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[Xen-devel] [PATCH V8] ns16550: Add support for UART present in Broadcom TruManage capable NetXtreme chips



Since it is an MMIO device, the code has been modified to accept MMIO based
devices as well. MMIO device settings are populated in the 'uart_config' table.
It also advertises 64 bit BAR. Therefore, code is reworked to account for 64
bit BAR and 64 bit MMIO lengths.

Some more quirks are - the need to shift the register offset by a specific
value and we also need to verify (UART_LSR_THRE && UART_LSR_TEMT) bits before
transmitting data.

While testing, include com1=115200,8n1,pci,0 on the xen cmdline to observe
output on console using SoL.

Changes from V7:
  - per Jan's comments:
    - Moving pci_ro_device to ns16550_init_postirq() so that either
      one of pci_hide_device or pci_ro_device is done at one place
    - remove leading '0' from printk as absent segment identifier
      implies zero anyway.
  - per Ian's comments:
    - fixed issues that casued his build to fail.
    - cross-compiled for arm32 and arm64 after applying patch and
      build was successful on local machine.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
Signed-off-by: Thomas Lendacky <Thomas.Lendacky@xxxxxxx>
---
 xen/drivers/char/ns16550.c | 187 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 166 insertions(+), 21 deletions(-)

diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c
index 9c2cded..932d643 100644
--- a/xen/drivers/char/ns16550.c
+++ b/xen/drivers/char/ns16550.c
@@ -46,13 +46,14 @@ string_param("com2", opt_com2);
 static struct ns16550 {
     int baud, clock_hz, data_bits, parity, stop_bits, fifo_size, irq;
     u64 io_base;   /* I/O port or memory-mapped I/O address. */
-    u32 io_size;
+    u64 io_size;
     int reg_shift; /* Bits to shift register offset by */
     int reg_width; /* Size of access to use, the registers
                     * themselves are still bytes */
     char __iomem *remapped_io_base;  /* Remapped virtual address of MMIO. */
     /* UART with IRQ line: interrupt-driven I/O. */
     struct irqaction irqaction;
+    u8 lsr_mask;
 #ifdef CONFIG_ARM
     struct vuart_info vuart;
 #endif
@@ -69,14 +70,50 @@ static struct ns16550 {
     bool_t pb_bdf_enable;   /* if =1, pb-bdf effective, port behind bridge */
     bool_t ps_bdf_enable;   /* if =1, ps_bdf effective, port on pci card */
     u32 bar;
+    u32 bar64;
     u16 cr;
     u8 bar_idx;
+    bool_t enable_ro; /* Make MMIO devices read only to Dom0 */
 #endif
 #ifdef HAS_DEVICE_TREE
     struct dt_irq dt_irq;
 #endif
 } ns16550_com[2] = { { 0 } };
 
+/* Defining uart config options for MMIO devices */
+struct ns16550_config_mmio {
+    u16 vendor_id;
+    u16 dev_id;
+    unsigned int reg_shift;
+    unsigned int reg_width;
+    unsigned int fifo_size;
+    u8 lsr_mask;
+    unsigned int max_bars;
+};
+
+
+#ifdef HAS_PCI
+/*
+ * Create lookup tables for specific MMIO devices..
+ * It is assumed that if the device found is MMIO,
+ * then you have indexed it here. Else, the driver
+ * does nothing.
+ */
+static struct ns16550_config_mmio __initdata uart_config[] =
+{
+    /* Broadcom TruManage device */
+    {
+        .vendor_id = 0x14e4,
+        .dev_id = 0x160a,
+        .reg_shift = 2,
+        .reg_width = 1,
+        .fifo_size = 16,
+        .lsr_mask = (UART_LSR_THRE | UART_LSR_TEMT),
+        .max_bars = 1,
+    },
+};
+#endif
+
 static void ns16550_delayed_resume(void *data);
 
 static char ns_read_reg(struct ns16550 *uart, int reg)
@@ -134,7 +171,7 @@ static void ns16550_interrupt(
     while ( !(ns_read_reg(uart, UART_IIR) & UART_IIR_NOINT) )
     {
         char lsr = ns_read_reg(uart, UART_LSR);
-        if ( lsr & UART_LSR_THRE )
+        if ( (lsr & uart->lsr_mask) == uart->lsr_mask )
             serial_tx_interrupt(port, regs);
         if ( lsr & UART_LSR_DR )
             serial_rx_interrupt(port, regs);
@@ -160,7 +197,7 @@ static void __ns16550_poll(struct cpu_user_regs *regs)
         serial_rx_interrupt(port, regs);
     }
 
