver\n");
        return amba_driver_register(&pl011_driver);
 }
 
 static void __exit pl011_exit(void)
 {
-       platform_driver_unregister(&arm_sbsa_uart_platform_driver);
+       platform_driver_unregister(&pl011_uart_platform_driver);
        amba_driver_unregister(&pl011_driver);
 }
 
--

1.9.1

Quoted 6 lines · Jun Nie

drivers/tty/serial/amba-pl011.c +0 -0

@@ -2570,9 +2608,17 @@ static int pl011_uart_plat_probe(struct
 platform_device *pdev)
        if (!uap)
                return -ENOMEM;
 

drivers/tty/serial/amba-pl011.c static int pl011_uart_plat_probe(struct platform_device *pdev) · line 2614

Quoted 4 lines

drivers/tty/serial/amba-pl011.c +4 -0

+       uap->clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(uap->clk))
+               return PTR_ERR(uap->clk);
+

I don't this is supposed to be part of your patch, and it breaks my ACPI platform anyway. Where did it come from?

--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation collaborative project.

2016-03-22 4:39 GMT+08:00 Timur Tabi <[email protected]>:

Quoted 7 lines

Quoted 6 lines · Jun Nie

drivers/tty/serial/amba-pl011.c +0 -0

@@ -2570,9 +2608,17 @@ static int pl011_uart_plat_probe(struct
 platform_device *pdev)
         if (!uap)
                 return -ENOMEM;
 

Quoted 9 lines

drivers/tty/serial/amba-pl011.c static int pl011_uart_plat_probe(struct platform_device *pdev) · line 2614

Quoted 4 lines

drivers/tty/serial/amba-pl011.c +4 -0

+       uap->clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(uap->clk))
+               return PTR_ERR(uap->clk);
+

I don't this is supposed to be part of your patch, and it breaks my ACPI platform anyway. Where did it come from?

Is it OK to move to device tree part, I mean if (pdev->dev.of_node) clause? It is part of my patch, I am not aware ACPI requirement on this.

Quoted 21 lines · Jun Nie

2016-03-22 4:39 GMT+08:00 Timur Tabi <[email protected]>:

Quoted 9 lines

Quoted 7 lines · Jun Nie

drivers/tty/serial/amba-pl011.c +0 -0

@@ -2570,9 +2608,17 @@ static int pl011_uart_plat_probe(struct
 platform_device *pdev)
         if (!uap)
                 return -ENOMEM;
 

Quoted 10 lines

drivers/tty/serial/amba-pl011.c static int pl011_uart_plat_probe(struct platform_device *pdev) · line 2614

Quoted 4 lines

drivers/tty/serial/amba-pl011.c +4 -0

+       uap->clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(uap->clk))
+               return PTR_ERR(uap->clk);
+

I don't this is supposed to be part of your patch, and it breaks my ACPI platform anyway. Where did it come from?

Quoted 3 lines

Is it OK to move to device tree part, I mean if (pdev->dev.of_node) clause? It is part of my patch, I am not aware ACPI requirement on this.

But this is not restricted to the ZTE platform. Your patch says, "compete support to ZTE uart" (maybe you should reword that to "add support for ZTE UARTs"). However, this change affects ALL platforms. If you move it to the device tree part, it will affect ALL device tree platforms. That's not "adding ZTE support".

--
Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation.

That's a fair comment. I suppose all platform need to enable clock for the device. For device tree case, we need these code for clock enabling.

For ACPI case, it may be handled automatically. If you agree my opinion, I will move these lines to patch 1. Please correct me if I am wrong.

Quoted 4 lines · Jun Nie

That's a fair comment. I suppose all platform need to enable clock for the device. For device tree case, we need these code for clock enabling.

But why do you need to enable the clock? The pl011 driver works fine for every platform without your patch. If the ZTE platform needs to call clk_get() in order to work, than that is something different about your platform.

Quoted 4 lines

For ACPI case, it may be handled automatically. If you agree my opinion, I will move these lines to patch 1. Please correct me if I am wrong.

I think you need to create a separate patch that adds that call, and make sure it's tested by other platforms before it gets accepted.

--
Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation.

2016-03-22 10:06 GMT+08:00 Timur Tabi <[email protected]>:

Quoted 11 lines

Quoted 4 lines · Jun Nie

That's a fair comment. I suppose all platform need to enable clock for the device. For device tree case, we need these code for clock enabling.

But why do you need to enable the clock? The pl011 driver works fine for every platform without your patch. If the ZTE platform needs to call clk_get() in order to work, than that is something different about your platform.

ARM/ST pl011 is amba device and use pl011_probe() for initialization, which call these clock enabling code for every device. You introduced platform device driver entry for pl011 and only sbsa use platform device probe method currently. I am trying to reuse this probe function, so need to add clock enabling code in this function.