-    if ( ns_read_reg(uart, UART_LSR) & UART_LSR_THRE )
+    if ( ( ns_read_reg(uart, UART_LSR) & uart->lsr_mask ) == uart->lsr_mask )
         serial_tx_interrupt(port, regs);
 
 out:
@@ -183,7 +220,9 @@ static int ns16550_tx_ready(struct serial_port *port)
 
     if ( ns16550_ioport_invalid(uart) )
         return -EIO;
-    return ns_read_reg(uart, UART_LSR) & UART_LSR_THRE ? uart->fifo_size : 0;
+
+    return ( (ns_read_reg(uart, UART_LSR) &
+              uart->lsr_mask ) == uart->lsr_mask ) ? uart->fifo_size : 0;
 }
 
 static void ns16550_putc(struct serial_port *port, char c)
@@ -354,8 +393,24 @@ static void __init ns16550_init_postirq(struct serial_port 
*port)
 
 #ifdef HAS_PCI
     if ( uart->bar || uart->ps_bdf_enable )
-        pci_hide_device(uart->ps_bdf[0], PCI_DEVFN(uart->ps_bdf[1],
-                                                   uart->ps_bdf[2]));
+    {
+        if ( !uart->enable_ro )
+            pci_hide_device(uart->ps_bdf[0], PCI_DEVFN(uart->ps_bdf[1],
+                            uart->ps_bdf[2]));
+        else
+        {
+            if ( rangeset_add_range(mmio_ro_ranges,
+                                    uart->io_base,
+                                    uart->io_base + uart->io_size - 1) )
+                printk(XENLOG_INFO "Error while adding MMIO range of device to 
mmio_ro_ranges\n");
+
+            if ( pci_ro_device(0, uart->ps_bdf[0],
+                               PCI_DEVFN(uart->ps_bdf[1], uart->ps_bdf[2])) )
+                printk(XENLOG_INFO "Could not mark config space of 
%02x:%02x.%u read-only.\n",
+                                    uart->ps_bdf[0], uart->ps_bdf[1],
+                                    uart->ps_bdf[2]);
+        }
+    }
 #endif
 }
 
@@ -381,6 +436,13 @@ static void _ns16550_resume(struct serial_port *port)
     {
        pci_conf_write32(0, uart->ps_bdf[0], uart->ps_bdf[1], uart->ps_bdf[2],
                         PCI_BASE_ADDRESS_0 + uart->bar_idx*4, uart->bar);
+
+        /* If 64 bit BAR, write higher 32 bits to BAR+4 */
+        if ( uart->bar & PCI_BASE_ADDRESS_MEM_TYPE_64 )
+            pci_conf_write32(0, uart->ps_bdf[0],
+                        uart->ps_bdf[1], uart->ps_bdf[2],
+                        PCI_BASE_ADDRESS_0 + (uart->bar_idx+1)*4, uart->bar64);
+
        pci_conf_write16(0, uart->ps_bdf[0], uart->ps_bdf[1], uart->ps_bdf[2],
                         PCI_COMMAND, uart->cr);
     }
@@ -546,11 +608,13 @@ static int __init check_existence(struct ns16550 *uart)
 }
 
 #ifdef HAS_PCI
-static int
+static int __init
 pci_uart_config (struct ns16550 *uart, int skip_amt, int bar_idx)
 {
-    uint32_t bar, len;
-    int b, d, f, nextf;
+    uint32_t bar, bar_64 = 0, len, len_64;
+    u64 size, mask;
+    unsigned int b, d, f, nextf, i;
+    u16 vendor, device;
 
     /* NB. Start at bus 1 to avoid AMT: a plug-in card cannot be on bus 0. */
     for ( b = skip_amt ? 1 : 0; b < 0x100; b++ )
@@ -579,24 +643,98 @@ pci_uart_config (struct ns16550 *uart, int skip_amt, int 
bar_idx)
                 bar = pci_conf_read32(0, b, d, f,
                                       PCI_BASE_ADDRESS_0 + bar_idx*4);
 
-                /* Not IO */
+                /* MMIO based */
                 if ( !(bar & PCI_BASE_ADDRESS_SPACE_IO) )
-                    continue;
-
-                pci_conf_write32(0, b, d, f, PCI_BASE_ADDRESS_0, ~0u);
-                len = pci_conf_read32(0, b, d, f, PCI_BASE_ADDRESS_0);
-                pci_conf_write32(0, b, d, f, PCI_BASE_ADDRESS_0 + bar_idx*4, 
bar);
-
-                /* Not 8 bytes */
-                if ( (len & 0xffff) != 0xfff9 )
-                    continue;
+                {
+                    vendor = pci_conf_read16(0, b, d, f, PCI_VENDOR_ID);
+                    device = pci_conf_read16(0, b, d, f, PCI_DEVICE_ID);
+
+                    pci_conf_write32(0, b, d, f,
+                                     PCI_BASE_ADDRESS_0 + bar_idx*4, ~0u);
+                    len = pci_conf_read32(0, b, d, f, PCI_BASE_ADDRESS_0 + 
bar_idx*4);
+                    pci_conf_write32(0, b, d, f,
+                                     PCI_BASE_ADDRESS_0 + bar_idx*4, bar);
+
+                    /* Handle 64 bit BAR if found */
+                    if ( bar & PCI_BASE_ADDRESS_MEM_TYPE_64 )
+                    {
+                        bar_64 = pci_conf_read32(0, b, d, f,
+                                      PCI_BASE_ADDRESS_0 + (bar_idx+1)*4);
+                        pci_conf_write32(0, b, d, f,
+                                    PCI_BASE_ADDRESS_0 + (bar_idx+1)*4, ~0u);
+                        len_64 = pci_conf_read32(0, b, d, f,
+                                    PCI_BASE_ADDRESS_0 + (bar_idx+1)*4);
+                        pci_conf_write32(0, b, d, f,
+                                    PCI_BASE_ADDRESS_0 + (bar_idx+1)*4, 
bar_64);
+                        mask = ((u64)~0 << 32) | PCI_BASE_ADDRESS_MEM_MASK;
+                        size = (((u64)len_64 << 32) | len) & mask;
+                    }
+                    else
+                        size = len & PCI_BASE_ADDRESS_MEM_MASK;
+
+                    size &= -size;
+
+                    /* Check for quirks in uart_config lookup table */
+                    for ( i = 0; i < ARRAY_SIZE(uart_config); i++)
+                    {
+                        if ( uart_config[i].vendor_id != vendor )
+                            continue;
+
+                        if ( uart_config[i].dev_id != device )
+                            continue;
+
+                        /*
+                         * Force length of mmio region to be at least
+                         * 8 bytes times (1 << reg_shift)
+                         */
+                        if ( size < (0x8 * (1 << uart_config[i].reg_shift)) )
+                            continue;
+
+                        if ( bar_idx >= uart_config[i].max_bars )
+                            continue;
+
+                        if ( uart_config[i].fifo_size )
+                            uart->fifo_size = uart_config[i].fifo_size;
+
+                        uart->reg_shift = uart_config[i].reg_shift;
+                        uart->reg_width = uart_config[i].reg_width;
+                        uart->lsr_mask = uart_config[i].lsr_mask;
+                        uart->io_base = ((u64)bar_64 << 32) |
+                                        (bar & PCI_BASE_ADDRESS_MEM_MASK);
+                        /* Set device and MMIO region read only to Dom0 */
+                        uart->enable_ro = 1;
+                        break;
+                    }
+
+                    /* If we have an io_base, then we succeeded in the lookup 
*/
+                    if ( !uart->io_base )
+                        continue;
+                }
+                /* IO based */
+                else
+                {
+                    pci_conf_write32(0, b, d, f,
+                                     PCI_BASE_ADDRESS_0 + bar_idx*4, ~0u);
+                    len = pci_conf_read32(0, b, d, f, PCI_BASE_ADDRESS_0);
+                    pci_conf_write32(0, b, d, f,
+                                     PCI_BASE_ADDRESS_0 + bar_idx*4, bar);
+                    size = len & PCI_BASE_ADDRESS_IO_MASK;
+                    size &= -size;
+
+                    /* Not 8 bytes */
+                    if ( size != 0x8 )
+                        continue;
+
+                    uart->io_base = bar & ~PCI_BASE_ADDRESS_SPACE_IO;
+                }
 
                 uart->ps_bdf[0] = b;
                 uart->ps_bdf[1] = d;
                 uart->ps_bdf[2] = f;
-                uart->bar = bar;
                 uart->bar_idx = bar_idx;
-                uart->io_base = bar & ~PCI_BASE_ADDRESS_SPACE_IO;
+                uart->bar = bar;
+                uart->bar64 = bar_64;
+                uart->io_size = size;
                 uart->irq = pci_conf_read8(0, b, d, f, PCI_INTERRUPT_PIN) ?
                     pci_conf_read8(0, b, d, f, PCI_INTERRUPT_LINE) : 0;
 
@@ -743,9 +881,16 @@ void __init ns16550_init(int index, struct 
ns16550_defaults *defaults)
     uart->reg_width = 1;
     uart->reg_shift = 0;
 
+#ifdef HAS_PCI
+    uart->enable_ro = 0;
+#endif
+
     /* Default is no transmit FIFO. */
     uart->fifo_size = 1;
 
+    /* Default lsr_mask = UART_LSR_THRE */
+    uart->lsr_mask = UART_LSR_THRE;
+
     ns16550_parse_port_config(uart, (index == 0) ? opt_com1 : opt_com2);
 }
 
-- 
1.8.1.2



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