If you did not find any issue in sbsa device tree case, I guess the clock is always enabled. For mobile platform, clock is auto gated for power saving in most of cases.

Quoted 6 lines

Quoted 4 lines

For ACPI case, it may be handled automatically. If you agree my opinion, I will move these lines to patch 1. Please correct me if I am wrong.

Quoted 2 lines

I think you need to create a separate patch that adds that call, and make sure it's tested by other platforms before it gets accepted.

These code only impact sbsa device as only sbsa device is initialized via platform driver entry. So only your flavor is need for testing the code. Thanks! :-)

Quoted 29 lines

2016-03-22 10:06 GMT+08:00 Timur Tabi <[email protected]>:

Quoted 11 lines

Quoted 4 lines · Jun Nie

That's a fair comment. I suppose all platform need to enable clock for the device. For device tree case, we need these code for clock enabling.

But why do you need to enable the clock? The pl011 driver works fine for every platform without your patch. If the ZTE platform needs to call clk_get() in order to work, than that is something different about your platform.

ARM/ST pl011 is amba device and use pl011_probe() for initialization, which call these clock enabling code for every device. You introduced platform device driver entry for pl011 and only sbsa use platform device probe method currently. I am trying to reuse this probe function, so need to add clock enabling code in this function.

If you did not find any issue in sbsa device tree case, I guess the clock is always enabled. For mobile platform, clock is auto gated for power saving in most of cases.

Quoted 6 lines

Quoted 4 lines

For ACPI case, it may be handled automatically. If you agree my opinion, I will move these lines to patch 1. Please correct me if I am wrong.

Quoted 7 lines

Quoted 2 lines

I think you need to create a separate patch that adds that call, and make sure it's tested by other platforms before it gets accepted.

These code only impact sbsa device as only sbsa device is initialized via platform driver entry. So only your flavor is need for testing the code. Thanks! :-)

In SBSA mode the UART clock is always enabled by the firmware and there are no baud rate registers so we don't need to know the value of the clock. In ACPI there is no method to represent the clock. So if you add lines to unconditionally require a clock you will break SBSA mode in ACPI.

Graeme

2016-03-22 16:20 GMT+08:00 G Gregory <[email protected]>:

Quoted 43 lines · Jun Nie

Quoted 29 lines

2016-03-22 10:06 GMT+08:00 Timur Tabi <[email protected]>:

Quoted 11 lines

Quoted 4 lines · Jun Nie

That's a fair comment. I suppose all platform need to enable clock for the device. For device tree case, we need these code for clock enabling.

But why do you need to enable the clock? The pl011 driver works fine for every platform without your patch. If the ZTE platform needs to call clk_get() in order to work, than that is something different about your platform.

ARM/ST pl011 is amba device and use pl011_probe() for initialization, which call these clock enabling code for every device. You introduced platform device driver entry for pl011 and only sbsa use platform device probe method currently. I am trying to reuse this probe function, so need to add clock enabling code in this function.

If you did not find any issue in sbsa device tree case, I guess the clock is always enabled. For mobile platform, clock is auto gated for power saving in most of cases.

Quoted 6 lines

Quoted 4 lines

For ACPI case, it may be handled automatically. If you agree my opinion, I will move these lines to patch 1. Please correct me if I am wrong.

Quoted 7 lines

Quoted 2 lines

I think you need to create a separate patch that adds that call, and make sure it's tested by other platforms before it gets accepted.

These code only impact sbsa device as only sbsa device is initialized via platform driver entry. So only your flavor is need for testing the code. Thanks! :-)

In SBSA mode the UART clock is always enabled by the firmware and there are no baud rate registers so we don't need to know the value of the clock. In ACPI there is no method to represent the clock. So if you add lines to unconditionally require a clock you will break SBSA mode in ACPI.

Quoted 1 line

Graeme

Right, Timur also already point out breakage of ACPI case. So I plan to move clocking enabling code to device tree case handling. Do you still have any other concern?

drivers/tty/serial/amba-pl011.c static int sbsa_uart_probe(struct platform_device *pdev) · line 2581

Quoted 2 lines · Jun Nie

drivers/tty/serial/amba-pl011.c +1 -1

-       snprintf(uap->type, sizeof(uap->type), "SBSA");
+       snprintf(uap->type, sizeof(uap->type), "PL011 plat");

I'm not crazy about this. I think you need to add a "const char *name" field to 'struct vendor_data'.

--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation collaborative project.

Will address this suggestion in next version patch. How about "PL011 SBSA" "PL011 ZTE" "PL011 ARM rev1" "PL011 ST rev1"?

make sbsa uart platform driver more generic so that platform driver code can be reused by ZTE uart platform driver.